FH Universities of Applied Sciences HES Fachhochschulen – … · 2019. 8. 30. · Universities of Applied Sciences Fachhochschulen – Hautes Ecoles Spécialisées FH HES Materials

Columns CHIMIA 2019 73 No 78 645doi102533chimia2019645 Chimia 73 (2019) 645ndash655 copy Swiss Chemical Society

Universities of Applied Sciences

Fachhochschulen ndash Hautes Ecoles SpeacutecialiseacuteesFHHES

Materials Science at Swiss Universities of AppliedSciences

Pierre Brodarda Michal Dabrosa Roger MartiaEnnio Vanolia Manfred Zinnb Urban Freyb ChristianAdlhartc Lucy Kindd Franziska Kochd Floriana BurgiodJohan Stenqvistd Sina Saxerd Uwe Pielesd PatrickShahgaldiand and Sebastian Wendebornd

Correspondence Prof P Brodarda E-mail pierrebrodardhefrchaHEIA-FR Haute eacutecole speacutecialiseacutee de Suisse occidentale Haute eacutecole drsquoingeacutenierieet drsquoarchitecture Fribourg Institute of Chemical Technology Boulevard de Peacuterolles80 CH-1700 Fribourg bHES-SO Haute eacutecole speacutecialiseacutee de Suisse occidentaleHES-SOValais-Wallis Institute of Life Technologies Route du Rawyl 64CH-1950 Sion 2 cZHAW Zuumlrcher Hochschule fuumlr Angewandte WissenschaftenLife Sciences und Facility Management Institut fuumlr Chemie und BiotechnologieEinsiedlerstrasse 31 CH-8820 Waumldenswil dFHNW Fachhochschule Nordwest-schweiz Hochschule fuumlr Life Sciences Institut fuumlr Chemie und Bioanalytik Hof-ackerstrasse 30 CH-4132 Muttenz

Abstract In the Swiss Universities of Applied Sciences severalresearch institutes are involved in Materials Science withdifferent approaches and applications fields A few examplesof recent projects from different groups of the Universityof Applied Sciences and Arts Western Switzerland (HES-SO) the Zurich University of Applied Sciences (ZHAW) andthe University of Applied Sciences and Arts NorthwesternSwitzerland (FHNW) are given

Keywords Biocatalysis middot Biomaterials middot Biomineralization middotHeterogeneous catalysis middot Materials Science middot Photografting middotPolymers middot Porous Materials middot Processing middot Self-Assembly middotSynthetic fuels middot Tissue engineering middot Zirconia coatings

1 IntroductionMaterials science plays a major economic and social role

For instance because of acute environmental concerns more ef-ficient use of material and energy resources is urgently requiredMaterials science is helping to develop new energy technolo-gies more energy efficient devices and easily recyclable andless toxic materials Overcoming disease is another topic wherematerials science in conjunction with biotechnology can play arole eg by developing artificial bones and organ implants orfor safe drug delivery systems Materials science can improvenot only the performance of the products but also the ways theyare produced and handled considering their full life cycle (egpackaging)

The ability to control manipulate and designmaterials on thenanometer scale (10ndash9m)will be one of themajor technology driv-ers of the 21st Century The potential of these materials for gen-erating new functionalities minimizing waste and pollution andoptimizing properties and performance is huge Nanomaterialsare being developed from almost every type of material includ-ing polymers metals ceramics composites and biomaterials Ina number of cases it is now possible to predict materials proper-ties before they have even beenmanufactured thus greatly reduc-ing the time spent on testing and development The objective ofmodern materials science is to tailor a material in order to obtaina desired set of properties suitable for a given application Onearea of research that will revolutionize our concept of syntheticmaterials as well as how we interact with our surroundings are

lsquosmartrsquo materials Unlike normal inert materials smart materi-als are designed to respond to external stimuli adapting to theirenvironment in order to boost performance extend their usefullifetimes save energy or simply adjust conditions to be morecomfortable for human beings The rapidly emerging field ofbiomimetic materials forms another very important technologytoday Biomimetic materials seek to replicate or mimic biologicalprocesses and materials both inorganic and organic To developthese materials we need new chemical strategies that combineself-assembly with the ability to form hierarchically structuredmaterials Finally materials scientists constantly require new andmore powerful analytical techniques so that they can continuethe discovery of new phenomena and develop improved materi-als for the future

This article is intended to highlight the current research onMaterials Science in the Swiss Universities of Applied Sciencesand more specifically projects that strongly involve chemistry inthe general sense

2 HEIA-FR ndash Haute Ecole drsquoIngeacutenierie etdrsquoArchitecture de Fribourg

Several examples of research activities dealing with mate-rials at the Institute of Chemical Technology of the HEIA-FRare presented namely on polymers and plasma-sprayed zirconiacoatings

21 PolymersThe institute ChemTech has various activities in develop-

ment synthesis and scale-up of novel and innovative polymericmaterials (Profs Dr Roger Marti amp Ennio Vanoli) A recentsuccessful example is the development of novel dental poly-mers Current dental polymers suffer from limited stability byenzymatic attack in the saliva Beside the mechanical degra-dation of the filling it liberates small molecules which causeallergic reactions In a project financed by Innosuisse togetherwith the industrial partner SaremcoAG and HES-SOValais theinstitute ChemTech worked on the optimization of the polymerstructure Novel more stable pre-polymers based on classi-cal dental monomers were prepared and formulated into noveldental composites The best new dental composites producedaround 10 times less degradation products than current materi-als A safe and reproducible scale-up of the synthesis of thepre-polymer on a multi-kg scale was performed which allowsmarketing the new dental material with improved biocompat-ibility under the name lsquoSAREMCO APT ndash Advanced PolymerTechnologyrsquo (Fig 1 left)

Another activity is hydrogels ndash these are three-dimension-al network structures which can absorb and retain significantamounts of water They can be obtained from synthetic andornatural polymers and we developed in collaboration with theresearch group of Prof Stoppini at HES-SO Geneva (HEPIA)a toolbox to support applications in tissue engineering and bio-printing A variety of building blocks for the synthesis of hydro-gels were prepared (thiol allyl and hydrazone modified hyal-uronic acid and gelatin with various degree of functionalizationallyl PEG derivatives for thiol-ene cross-linking) that allow thesynthesis of hydrogels by UV or thermal cross-linking Thesenew hydrogels were successfully used in bio-printing (in col-

646 CHIMIA 2019 73 No 78 Columns

laboration with institute iPRINT of HEIA-FR) drug delivery andtissue engineering application (Fig 1 right)

The ChemTech Institute in collaboration with the PlasticInnovation Competence Center PICC in Fribourg participatesin the European project BIOSMART for the development ofnovel bio-based packaging applications (biosmart-projecteu)In our labs we are working on polyester amide block poly-mers which are fully bio-sourced and biodegradable By vary-ing the chemical structure ndash the hard and soft segment ndash wecan fine-tune and adjust the physico-chemical mechanical andbarrier properties Scale-up studies with kneader reactors byLIST Technology AG are under way to prepare larger quan-tities and evaluate the industrialization of these biopolymersBeside these polyester amides the institute ChemTech workson polylactic acid (PLA) especially in the synthesis of the lac-tide monomer and its reactive extrusion via ring opening po-lymerization (ROP) as a sustainable process

The ChemTech Institute is also active in material recyclingprojects some of which are carried out in collaboration with de-veloping countries In a recent project involving partners in sub-SaharanAfrica the group developed and optimized an innovativemethod of recycling used vehicle tires into versatile rubber tilesThe technique consists of grinding the tires into rubber particlesseparating out the tissue and metal components and condition-ing the particles to form tiles that can be used for flooring orinsulation purposes The novelty of the approach is that no glueor binder is needed in the process making the technique cheapersafer and more widely accessible

One of the biggest challenge of plastics industries is to predicthow the material will age Indeed extremely various applica-tions expose the base polymers to strong temperatures variationssunlight air aggressive chemicals etc all contributing to theirdegradation Base material suppliers provide indications of age-ing based on standardized tests but application industries areproducing final objects exposed to non-constant environmentalstresses often for much longer times than advised by the basematerial suppliers In order to help these companies producingfinal polymer-based products several publicndashprivate researchprojects have been carried out at HEIA-FRChemTech In col-laboration with major industrial partners of the Fribourg regionproducing polymer goods ranging from water tubes to automo-tive components and electric connectors the research team ledby Prof Dr Pierre Brodard selected the most appropriate char-acterization methods[1]

In 2014ndash2015 the POLYAGE project focused on chemicalageing of polyethylene- and polyamide-based plastics (PE andPA)[23] New samples were first fully characterized by differen-tial scanning calorimetry thermogravimetric analysis infraredand Raman spectroscopy and scanning electron microscopyThen the samples were exposed to various temperature programsto force their degradation and compared to aged products pro-vided by our industrial partners As expected PE-based materi-als are chemically decomposed by oxidation which was easilyconfirmed by spectroscopy and we were able to quantify thekinetics of oxidation by chemiluminescence thus allowing an

exact prediction of the lifetime of the samples at any temperatureOn the other hand PA-based materials did not seem to changetheir chemical composition even though their mechanical integ-rity was strongly fading during ageing their infrared and Ramanspectra were almost unaffected Indeed the fracture toughnessmeasured by tensile tests was reduced by 40 in the hardestconditions (20 days at 200 degC) but the composition remainedthe same We then found out that the structure of the materialhad changed SEM images revealed a highly inhomogeneousdispersal of the glass fibers in the reinforced PA-based samplesafter thermal ageing which probably accounts for their apparentfragility (Fig 2)

As a logical next step we decided to concentrate on physi-cal ageing in the follow-up project POLYLIFE in 2015ndash2016[4] By physical ageing we mean no change in the chemicalcomposition but a modification of the structure like the above-mentioned alteration of the glass fibers distribution in the PAmatrix For this purpose and with the strong support of ourmechanical engineering department a new method based onultrasound was developed a piezoelectric transducer generatesultrasonic waves in the sample and an interferometric laserhead is used for detection Two implementations have beendevised ultrasonic Lamb waves propagating in the plane ofa thin flat sample and mapped by the scanning laser head al-lowing determination of the elastic modulus of the material indifferent directions and resonance of ultrasonic frequenciesthrough the sample enabling to measure more complicatednon-flat objects (Fig 3)

These two non-destructive techniques are sensitive to anymodification of the physical structure even on final industrialproducts Both approaches are in excellent correlation with me-chanical properties obtained by macroscopic (tensile test) andmicroscopic (nanoindentation) methods For the PA-based sam-ples exposed to several temperature programs (160 degC to 270 degC30 h to 3000 h) we found out a temperature-dependent exponen-tial decay of the fracture toughness with time Based on theseresults we were able to calculate the kinetics parameters andpredict their lifetimes

Recently we investigated the recycling process of a high-performance engineering polymer Small parts produced withthis material generate a significant quantity of offcuts (~60)that must be reprocessed (Fig 4) to be re-useable for furtherproduction an operation inducing a large thermal load on thepolymer[5]

We found out that the chemical stability is proved up to 3 cy-cles of re-extrusion under inert atmosphere but that theYoungrsquosmodulus slightly decreases due to a decrease in the length of thereinforcing glass fibers observed during the recycling process bymicro CT-scan However the decisive element to assert whetherthe recycled material is suitable or not is to test it on parts inproduction at the industrial level a process now in progress inthe companies

Fig 1 The novel dental material lsquoSAREMCO APT ndash Advanced PolymerTechnologyrsquo with improved biocompatibility (left) and hydrogel materials(right)

Fig 2 SEM images of PA before (a) and after (b) thermal ageing at200 degC for 20 days

Columns CHIMIA 2019 73 No 78 647

22 Zirconia CoatingsAnother example is plasma spraying In this process ma-

terial in the form of powder is injected into a very high tem-perature plasma flame where it is rapidly heated and acceler-ated to a high velocity The individual molten particles impacton a substrate kept in front of the plasma gun and stick to thesubstrate These deformed particles are known as splats withlayers of splats building up a coating[6] The first layer of splatsdetermines the adhesion of the coating to the substrate duringfreezing the coefficients of thermal expansion of the splat andthe substrate materials being different the splat experiences re-sidual stress A stressed splat depending on the magnitude ofthe stress can either crack significantly or peel off completelyfrom the substrate and thus initiate coating failure at either thesplatndashsplat or splatndashsubstrate interfaces Hence residual stressis a very important factor in determining coating cohesion andadhesion As-sprayed coatings are porous but it is possible toreduce the porosity to a great extent and improve the coatingproperties by remelting the coating using a laser For examplezirconia thermal barrier coatings can be laser-remelted to sealthe coating and prevent ingress of corrosive gases to the me-tallic bond coat However laser remelting modifies the natureof residual stress of the coating Raman spectroscopy can beeffectively used for strain determination for materials like zir-conia which has a Raman active tetragonal phase and the rela-tion between the applied stress in zirconia coating and Ramanshift is linear Micro-Raman spectroscopy focuses an excitinglaser beam with a microscope objective down to a few microm andhence is suitable for detecting residual stress in splats (typicaldiameters 40ndash100 microm) The strain is measured from the differ-ence in Raman peak position of a stressed sample relative to astress-free sample (as-received powders)

Splats and coating deposition were carried out by ProfessorPartha P Bandyopadhyay at the Indian Institute of Technology ofKharagpur West Bengal India Prior to deposition steel sampleswere grit blasted and a layer of NiCrAlY bond coat was depos-ited on this roughened surface The bond coat layer was polishedand zirconia splats were then deposited on the polished substratesRaman spectroscopy was undertaken at HEIA-FR First as-re-ceived powders assumed to be stress-free were measured and thetetragonal peak found at 63835 cmndash1 was selected as a referencea peak shift above this wavenumber is attributed to a compressiveresidual stress and a peak shift belowmeans tensile residual stress(a shift of 1 cmndash1 corresponds to a residual stress of 220 MPa)

Fig 5 shows the variation of splat residual stress with par-ticle velocity and temperature calculated by averaging the dataobtained from 1000 particles The melting point of zirconia isaround 2715 degC and hence this temperature was chosen forspraying In all cases the stress was tensile this is attributed torapid quenching of the splats when it hits the substrate Duringquenching the splat shrinks and this shrinkage is retarded bythe substrate hence a tensile stress develops in the splat It alsoappears that splat residual stress does not have any direct correla-tion with either particle speed or temperature The average stressin remelted splats is much less than that of as-sprayed splats Alaser-remelted splat forms a large molten pool that cools slowlyas compared to an as-sprayed splat Hence the residual stresskeeps low Laser remelting also produces an annealing effect onthe metal surrounding the splat

Fig 6 shows the residual stress profiles of the as-sprayedand laser-remelted samples The as-sprayed coating sampleshows a moderate tensile stress through the entire cross-sectionHowever in the laser remelted coating a transition to compres-sive stress occurs in the remelted layer In both cases the stressesweremoderate as compared to single splatsA highly tensile splatis compressed by the splat deposited above it In addition in ce-ramic coatings stress relief occurs due to cracking As a resultthe stress in coatings kept lower Raman spectroscopy appears

Fig 4 Twin screw extruder for offcuts reprocessing

Fig 3 Ultrasonic characterization method with a) waves propagating in the plane or b) through the sample

Fig 5 Variation of splat residual stress with a) particle velocity and b)temperature


to be a potent tool for experimental stress analysis of thermallysprayed coatings and we proved that it is possible to analyzesmall features like splats as well as to perform stress depth profil-ing of bulk coatings[7]

3 HES-SO Valais-Wallis ndash Haute eacutecole speacutecialiseacuteede Suisse occidentale Sion

31 Polymeric BiomaterialsThebiosynthesischemicalmodificationpurificationandappli-

cation of biopolymers for industrial andmedical purposes is one ofthe main foci of the research group Biotechnology and SustainableChemistry (BioSusChem) at the Institute of Life Technologies ofHES-SO Valais-Wallis Besides the biopolyesters polyhydroxyal-kanoate (PHA) polylactate (PLA) and poly(lactate-co-glycolate)(PLGA) also proteins (eg collagen) and polysaccharides (egpullulan and microbial cellulose) are investigated with respect totheir medical or industrial applications (Fig 7)

A particular expertise of BioSusChem is the biosynthesisof PHA in bacteria using fed-batch and continuous cultivationTypically the cells deposit PHA intracellularly as a carbon andenergy storage compound when a nutrient (nitrogen phosphorussulfur etc) is limiting growth and the carbon source is availablein ample amounts In order to fine-tune the biosynthesis of PHAmuch effort has been put on the design of the culture medium toestablish multiple nutrient-limited (MNL) growth conditions[8]Under such a growth regime wild-type and recombinant mi-croorganisms accumulate large amounts of polymers and mostimportantly the flux of carbon substrates into the cell can becontrolled resulting in a tailored monomeric unit compositionthat finally determines also the chemo-physical properties of thePHA produced This had been exemplified by the tailored bio-synthesis of the PHA poly(3-hydroxybutyrate-co-3-hydroxyval-erate) (PHBV) inCupriavidus necator enabling the control of themelting temperature between 80ndash180 degC[9] A similar approachwas used for tailoring the functionality of the side chains inPseudomonas putida GPo1 by the feed of functional fatty acidsduring chemostat cultivation Double bonds in the ω-position ofthe side chains are of particular interest because they are veryreactive to chemical modifications using mild chemistry Thusthe first organicndashinorganic PHA hybrid copolymer could be pro-duced with the free radical addition of the nano-cage polyhedraloligomeric silsesquioxane containing seven isobutyl groups andone mercaptopropyl group (POSS-SH) to the olefinic PHA side-chain The melting temperature (Tm) increased from 48ndash120 degCdue to this modification[10] Other reactions such as epoxidationor the synthesis of comb-polymers showed a significant influenceon the material properties too

Genetic engineering of metabolic pathways using traditionalor modern CRISPR-CAS9 techniques[11] or the engineeringof key enzymes (eg PHA polymerase) are elaborated tools to

extend the material properties of PHAs In general PHAs havean excellent biocompatibility making them also interesting can-didates for medical applications Recently the biosynthesis ofpoly(4-hydroxybutyrate) (P4HB) could be optimized to enable acheaper production with a recombinant Escherichia coli strain[12] To date P4HB is routinely produced at HES-SO Valais forresearch purposes or during contract fermentations for compa-nies that are interested in testing this FDA-approved polymer forspecific medical applications

In an ongoing collaboration with Prof K Matsumoto at theUniversity of Hokkaido (Japan) the growth of an engineeredE coli strain was assessed that contained a lactate polymer-izing enzyme (LPE) to enable the polymerization of unusualmonomeric units such as lactic acid into PHA[13] This strain isable to biosynthesize the copolymer poly(3-hydroxybutyrate-co-2-hydroxypropionate) (P(HB-co-LA)) even at higher celldensities[14]

The synthesis of block-copolymeric PHAs either producedin vivo by bacteria or by (bio-) chemical modification after bio-synthesis in vitro is currently being investigated in a project sup-ported by the Swiss Higher Education Council The first resultsdemonstrated that blocky PHAs have extended material proper-ties because of the combination of the chemophysical propertiesof their blocks The goal of this research is to design a PHA-basedbioplastic that does not need any addition of typical additivessuch as softeners UV stabilizers or crystallization agents

Another important topic of the BioSusChem group is the de-sign of sustainable PHA production to avoid the conflict lsquofoodto materialrsquo In a first approach it could be shown that the pom-aces of fruit wastes (cherry apple and apricots) could be usedas carbon sources for the biosynthesis of PHAs[15] In the wineregion Valais larger amounts of grape pomace end up as wasteduring wine production A simple washing procedure yielded ina glucose content of more than 150 g Lndash1 that was successfullyused for the production of olefinic PHAs[16]

Alternative interesting waste streams are gases Syngas a typ-ical waste gas in the steel industry that can also be produced fromorganic waste materials by pyrolysis was used for the biosyn-thesis of poly(3-hydroxybutyrate) (PHB) in Rhodospirillum ru-brum[17] Different anaerobic multiple nutrient-limited fed-batchcultivations were assessed that were based on CO as energy andacetate as PHB source Interestingly a limitation by phosphatein the culture medium yielded in doubled amounts of PHB in thebiomass (30 ww) in comparison to the traditionally used ni-trogen limitation[18]Along with PHB also H

2was produced that

could be eventually applied for energy gain by fuel cellsIn an ongoing HES-SO project this gained knowhow in

gas fermentations is applied to the aerobic fermentation ofCupriavidus necator in presence of CO

2 H

2 This CO

2negative

fermentation process worked very well at the lab scale and willbe scaled-up to a 300 L bioreactor at Martigny (VS) within 2019

32 Particular Processing of BiomaterialsIn a joint project with Prof E Carrentildeo (HES-SO Valais)

PHA was tested whether it could be used in metal powder injec-tion molding (MIM) as a binder molecule[19] Best performancewas found for PHBV with nickel-free stainless steel powderwhen it was blended with paraffin wax and stearic acid[20] Thismetalndashorganic blend was further processed by injection moldingat 120 degC to form green parts that were subsequently debindedfirstly in organic solvent and secondly by heat and finally sin-tered at 1260 degC with the complete removal of PHBV The re-sulting stainless steel part had suitable properties and displayeda surface structure appropriate for medical applications eg asbone implant

A flexible electrode for transcutaneous electrical nerve stimu-lation (TENS) and electrocardiography applications was devel-

Fig 6 Residual stress profile of as-sprayed and remelted samples


oped in collaboration with Prof S Schintke at HEIG PHAswere blended with silver nanowires (AgNW) to obtain differ-ent conductivities A prototype with a film thickness of 150 micromwith PHB and a AgNW content of 3 wt with an average con-ductivity of 253 S mndash1 was manufactured and found to be suit-able for TENS[21] (see also video httpswwwhes-sochdebio-flex-4668html)

The Innosuisse project lsquoPolymeric NanoBioMaterials fordrug delivery developing and implementation of safe-by-designconcept enabling safe healthcare solutionsrsquo investigates the tox-icity and implementation of polymeric nanobiomaterials suchas chitosan PLA and PHA within an international consortiumWithin this project an electrospinning and electrosputtering unitwas constructed that also allows the integration of drugs in thePHA or other biopolymeric matrices Currently guidelines howto use and process the materials are in preparation (httpgo-nanobiomateu)

In 2020 HES-SO Valais will organize the 17th InternationalSymposium on Biopolymers (wwwisbp2020com) in Crans-Montana with about 200 participants where also one day will bededicated to industrial processing and applications It is antici-pated that this conference should also represent the Swiss activi-ties in the field of polymeric biomaterials

4 ZHAW ndash Zuumlrcher Hochschule fuumlr AngewandteWissenschaften Waumldenswil

The research of materials science at ZHAW is cultivated inthe Institute of Materials and Process Engineering as well as inthe Institute of Chemistry and Biotechnology Topics range frombiomaterials for drug testing coatings that will speed up Swissskiers catalysts to fundamentals in nano scale self-assembly anddifferent types of porous materials that are used as specific nanocontainers or for environmental remediation

41 BiomaterialsToday preclinical drug discovery still relies on tissue cultures

from sacrificed animals since 2D cell cultures do not reflect thein vivo situation Therefore we have developed a concept of a3D drug screening platform for the automated production of 3Dmusculoskeletal-tendon-like tissues that may be used to developtherapies against degenerative muscle and tendon diseases[22]The platform is compatible with multiwell plates and comprisedof a postholder where cells are bioprinted to be differentiated intothe corresponding tissues afterwards Bioprinting was achievedusing a gelatine methacryloyl-polyethylenglycol dimethacrylate(GelMA-PEGDMA)-based bioink that was photo-polymeriz-able at 365 nm We demonstrated the printing capabilities (Fig8) for mono- and co-cultures of primary rat tail tenocytes (printed

around the posts) and primary human skeletal muscle-derivedmyoblasts (printed in the interstice) After differentiation for 7days formation of tendon-andmuscle-like tissue was demonstrat-ed which showed auto contractions as well as electrical pulsestimulated contractions of single myofibers

42 PhotograftingDurability and hydrophobicity are the key elements of an ef-

ficient ski wax coating To render polyethylene surfaces stronglyand permanently hydrophobic photocatalytically generated ni-trenes were used as reactive groups to insert into the carbonndashhy-drogen bonds of polyethylene (Fig 9) The effect of photocata-lytically linked fluorocarbons was demonstrated by an up to 25fold increase in abrasion resistances as compared with polyethyl-ene surfaces conventionally coated with long-chain perfluoroal-kanes[23] Spectroscopic evidence for the grafted monolayer wasfound using UV and XPS[24] The efficiency of such equippedcross country skies was improved by 15

43 Catalysts for Synthetic fuelsTo enable the energy transition efficient and stable cata-

lysts for the conversion of CO2with regenerative H

2into energy

sources such as methane (CH4) have to be developed Catalysts

based on CoAl2O

3undergo deactivation by the formation of a

secondary CoAl2O

4phase This was avoided by substituting the

Al-based support with Mn The CoAl2xMn

xO

4supported catalyst

showed a drastically increased reducibility Starting from the spi-nel a significantly improved methanation catalyst was obtainedwhich was able to convert 80 CO

2at a selectivity of over 97

to methane at 350 degCIn addition the activation energy for the methanation de-

creases from 94 to 56 kJ molndash1 due to the modification of thespinel[25]

44 Self-AssemblyA promising way of developing reconfigurable materials is

self-assembly of micronanoparticles into suprastructures Shapeand amphiphilicity play a vital role in the self-assembly of colloi-dal particles Therefore as compared to spherical building blocksanisotropic colloidal particles may yield a significantly largervariety of self-assembled structures[26] The decisive functionalroles of self-assembled proteins in nature depend on the anisot-ropy of their building blocks Snowman-shaped Janus nanopar-ticles (JNPs) consisting of two different lobes were systemati-cally studied to understand the relationship between the shape ofthe colloidal building blocks and the assembled suprastructure(Fig 10) Geometrically different JNPs were synthesized frompoly(tert-butyl acrylate) nanoparticles (NPs) using seeded emul-sion polymerization Phase separation of 3-(triethoxysilyl)propylmethacrylate from the PtBA seed NPs allowed to the formationof JNPs These JNPs differed in the geometric aspects lobe sizeseparation degree and overall size[26] Depending on the geo-

Fig 7 Processing options for thermoplastic and functionalizedpolyhydroxyalkanoate (PHA)

Fig 8 Three-dimensional printed co-culture with tenocytes (green)around the posts and myoblasts (red) in the middle part of thedumbbell-shaped structure Adapted with permission from ref [22]


metrical parameters of the JNPs different self-assembled supra-structures were obtained from spherical micelles mono-walledcapsules planar mono-bilayers to capsules with randomly ori-ented JNPs (Fig 10) Such correlations between geometry andself-assembled structure have been well studied for surfactantsand an equivalent Janus critical packing parameter (JCpp) wassuggested to describe the self-assembly of JNPs depending ontheir shape[26]

In addition to geometry the amphiphilicity of JNPs can beswitched on or off which in turn affects their ability to self-as-semble at interfaces[27]At high (pH gt 70) pH values the amphi-philicity of JNPs containing amine groups on one lobe is switchedoff and their interfacial behavior was similar to that of homo-geneous nanoparticles but a low (pH lt 60) pH the interfacialactivity was enhanced and JNP stabilized Pickering emulsionsunderwent reversible water-in-oil to oil-in-water phase inversionwhen the aqueous phase changed from basic to acidic (Fig 10)Similarly foam formation of such JNP Pickering emulsions wasstrongly influenced by the pH[28]

45 Porous MaterialsPorous materials with defined pores in the microporous

(lt 2 nm) and mesoporous (2ndash50 nm) range are of particular inter-est for hostndashguest systems Guest molecules can be released fromthe nanoporous hosts in a controlled manner or stabilized againstdegradation Based on this concept a new type of colorant (TrueColor Pigments TCP) was developed[29] Conventional pigmentsare colorants that are insoluble in the application medium Theirhue however not only depends on the light absorption proper-

ties of the chromophores but also to a large extent on the particlesize and crystallinity Chemical properties are defined by the sur-face functional groups which have to be accounted for duringtheir application The extraordinarily stable ancient Maya Bluepigment relies on the hostndashguest concept of indigo incorporatedinto inorganic palygorskite but the variable presence of oxidizedindigo (dehydroindigo) gives rise to a peculiar hue Intercalationof indigo into zeolite L crystals followed by reductive washingand sealing of the indigo-filled nanochannels led to a colorant forwhich the colorimetric properties were only determined by theisolated guest molecules and were ndash in contrary to Maya Blue ndashidentical with the absorption spectrum of dissolved indigo mol-ecules The chemical properties on the other hand were definedby the zeolite L host As a consequence the formulation and ap-plication of such TCP is color-independent and the particle size isdetermined by the size of the zeolite crystals (04 microm in this case)

Post-condensed arrays of silica nanochannels (ASNCs) rep-resent functional mesoporous materials which are character-ized by a one-dimensional channel system with three inherentlydifferent surface regions pore entrances (hexagonal faces) ex-ternal surfaces (rectangular faces) and internal surfaces (cy-lindrical pores)[30] Pore entrances and internal surfaces wereselectively functionalized in a one-pot reaction using differentdriving forces such as steric hindrance and mobility supportedby an end-on particle growth (Fig 11) The materials providea platform for the development of drug delivery systems andsensors

Nanofiber aerogels (NFAs) or sponges are a recent class ofultralight highly porous materials containing a 3D fibrous net-work of pre-formed nanofibers[31] They lack the microporousproperties of classical aerogels but they allow a fine controlof the nature and architecture of the 3D fibrous network (Fig12) This is exploited in applications where controlled masstransport is combined with interfacial interactions such as forseparation or heat insulation[32] We prepared such nanofiberaerogels by electrospinning the biopolymer pullulan togetherwith PVA followed by cutting freeze drying and thermal cross-linking Such obtained materials are amphiphilic with large ab-sorption capacities of gt 100 m3 mndash3 for both water and non-polar solvents However upon silylation the fibrous surfacebecame water repellent allowing their application in environ-mental remediation as demonstrated for the purification of wa-ter from chlorinated hydrocarbons (Fig 12)[33] The OH groups

Fig 9 Fluorocarbon coated ski surface by photografting

Fig 10 (A) Self-assembled supracolloidal structures obtained from JNPs with different geometries (B) SEM image of snowman shaped JNPs (C)Representation of the Janus critical packing parameters 119869119869119869119869119869119869119869119869 = 119881119881119897119897 119886119886 (D) wo Pickering emulsion (toluenewater = 45 ratio pH gt 7) changing reversibly toow at pH lt 6 after addition of HCl Adapted with permission from ref [26] copyright copy 2018 American Chemical Society


of pullulan provide also favorable interactions with dissolvedimpurities such as organic dyes This was demonstrated in acontinuous process for the purification of water from the cat-ionic dye methylene blue The adsorption capacity was approx04 g dyeg NFA and twenty recycling cycles were achieved bysimply switching the pH[34]

Nanofiber-based materials are mostly applied in aerosol fil-tration since these thin fibers allow the separation of small parti-cles in the 100 nm range at decent differential pressure Howeverthere are given physical limits between high separation efficiencyand a low differential pressure asking for an increased filter areaTechnically this is solved by pleating the filters like an accor-dion NFAs however intrinsically contain such a pleated struc-ture where the major pores represent the interstice while the cellwalls are the effective filter Using NFAs we were able to achievegt 99998 filtration efficiency at considerably low differentialpressure of 550 Pa (Fig 12)[35]

5 School of Life Sciences University of AppliedSciences and Arts Northwestern Switzerland (FHNW)

The School of Life Sciences FHNW holds extended andmultidisciplinary expertise in many areas of modern materialsciences ranging from medicinal implant development to the3D printing of cells and bacteria for numerous applications Inthe following paragraphs we highlight some of those activities

The material science and nanotechnology research group ofProf Dr U Pieles at the University ofApplied Sciences andArtsNorthwestern Switzerland (FHNW) performs material scienceon nanoscale level with focus on surface chemistry technologyThe group works on a broad range of materials eg biomateri-als nanoparticles amp colloids ceramics polymers textiles pa-per construction material and so on The grouprsquos core-expertiseincludes state-of-the-art instruments amp techniques to performsynthetic manipulations and characterization of structures andmaterials The laboratory is equipped with chemical amp BSL2cabinets electron microscopes (TEM SEM) energy dispersiveX-ray (EDX) atomic force microscopy (AFM) X-ray photoelec-tron spectroscopy (XPS) quartz crystal microbalance (QCM-D)infrared- and Raman imaging microscopes and spectrometer la-ser confocal scanning microscope (LEXT) ellipsometer micro

computed tomography (microCT) and nanoindenter to determine vis-coelastic properties This comprehensive collection of techniquesallows the determination of important material parameters and adeep understanding of surface-related processes

The groups expertise and instrumentation is highly attractivefor small ampmedium enterprises who benefit in highly productivecollaborations with the School of Life Sciences FHNW Suchcollaborations address unmet challenges lead to new and innova-tive products or in-depth understanding of processes or productsThusmany of the activities of thematerials science and nanotech-nology group are performed in collaboration with industrial andor academic partners in direct-funded or governmental supportedprojects An extract of such projects is given below

51 Biomaterials for Dental TherapySelf-assembling peptide (SAP) hydrogels have been used for

several years in the area of tissue engineering and regenerativemedicine[36] Together with the Swiss company Credentis AGhydrogel forming P11-SAPs have been developed for the therapyof dental diseases such as the treatment of early caries lesionsWe have investigated the therapeutic effect of a P11-SAP for-mulation applied on affected tooth-lesions and its capability to

Fig 12 (A) Ultralight NFA sitting on a dandelion (B) Hierarchical cellular architecture of an NFA (C) Aerosol filtration efficiency of NFAs (D) Waterremediation using NFAs Adapted with permission from refs [313335]

Fig 11 SEM image of functionalized ASNCs Each of the particlescontains roughly 500rsquo000 parallel nanochannels (ca 4 nm in diameter)with the entrances located at the base surfaces of the hexagonalprisms The confocal laser scanning microscopy image shows anoptical slice through the center of a particle revealing fluorescence-labeled amino groups at the pore entrances (red) and thiol groups(green) at the internal surfaces The bifunctionalized region near thepore entrances appears yellow[30]


induce biomineralization and regeneration of the tooth[37] Theregeneration capacity of the P11-SAP formulation was evalu-ated by measuring the interaction of P11-SAP with dentin sur-faces (Fig 13) and by determining the degree of remineralization(Fig 14) Micro computed tomography (micro-CT) measurementsafter 40 days showed an increase of 68 in mineralization withP11 SAP formulation treatment compared to 20mineralizationof untreated lesion[36]

Beside the regenerative potential for dental hard tissue (den-tin) P11-SAPs promote additionally the formation of dental softtissue Periodontitis another major dental disease is character-ized by the destruction of tooth supporting structures (eg peri-odontal ligament)We are currently investigating if the propertiesof P11-hydrogels ndash the fast and tunable self-assembling processthe fibrillar architecture and its variable viscoelastic properties(Fig 15AndashC) ndash can be exploited to promote cell adhesion migra-tion proliferation and differentiation and thereby eventually sup-port restoration of damaged soft tissue[38ndash40] Human PeriodontalLigament Fibroblasts (HPDLF) expressed a stretched cell phe-notype with actin stress fiber formation after 24 h of culture onP11 hydrogels (Fig 15D) The metabolic activity rates of human

dental follicle stem cells (DFSC) on P11-4 hydrogels were com-parable to cells cultured on tissue culture polystyrene (TCPS)after 14 days Noticeably P11-4 hydrogels strengthen the osteo-genic differentiation of DFSCs compared with TCPS[39]

52 Nano-structured Mixed Mode Metal CatalystImmobilized on Self-supporting Carrier

Together with the Swiss Company SKANAG a new efficientcost effective nano-structuredmixedmode catalystmade ofmetalor metal oxides immobilized on a stable inorganic carrier was de-veloped for the production of new and improved design conceptof SKAN isolator systems Those isolators are sterilized throughthe usage of hydrogen peroxide However following a cleaningcycle it is mandatory to effectively remove and destroy remaininghydrogen peroxide Traditionally this is done by time-consumingflushing of the system with large amounts of air which is then re-leased directly into the environment More modern methods usecatalysts which decompose and destroy the hydrogen peroxideand such processes allow to recirculate the air into the buildingsaving time and energy consumption Previously such catalystswere applied to a compact carrier material

Scientists in the Pieles group at the School of Life SciencesFHNW developed a new process to coat a porous ceramic sub-strate in a batch process with metallic nano particles (Fig 16)This increased the available surface area tremendously and thusmultiplied the efficacy of the catalyst SKAN has successfullycommercialized this technology worldwide

53 SERS-based Imaging for the Detection ofGlioblastoma Tumor Cells during Surgery

A sharp delineation between tumor and healthy brain tissuefollowed by a complete tumor resection remains an unmet chal-lenge in high grade brain tumor as Glioblastoma (GBM) Imagingtechnologies are essential for preoperative planning and intraop-erative surgical removal of tumors nevertheless they do not al-low for visualization of residual tumor layers in the infiltrationzone[4142]To overcome this limit we use surface enhanced Ramanspectroscopy (SERS) in combination with the injection of tumorspecific functionalized gold nanoparticles (GNPs)[404344] Sinceabout 50 of GBM over express the epidermal growth factor re-ceptor (EGFR) anti-EGFR functionalized Raman active GNPswere developed The optical properties were further optimized bymodify GNPs with enhancing agents in combination with anti-EGFR functionalization this allows then a sensitive targeting oftumor cells (Fig 17 top) Hence the two functionalities on theGNP surface both strongly influence the method sensitivity eitherin terms of the amount of GNP on cells or the SERS signal inten-sity Unfortunately they are competitive thus the appropriate ratiofor high amount of cell binding GNPs and highest SERS signalhad to be elaborated Moreover a polyethylene glycol shell had

Fig 13 Interaction of fluorescent labeled P11-4 with human dentinsurface (A1) Artificial caries lesion of human dentin surfaces (A2)Confocal microscopy picture of artificial enamel lesions treated withfluorescence-labeled P11-4 (ATTO647-P11-4) after 1 day and 14 days(A3)

Fig 14 Remineralization of an artificial caries lesion after applicationwith a P11-4 formulation micro-CT Measurements were performed before(A1) and after application of P11-4 (A2 A3)

Fig 15 (A) P11-4-hydrogel prepared in a Tris-NaCl buffer (140 mM NaCl pH 72) after 2 hours of self-assembling (B) Nanofibrillar architecture ofa P11-4 hydrogel prepared for Scanning Electron Microscopy (C) Oscillatory rheology measurements of P11-4 hydrogels prepared in differentbuffers Storage modulus (Grsquo) has been used as parameter for stiffness (D) HPDLF after 24 h culture on P11-4 hydrogels Actin cytoskeleton hasbeen stained with rhodamine-conjugated phalloidin (red) cell nuclei were stained with DAPI (blue) Scale bar 100 microm


to be introduced to prevent unspecific interaction with other cellsThe specificity of GNPs binding was investigated in vitrowith hu-man GBM cells expressing high to low EGFR levels BS153 andU87MG respectively while mouse astrocytes IMA21 were usedas EGFR-negative cells Raman-active GNPs with no anti-EGFRwere used as further control An in depth characterization wasperformed to find the best parameters to ensure a distinct Ramandetection of GBM cells while minimizing non-specific binding

Raman analysis showed that anti-EGFR GNPs bound spe-cifically to the surface of the GBM cells with high affinity al-lowing for discrimination of tumor cells from the control cellsFurthermore a comparable high Raman signal intensity wasdetected among the different GBM cell lines depending on theexpression level of EGFR (Fig 17 bottom)

This work demonstrates in vitro that GNPs visualized withRaman imaging may be implemented intra operatively for im-mediate GBM-specific cell visualization improving the dismaloutcomes of patients

The research focus of the Laboratory of Nanochemistry of theSchool of Life Sciences of the FHNW led by Prof Dr PatrickShahgaldian is on the development of nanomaterials capable ofmolecular recognition and biocatalysis for a variety of applica-tions ranging from environmental bioremediation biotechnologyand biocatalysis to bio-analytics and nanomedicine representa-tive research results are highlighted hereinafter

54 Nanoparticles Supporting Bacteria Combating OilSpill Disasters

The KillmiddotSpill EU-supported project (Integrated biotech-nological solution for combating marine oil spills) focused onthe development of highly efficient economically and environ-mentally viable biotechnological solutions for the clean-up ofoil spills caused by maritime transport or offshore oil explora-tion and related processes Oil spills in marine environmentscause massive damage to marine ecosystems Besides possibletechnological solutions to recover spilled hydrocarbons scien-tists have also explored the potential of bacteria ubiquitouslypresent in marine environments capable of degrading oil hy-drocarbons (eg Alcanivorax Marinobacter PseudomonasAcinetobacter) It is established that the main limitation forthe efficient biodegradation of fuel-borne hydrocarbons is thelimited amount of necessary nutrients (mainly nitrogen andphosphorus) in seawater In order to tackle this limitation wehave developed a new class of porous nanomaterials capable tocarry nutrients (N amp P) in seawater and to release their contentwhen in contact with an oil phase Based on mesoporous silicananoparticles the nanomaterial developed allows retaining theencapsulated nutrients in aqueous media which in turn is re-leased in contact with an oil phase thus supporting bacterialdegradation of hydrocarbons[45]

55 In silica Protein Engineering From MolecularRecognition to Biocatalysis

In our efforts to develop recognition nanomaterials for largeprotein assemblies such as viruses we established a method to

Fig 16 Scanning electron microscope picture of the catalyst coatedsupport material Measured by Zeiss Supra SEM gold coated scalebar equals 10 microm

Fig 17 Top Schematic representation of Raman-guided surgery to differentiate brain tumor cells at the border of the cavity resection BottomOverlay images of brightfield and Raman mapping of anti-EGFR GNPs incubated with EGFR negative (A) and EGFR positive cells with low (B) andhigh (C) EGFR expression level respectively The brighter the color the higher the number of GNPs attached to the cells


create molecular recognition imprints of non-enveloped icosahe-dral viruses at the surface of silica nanoparticles cf Fig 18[46]This method is based on surface imprinting using silica nanopar-ticles as carrier material and organosilanes serving as buildingblocks to produce a virus recognition layer Following this proofof concept we adapted this chemical strategy to virus-like par-ticles[47] and implemented an internal enzyme-based detectionsystem allowing for label-free virus detection[48]

Enzyme immobilization and encapsulation represent estab-lished strategies to retain enzymatic activitywhile improving theirstability against physicochemical stress conditions Building up-on our findings on virus imprinting we have developed the con-cept of supramolecular enzyme engineering which in contrastto enzyme engineering does not require genetic manipulation orcovalent modification of the enzymeWe have demonstrated thatenzymes when immobilized at the surface of silica and shieldedin a soft organosilica shell retain their enzymatic activity witha drastic improvement of their stability against external stressconditions[49] In the same context we also demonstrated thatenzymendashpolymer conjugates can be attached in a stable yet re-versible fashion on polymeric filtration membranes exploitingsurface supramolecular interactions[50] The commercial imple-mentation of the enzyme protection technology developed is nowcarried out by INOFEA AG a biotech company that spun-offfrom the activities of our laboratory

56 Two‐dimensional MetalndashOrganic orSupramolecular Networks

Self-assembled networks featuring nanometer-sized poresand long-range crystallinity provide configurable templatesfor hostndashguest recognition and site-specific chemistry and mayimpact several technological applications provided that theresulting material is of sufficient stability We have recentlydemonstrated that calixarene-based amphiphiles when bear-ing suitable chemical moieties can self-assemble as stable andcrystalline 2D networks For example working on the self-as-sembly of a carboxylate-modified calix[4]arene at the airndashwaterinterface we demonstrated that the presence of Cu2+ transitionmetal ions in the water phase causes the formation of crystal-line and stable 2D metal organic network which can be fur-ther transferred on solid surfaces using the Langmuir-Schaeffermethod[51]An analogue of this amphiphile bearing cyano func-tions at the para rim was shown to form 2D crystalline layersthe self-assembly has been shown to be driven by the formationof a network of concerted dipolendashdipole interactions (Fig 19)We demonstrated that in spite of the limited energy of dipolendashdipole interactions the stability of the layer was sufficient toallow producing free-standing layers[52] This opens up new

perspectives in the use of such self-assembled films as supportsurfaces for advanced electron microscopy methods and singleparticle X-ray analyses

Received June 13 2019

[1] Y Mongbanziama SAeby M Kaehr V Pilloud J-L Robyr B MassereyS Hengsberger S Roth P Brodard Chimia 2016 70 649

[2] P Morel KunststoffXtra 2015 3 34[3] J Gonthier MSM Le mensuel de lrsquoindustrie 2015 4[4] P Morel KunststoffXtra 2016 9 30 [5][5] P Brodard Symposium on Thermal Analysis and Calorimetry of the

Romanian Academy Timisoara (Romania) May 2019 Plenary Talk[6] S C Jambagi S Kar P Brodard P P Bandyopadhyay Materials and

Design 2016 112 392[7] B Das P Brodard PP Bandyopadhyay lsquoRaman Spectroscopy assisted

residual stress measurement of plasma sprayed and laser remelted zirconiasplats and coatingsrsquo in preparation

[8] R Hartmann R Hany E Pletscher A Ritter B Witholt M ZinnBiotechnol Bioeng 2006 93 737

[9] M Zinn H UWeilenmann R Hany M Schmid T Egli Acta Biotechnol2003 23 309

[10] R Hany R Hartmann C Boumlhlen S Brandenberger J Kawada C LoumlweM Zinn B Witholt RH Marchesault Polymer 2005 46 5025

[11] S Z Tan C R Reisch K L J Prather J Bacteriology 2018 200 e00575[12] S Le Meur M Zinn T Egli L Thony-Meyer Q Ren Microb Cell

Factories 2013 12[13] K Matsumoto S Taguchi Kobunshi Ronbunshu 2011 68 271[14] C Hori T Yamazaki G Ribordy K Takisawa K Matsumoto T Ooi M

Zinn S Taguchi J Biosci Bioengin 2019 127 721[15] S Follonier M S Goyder AC Silvestri S Crelier F Kalman R Riesen

M Zinn Int J Biol Macromol 2014 71 42[16] S Follonier R Riesen M Zinn Chem Biochem Engin Quart 2015 29

113[17] S Karmann S Follonier D Egger D Hebel S Panke M Zinn Microb

Biotechnol 2017 10 1365[18] S Karmann S Panke and M Zinn Front Bioengin Biotechnol 2019 7[19] E Carrentildeo-Morelli M Zinn M Rodriguez-Arbaizar M Bassas lsquoNickel-

free P558 austenitic steel parts processed from metal powder-PHAbiopolymer feedstocksrsquo httpswwwepmacompublicationseuro-pm-proceedingsproductep150517

[20] E Carrentildeo-Morelli M Zinn M Rodriguez-Arbaizar M Bassas H GirardT Chappuis J Richard lsquoMIM of nitrogen-strengthened austenitic stainlesssteel using biopolymer-based binderrsquo httpswwwepmacompublicationseuro-pm-proceedingsproductep16-3297417

[21] C Tematio M Bassas-Galia N Fosso V Gaillard M Mathieu M ZinnEM Staderini S Schintke lsquoDesign and characterization of conductivebiopolymer nanocomposite electrodes for medical applicationsrsquo MaterialsScience Forum Vol 879 pp 1921-1926 2017 httpsdoiorg104028wwwscientificnetMSF8791921

[22] S Laternser H Keller O Leupin M Rausch U Graf-Hausner MRimann SLAS Technol 2018 23 599 DOI 1011772472630318776594

[23] K Siegmann J Inauen D Villamaina M Winkler Appl Surf Sci 2017396 672 DOI 101016japsusc201611007

Fig 18 Schematic representation of the virus imprinting method (left)and representative scanning electron micrographs of the nanosystemsproduced Scale bars represent 100 (top) and 20 (bottom) nm

Fig 19 Molecular resolution atomic force micrographs of asupramolecular organic network of p-cyano-calix[4]arene produced atthe air-water interface and transferred on a silicon dioxide substrateusing the Langmuir-Schaeffer method (A amp B) and molecular model ofthis supramolecular network (C)


[24] K Siegmann J Inauen R Sterchi M Winkler Surf Interface Anal 201850 205 DOI 101002sia6359

[25] T Franken A Heel Chem Ing Tech 2018 90 1157 DOI 101002cite201855054

[26] C Kang A Honciuc ACS Nano 2018 12 3741 DOI 101021acsnano8b00960

[27] D Wu A Honciuc ACS Appl Nano Mater 2018 1 471 DOI 101021acsanm7b00356

[28] D Wu V Mihali A Honciuc Langmuir 2019 35 212 DOI 101021acslangmuir8b03342

[29] P Woodtli S Giger P Muumlller L Saumlgesser N Zucchetto M J Reber AEcker D Bruumlhwiler Dyes and Pigments 2018 149 456 DOI 101016jdyepig201710029

[30] N Zucchetto D Bruumlhwiler Chem Mater 2018 30 7280 DOI 101021acschemmater8b03603

[31] FDeuberCAdlhartChimia201771 236DOI102533chimia2017236[32] S Zhao O EmeryAWohlhauser M M Koebel CAdlhartW J Malfait

Materials amp Design 2018 160 294 DOI 101016jmatdes201809010[33] F Deuber S Mousavi L Federer C Adlhart Adv Mater Interfaces 2017

4 201700065 DOI 101002admi201700065[34] S Mousavi F Deuber S Petrozzi L Federer M Aliabadi F

Shahraki C Adlhart Colloids Surf A 2018 547 117 DOI 101016jcolsurfa201803052

[35] F Deuber S Mousavi L Federer M Hofer C Adlhart ACS Appl MaterInterfaces 2018 10 9069 DOI 101021acsami8b00455

[36] J Banerjee E Radvar H S Azevedo lsquoSelf-assembling peptides andtheir application in tissue engineering and regenerative medicinersquo inlsquoPeptides and Proteins as Biomaterials for Tissue Regeneration andRepairrsquo Eds M A Barbosa M C L Martins Woodhead Publishing2018 p 245-81

[37] L Kind S Stevanovic S Wuttig S Wimberger J Hofer1 B Muumlller UPieles J Dent Res 2017 96 790

[38] F Koch M Muumlller F Koumlnig N Meyer J Gattlen U Pieles K Peters BKreikemeyer S Mathes S Saxer R Soc Open Sci 2018 5 171562

[39] F Koch A Wolff S Mathes U Pieles S Saxer B Kreikemeyer KPeters Int J Nanomed 2018 13 6717

[40] F Koch K Ekat D Kilian T Hettich O Germershaus H Lang KPeters B Kreikemeyer Adv Healthcare Mater 2019 DOI101002adhm201900167

[41] M Jermyn K Mok J Mercier J Desroches J Pichette K Saint-ArnaudL Bernstein M-C Guiot K Petrecca F Leblond Sci Transl Med 20157 274ra19

[42] C G Hadjipanayis G WidhalmW Stummer Neurosurgery 2015 77 663[43] H Karabeber R Huang P Iacono J M Samii K Pitter E C Holland M

F Kircher ACS Nano 2014 8 9755[44] M F Kircher A de la Zerda J V Jokerst C L Zavaleta P J Kempen

E Mittra K Pitter R Huang C Campos F Habte R Sinclair C WBrennan I K Mellinghoff E C Holland S S Gambhir Nat Med 201218 829

[45] N Corvini M El Idrissi E Dimitriadou P F-X Corvini P ShahgaldianChem Commun 2019 DOI 101039c9cc02801c

[46] A Cumbo B Lorber P F X Corvini W Meier P Shahgaldian NatCommun 2013 4 1503

[47] S Sykora A Cumbo G Belliot P Pothier C Arnal Y Dudal P F XCorvini P Shahgaldian Chem Commun 2015 51 2256

[48] S Sykora M R Correro N Moridi G Belliot P Pothier Y Dudal P F-X Corvini P Shahgaldian ChemBioChem 2017 18 996

[49] M R Correro N Moridi H Schuumltzinger S Sykora E M Ammann EH PetersY Dudal P F-X Corvini P Shahgaldian Angew Chem Int Ed2016 55 6285

[50] N Moridi P F-X Corvini P Shahgaldian Angew Chem Int Ed 2015127 15013

[51] M Moradi L G Tulli J Nowakowski M Baljozovic T A Jung PShahgaldian Angew Chem Int Ed 2018 56 14395

[52] M Moradi N L Opara L G Tulli CWaumlckerlin S J Dalgarno S J TeatM Baljozovic O Popova E van Genderen A Kleibert H Stahlberg J PAbrahams C Padeste P F-X Corvini TA Jung P Shahgaldian Sci Adv2019 5 4489


laboration with institute iPRINT of HEIA-FR) drug delivery andtissue engineering application (Fig 1 right)

The ChemTech Institute in collaboration with the PlasticInnovation Competence Center PICC in Fribourg participatesin the European project BIOSMART for the development ofnovel bio-based packaging applications (biosmart-projecteu)In our labs we are working on polyester amide block poly-mers which are fully bio-sourced and biodegradable By vary-ing the chemical structure ndash the hard and soft segment ndash wecan fine-tune and adjust the physico-chemical mechanical andbarrier properties Scale-up studies with kneader reactors byLIST Technology AG are under way to prepare larger quan-tities and evaluate the industrialization of these biopolymersBeside these polyester amides the institute ChemTech workson polylactic acid (PLA) especially in the synthesis of the lac-tide monomer and its reactive extrusion via ring opening po-lymerization (ROP) as a sustainable process

The ChemTech Institute is also active in material recyclingprojects some of which are carried out in collaboration with de-veloping countries In a recent project involving partners in sub-SaharanAfrica the group developed and optimized an innovativemethod of recycling used vehicle tires into versatile rubber tilesThe technique consists of grinding the tires into rubber particlesseparating out the tissue and metal components and condition-ing the particles to form tiles that can be used for flooring orinsulation purposes The novelty of the approach is that no glueor binder is needed in the process making the technique cheapersafer and more widely accessible

One of the biggest challenge of plastics industries is to predicthow the material will age Indeed extremely various applica-tions expose the base polymers to strong temperatures variationssunlight air aggressive chemicals etc all contributing to theirdegradation Base material suppliers provide indications of age-ing based on standardized tests but application industries areproducing final objects exposed to non-constant environmentalstresses often for much longer times than advised by the basematerial suppliers In order to help these companies producingfinal polymer-based products several publicndashprivate researchprojects have been carried out at HEIA-FRChemTech In col-laboration with major industrial partners of the Fribourg regionproducing polymer goods ranging from water tubes to automo-tive components and electric connectors the research team ledby Prof Dr Pierre Brodard selected the most appropriate char-acterization methods[1]

In 2014ndash2015 the POLYAGE project focused on chemicalageing of polyethylene- and polyamide-based plastics (PE andPA)[23] New samples were first fully characterized by differen-tial scanning calorimetry thermogravimetric analysis infraredand Raman spectroscopy and scanning electron microscopyThen the samples were exposed to various temperature programsto force their degradation and compared to aged products pro-vided by our industrial partners As expected PE-based materi-als are chemically decomposed by oxidation which was easilyconfirmed by spectroscopy and we were able to quantify thekinetics of oxidation by chemiluminescence thus allowing an

exact prediction of the lifetime of the samples at any temperatureOn the other hand PA-based materials did not seem to changetheir chemical composition even though their mechanical integ-rity was strongly fading during ageing their infrared and Ramanspectra were almost unaffected Indeed the fracture toughnessmeasured by tensile tests was reduced by 40 in the hardestconditions (20 days at 200 degC) but the composition remainedthe same We then found out that the structure of the materialhad changed SEM images revealed a highly inhomogeneousdispersal of the glass fibers in the reinforced PA-based samplesafter thermal ageing which probably accounts for their apparentfragility (Fig 2)

As a logical next step we decided to concentrate on physi-cal ageing in the follow-up project POLYLIFE in 2015ndash2016[4] By physical ageing we mean no change in the chemicalcomposition but a modification of the structure like the above-mentioned alteration of the glass fibers distribution in the PAmatrix For this purpose and with the strong support of ourmechanical engineering department a new method based onultrasound was developed a piezoelectric transducer generatesultrasonic waves in the sample and an interferometric laserhead is used for detection Two implementations have beendevised ultrasonic Lamb waves propagating in the plane ofa thin flat sample and mapped by the scanning laser head al-lowing determination of the elastic modulus of the material indifferent directions and resonance of ultrasonic frequenciesthrough the sample enabling to measure more complicatednon-flat objects (Fig 3)

These two non-destructive techniques are sensitive to anymodification of the physical structure even on final industrialproducts Both approaches are in excellent correlation with me-chanical properties obtained by macroscopic (tensile test) andmicroscopic (nanoindentation) methods For the PA-based sam-ples exposed to several temperature programs (160 degC to 270 degC30 h to 3000 h) we found out a temperature-dependent exponen-tial decay of the fracture toughness with time Based on theseresults we were able to calculate the kinetics parameters andpredict their lifetimes

Recently we investigated the recycling process of a high-performance engineering polymer Small parts produced withthis material generate a significant quantity of offcuts (~60)that must be reprocessed (Fig 4) to be re-useable for furtherproduction an operation inducing a large thermal load on thepolymer[5]

We found out that the chemical stability is proved up to 3 cy-cles of re-extrusion under inert atmosphere but that theYoungrsquosmodulus slightly decreases due to a decrease in the length of thereinforcing glass fibers observed during the recycling process bymicro CT-scan However the decisive element to assert whetherthe recycled material is suitable or not is to test it on parts inproduction at the industrial level a process now in progress inthe companies

Fig 1 The novel dental material lsquoSAREMCO APT ndash Advanced PolymerTechnologyrsquo with improved biocompatibility (left) and hydrogel materials(right)

Fig 2 SEM images of PA before (a) and after (b) thermal ageing at200 degC for 20 days






















2was produced that



2 H

2 This CO

2negative



















2into energy


based on CoAl2O


secondary CoAl2O



xO

4supported catalyst





































































































































2was produced that



2 H

2 This CO

2negative



















2into energy


based on CoAl2O


secondary CoAl2O



xO

4supported catalyst




























































































































2was produced that



2 H

2 This CO

2negative



















2into energy


based on CoAl2O


secondary CoAl2O



xO

4supported catalyst





























































































































2into energy


based on CoAl2O


secondary CoAl2O



xO

4supported catalyst


































































































































































































































































































































































































































































































































































Documents

FH Universities of Applied Sciences HES Fachhochschulen – … · 2019. 8. 30. · Universities of Applied Sciences Fachhochschulen – Hautes Ecoles Spécialisées FH HES Materials