Lecture 7 Hybrid POSS Materials

Class 1C Organic phase is made in situ in the inorganic phase. and D: Small organic phase

dispersed in continuous inorganic phase

Class I

No chemical bond between

components

only weak interactions

(van der Waals, hydrogen,

electrostatic)

Class IIChemical bonds between

componentsstrong interactions(covalent bonds)

Entrapping GraftingJ. Livage

Just a reminder:

Making Hybrid Materials: Class 1C(Polymerizing in pores)

•Porous metal oxide•Liquid monomer (no solvent) •UV, heat, radiation

R

R

R R

RR

R

R

R

R

R R

RR

R

R

R

R

R R

R

R R

R

R

R

RR

R

R

RR R

R

RR

R

RR

catalyst

Non-porous composite material

Making Hybrid Materials: Class 1C(Polymerizing in pores)

1) Monolithic inorganic Polymer nanocomposite from completely filling pores2) Reinforced xerogel or aerogel by coating aggregated particles with polymer3) Polymerizing intercalated monomers in clay 4) Polymer surrounding colloid crystal of inorganic

First example: Monolithic inorganic Polymer nanocomposite from completely filling pores

• Infiltration & polymerization of monomer in pores of gel

• Provides a percolating filler phase based on the original gel skeleton

Acc. Chem. Res., 2007, 40 (9), 810–818

First example: Monolithic inorganic Polymer nanocomposite from completely

filling pores

Pope, E. J.; Asami, M.; Mackenzie, J. D. Transparent silica gel–PMMA composites J. Mater. Res. 1989 4 4 1018

Transparent, tough, tailorable refractive index, abrasion resistant

Reinforced xerogel or aerogel by coating aggregated particles with polymer

Porous materials, like aerogels, are super thermal insulation, but very weak

Monomers, such as superglue, can be polymerized directly on surface by chemical vapor deposition

Boday, D. J.; Stover, . J.; Muriithi, B.; Keller, M. W.; Wertz, J. T.; DeFriend Obrey, K. A.; Loy, D. A. ACS Applied Materials & Interfaces 2009, 1(7), 1364.

Reinforced xerogel or aerogel by coating aggregated particles with polymer

Epoxies, urethanes, some vinyl polymers

monomers can be polymerized in solution if they will precipitate onto the particles surfaces.

Acc. Chem. Res., 2007, 40 (9), pp 874–884

Polymer-Clay Nanocomposites from intercalation & polymerization of

monomers

A. Usuki, Y. Kojima, M. Kawasumi, A. Okada, Y. Fukushima,T. Kurauchi, O. Kamigaito, "Synthesis of nylon 6-clay hybrid," J. Mater. Res. 1993, 8, 1179

1) First heat 100 g montmorillonite (MMT) with 51.6 g of aminolauric acid and 24 mL conc. HCl in 10 Liters of water for 10 min.2) Filter, was 3X with 10 L hot water, then freeze dry, then dry under vacuum at 100 °C to afford ion exchanged, intercalated MMT3) Mix 29.7 g intercalated MMT, 509 g caprolactam, and 66 g 6-aminocaproic acid were mixed in mortar in pestle.4) The mixture was polymerized in3000 mL round bottom flask with mech. Stirrer and under nitrogen for 30 min at 100 °C then for 6 h at 250 °C. 5) The products were crushed in mortar & pestle, then washed with water and dried at 89 °C.

Polymer colloidal crystal nanocomposites

Microporous and Mesoporous Materials 2001,44-45, 227 - 239

1) Prepare a colloidal crystal (opal) from silica particles2) Add monomer & catalyst to fill pores3) Polymerize to form72% by volume silica filled organic polymer4) Dissolve silica away with HF if inverse opal is desired

Class 1D: Small organic phase dispersed in

continuous inorganic phase

Making Hybrid Materials: Class 1D(encapsulation of small organics)

• Polymerize metal oxide around organic• pores must be small or leakage will occur•Solid state dye lasers, filters, colored glass•sunscreens•Biopolymers•Medicines•Living cells•Imprinting (artificial enzymes)

Class 1D: the organic dye is trapped within the silica network

Simple method for encapsulating dyes.

Easily recyclable colored bottles

J. Livage

Organic dyes in a silica matrix

fluorescence - laser - NLO - photochromism

J. Livage

nonlinear hybrid C60-silica coated lenses

Optical limiters

Absorption spectrum of the UV protecting film (1 µm) with and without the UV-absorber molecule (34 wt%).

Chem. Soc. Rev., 2007, 36, 1270-1281

Preventing UV-light damage of light sensitive materials using a highly protective UV-absorbing Hybrid (Class 1D) coating

Visible absorption spectra of Photosystem I entrapped in sol–gel at intervals during the aging process compared with the solution spectrum of the native preparation. The spectrum of a control gel without PSI that was aged for 29 days is also shown

H. O'Neill and E. Greenbaum, Chem. Mater., 2005, 17, 2654

Dyes are protected against photodegradation by Class 1D matrix

Fluorescent core–shell silica nanoparticles incorporating organic dyes with different spectral characteristics, covering the entire UV-vis absorption and emission wavelengths. (Reproduced from ref. 31, with permission. Copyright 2005 American Chemical Society.)

H. Ow, D. R. Larson, M. Srivastava, B. A. Baird, W. W. Webb and U. Wiesner, Nano Lett., 2005, 5, 113

Sol-gel encapsulation of drugs in silica particles using microemulsions

Water in oil emulsions

Chem. Soc. Rev., 2007, 36, 932-940

Enzymes in sol-gel

Requires mild sol-gel (pH 7) Enzymes remain active longer than when in waterSensors and catalysts Science 1992, 255, 1113– 1115

Cyctochrome C encapsulated in dry aerogels

Generally thought that water is needed for enzyme activityAerogels made with cytochrome C have remained activeNO sensors

Amanda S. Harper-Leatherman Langmuir, Article ASAP 2012

Chem. Mater., 2005, 17 (10), pp 2654–2661

Bio encapsulation: Photosynthesis system

Enclapsulation of liposomes in silica gel

Langmuir, 1997, 13 (19), pp 5049–5053

Bacteria encapsulated within a silica matrix aged for (a) 1 month without glycerol and (b) 1 day with a layer of glycerol.

Encapsulating living cells in silica

Imprinting to make synthetic enzymes in hybrid materials

Chem. Mater., 2003, 15 (19), pp 3607–3613

Imprinting dopamine analogs into silsesquioxane modified silicas for sensors

Imprinting DDT into silsesquioxane modified

silicas for sensors

C. Lin, A. Joseph, C.K. Chang, Y.C. Wang, Y.D. Lee Anal. Chim. Acta, 481 (2003), p. 175

Imprinting Caffeine into silica modified with silsesquioxane with non-bonding interactions

C.W. Hsu, M.C. Yang, J. Non-Cryst Solid, 354 (2008), p. 4037

Imprinting dopamine analogs into silsesquioxane modified silicas for sensors

Acc. Chem. Res., 2007, 40 (9), pp 756–767

Imprinting that generates on optical signal when site recognizes molecule