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Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
Textile sensors & actuatorsDr. Cédric Cochrane
ENSAIT / GEMTEX, 2 Allée Louise et Victor Champier, 59056 Roubaix, France
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
L’ensait
EnsaitFrench « Grande école » funded in 1889
• 120 students graduate each year
• Partnerships with 43 universi/es and more than 250 companies
around the world
2
• Funded in 1992
• 40 researchers (8 Full professors)
• 20 PhD Students
Gemtex (Lab of Ensait)
Ensait presentation
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
3 Research groups
Group Multifunctional
Textiles and Processes
MTP
Group Mechanics
Textile Composites
MTC
HCD
Group Human
Centered Design
HCD
3
Melt spinning, coating, surface modification (plasma)microencapsulation, flame retardantSensing materials for smart textileWeaving, knitting, nonwoven…
Modeling of weaving, knitting, braiding processes…Deformation of dry preform (modeling and sensors integration)
Confection of garment in 3DFast prototyping, supply chain managementSensorySmart textile acceptability
Director: Prof. Vladan Koncar
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
Outline• Sensors
– Mechanical sensors
– Temperature sensors
– Solvent sensors
• Actuators
– Electrochromic textile
– Light emitting fabric
• Perspectives
4
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
Sensors: base material
• CPC: Conductive Polymer Composite
5
No conductive networks: Insulator
Conductive network: Conductive
Conductive filler + polymer matrix (insulator)
Percolation threshold
Filler : Carbon Black, Carbon nanotube, Silver, Intrisic Conductive Polymer etc…
Polymer matrix : PE, PP, Polysiloxane, Latex, EVA…
Specific conductive behavior
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
Sensors: base material• Near the percolation threshold:
6
R = ρ × L / S
Length and section area (CHANGE)
CONSTANT
Electrical resistance (1/x variation)
• Example: Mechanical sensor
Exacerbated conductivity variation !
Very high slope
“Good” conductivity
ME
TALS
Strong variation !Change with volume
Change (like metal)C
PC
s
R0 R1Stretching
SL
Piezoresistive behavior
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 7
Preparation of CB based Piezoresistive CPC:
Elastic polymer matrix + Conductive fillers
ThermoPlasticElastomer (TPE)
Evoprene 007 (S-B-S)
=Highly Structured Carbon Black
(HSCB)
Degussa Printex (20-200nm)
=
(chloroform)Solvent mixing
Fabric Coating
Sensors: development of mechanical sensor
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 8
Realization of conductive track on fabric (selective coating):
Fabric (parachute):PA6.6 HT
42 g/m²45 µm
2.5 mm
100 mm
Mask : Thickness 110 µm to 200 µm Shape :
High Length / width ratio (increase piezoresistive behavior)
After mask removing
Drying: 30 min max.
Thickness ≈ 16 µm110 µm mask
-10
0
10
20
0 2 4 6 8 10 12
Hei
ght (
µm
)
x (mm)
Sensors: development of mechanical sensor
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 9
Electrical connections and protective layer
Stainless Steel wire + CPC drop 550 fibres x 12 µm
+ Protective Latex layer Spraying + Mask
Final sensor on Nylon fabric
Light Flexible Substrate non-affected
Sensors: development of mechanical sensor
45 µm total thickness
Electrical connection = critical
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
• Electromechanical behavior: Gauge factor (K)
10
0
5
10
15
20
25
30
35
0 0,05 0,1 0,15 0,2 0,25 0,3 0,35 0,4 0,45 0,5
Rn
(Ω/Ω
)
Elongation ε (mm/mm)
• Measurement until break ε=45%• High K = 66 (max. 2 for metal Gauge)• Non linear behavior :
Weak variation (< 5%) of R between-20°C et +50°C
Sensors: development of mechanical sensor
ε∆∆
= nm
RK
• Thermal dependence
K
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
Classical gauge on metallic part of suspension line
Sensors connection
• Application: In-situ measurement on parachute canopy during inflation
11
Red: Sensor in weft directionBlue: sensors in wrap direction
∆L/L % max
(weft)
∆L/L % max
(wrap)
(1.55 ± 0,23) % (1.70 ± 0,23) %
Sensors: development of mechanical sensor
Example, test on a model
Sen
sors
x2
Recorded data during inflation
Blue
Red
Green: Classical gauge
Good fit between data:-From classical gauge and our gauge-From modeling and our gauge
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
• Application: elongation sensor for stratospheric balloon
12
Study for the French space agency
Developed sensor: PEDOT / Latex and PEDOT / Polysiloxane
Main problems for this development : Thickness of support (25 µm) extreme temperature (-90 °C) and large dimension
Balloon:• 1.2 106 m3 volume• 130 m of diameter• 5.5 ha surface
K0-20% ≈ 4
Measurement above 50 % of elongation
• Temperature characterization• Design optimization
In progress:
A. El-ZeinC. Cochrane
Sensors: development of mechanical sensor
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 13
N. TrifignyF. BoussuNumtiss Project
Sensor CPC: CB/ latex & PEDOT / latex, glass (300 tex)
Project aim: optimization of process and preservation of material health
Sensors: development of mechanical sensor• Application: In-situ measurement during weaving process of glass fibre
Development of yarn sensor by coating
Observation:• lot of friction• lot of break fibre
Fall of mechanical properties of composite structure
Copper wire
Sensing part
Glass fibre
Main interest: Sensor is supported by glass fibre
500 fps
Why these measurements?
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 14
N. TrifignyF. BoussuNumtiss Project
Sensors: development of mechanical sensor• Application: In-situ measurement during weaving process of glass fibre
Characterization Gauge factor (K) ≈ 2 (Less than expected)
Integration to weaving process
In-situ measurement
Sensor after wrap stop motion and before heald
Integration is correct
Frame movement are visible on recorded data
500 fps
2,4 s Frame down
Frame up
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 15
+
CNT and polymersyarn
Sensors integrated in
fabric
Connected fabric
Sensors in fireman suit
Example: temperature sensors for firemanAim of system: increase security, help fireman to detect high temperature before accident
Melt mixing and meltspinning
A. CaylaInteltex project
Sensors: development of temperature sensor
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 16
Log
rési
stiv
ité ρ
(Ω
.m)
Temperature (°C)
ρ0
ρmax
PTC effect
NTC effect
PTC = Positive temperature coefficient
NTC = Negative temperature coefficient
Principle of this technology
Due to thermal transition
(expansion) of polymer
Modification of conductive network
Detected temperature could be chosen by polymer selection
A. CaylaInteltex project
Sensors: development of temperature sensor
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 17
58°°°°C
Sensors: development of temperature sensor
Results
For fireman application we chose polymer with thermal transition at 58°C
Reliability of detection (multicycle) Sensors yarns
Fireman suit
Good integration to suit
A. CaylaInteltex project
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 18
Chemical sensor able to detect vapor or liquid
PVC effect is due to expansion of polymer matrix by solvent absorption
NVC effect is due to evaporation of solvent
Rés
istiv
ité (
ohm
.m)
Introduction of solvent vapor
NVC effectPVC effect
Time (s)
Sensors: development of solvent sensor
Works only if chemical is solvent of polymer matrix(As temperature detection we can choose polymer according to goal)
A. CaylaInteltex project
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
0 0S ( R R ) R= −
0 300 600 900 1200 1500 1800 2100
0,00
0,05
0,10
0,15
0,20
0,25
0,30
Toluene THF Chloroform MeOH
Sen
sitiv
ity
Time [s]
Monofilament PLA-/ 4 % CNT
19
Sensors : development of solvent sensor
Results (for PLA/CNT yarns)
-4
-3
-2
-1
0
1
2
0 100 200 300 400 500
Sen
sibi
lité
Temps (s)
Sensibility definition
Moisture detection
Other solvent: Toluene, Chloroform…
Good detection (response time and repeatability) for some solvent (including water)
A. CaylaInteltex project
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
• Possibility to design:
– Mechanical sensor for yarn or textile structure
– Temperature sensor to detect one temperature
– Chemical sensor to detect some solvent
20
Development of sensor: conclusion
• For:
– Aeronautic application
– Composite
– PPE and security
– Other ?
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
Actuator: Electrochromic textile
21
Electrochromic ?: Color changing with electric stimuli
F.M. KellyIntellitex project
Involves electroactive materials that present a change in optical
properties when the material is electrochemically oxidized or reduced.
The colour change is reversible .
Reduction (gain e -)
Oxidation (lose e -)Electronic state 1
Colour 1Electronic state 2
Colour 2
Oxidant + e - Reductant
Existing product : between glass or polymer film
Substrate
Conductive layer
Ion Storage
Electrolyte
Electrochromic product
Transparent conductive layer
Substrate
+
-
Traditional 7-layers ECD structure:
2 states are stable
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
Actuator: Electrochromic textile
22
Simplification of structure: 7 layers to 3 layers (with mixing of components)
PET fabric functionalized with PEDOT
PET fabric + solid electrolyte
PET-ITO4.5 V
F.M. KellyIntellitex project
Aim of project: development of an electrochromic textile structure
Active layerIn-situ polymerization
Benefits
Fast switching times
Good cycling (>>50)
Problems with liquids reduced due to
high viscosity of electrolyte
Drawbacks
Consistency of colour
Saturation
Air bubbles under PET-ITO film
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 23
F.M. KellyIntellitex project
Actuator: Electrochromic textileOther colors ?
We can choose the monomer to dispose of numerous colors
In reality it is not so easy !
Consistency of colour is not goodPET/ITO not textile !
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 24
F.M. KellyC. MorettiHomotextilus project
Actuator: Electrochromic textileLatest results (September 2014)
Simplification of structure: 2 layers (textile + mixing of components)
More flexible (no PET-ITO film)Only 2 colors (for the moment)
Aim of project: Develop an electrochromic shirt to study human interaction (social network, serious game etc…)
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 25
Actuator: Light emitting fabric
Application to Photodynamic Therapy (PDT)
What is Photodynamic Therapy (PDT)?
• PDT involves 3 individually “non-toxic components” that are
combined to induce cellular effects
PHOTOSENSITIZER : photosensitive molecule (drug) that localizes on a target cell
LIGHT of a specific wavelength that activates the sensitizer
The photosensitizer absorbs light and reacts with OXYGEN to generate reactive
oxygen species (singlet oxygen, toxic for cell)
Curing of cancer or pre-cancer cells
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 26
Actuator: Light emitting fabric
• A homogeneous and reproductible fluence rate delivery during clinical PDT plays
a determinant role on efficiency
Currently, in dermatology, rigid LED panels or OLED patch are used
• Different shape• Different size• Different color (often blue or red)
Light treatment problem
Ambulight
Ambulight vs. led panel
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 27
Actuator: Light emitting fabric
3 major problems of actual treatment
1 ) Size of illumination area
Ambulight: Ø <2 inches (5 cm) not suitable for large area treatment (scalp) and treatment of invisible (too small) lesion
2 ) Poor flat homogeneity
Aktilite CL 16
Moseley H. Light distribution and calibration of commercial PDT LED arrays. Photochem Photobiol Sci. 2005 Nov;4(11):911-4.
Some studies show that for a LED panel variation of power are 1 : 4
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 28
Actuator: Light emitting fabric3 major problems of actual treatment
3 ) Homogeneity loss due to projection on human body curves
Projection of flat source on curved surface is not optimal
Under treated (light dose not enough)
Over treated (light dose too strong)
The development of a flexible light source based on optical fibre would considerably improve the homogeneity of light delivery
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 29
Actuator: Light emitting fabricExisting POF structures to light emission
• POF weaving and abrasive treatment
Treated OF
Cladding 2 steps process• Weaving• Treatment
• Sanding• Solvent attack
Brochier Company
At the microscopic scale light spots are visible :• « Hot spots » dangerous for PDT
Used in fashion
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 30
Actuator: Light emitting fabricExisting POF structures to light emission
• POF Weaving in sandwich structure
Boeing CompanyLumitex Company
• Need layers (± rigid ) to• Homogenise light emission• Hold macrobending
Light emission is based on macrobending effect
If the bending angle is greater than a critical angle*
Side-emission effect
n1n2
*Critical angle = arcsin (n2/n1)
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 31
Actuator: Light emitting fabricOur Light Emitting Fabric (LEF)
POF Weaving without sandwich structure Flexible and conformable to the body
Samples:
20 cm (weft) x 15 cm (Wrap)
Weft: POF (250 µm)
Wrap: PES 330 dTex
• Satin 4
• Satin 6
• Satin 8
First try with simple weaving pattern
Light emission based on macrobending
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 32
Actuator: Light emitting fabricOur Light Emitting Fabric (LEF)
First results
Satin 4 Satin 8
• Emission of light !• Poor homogeneity along the fabric
To homogenize light emission:• Need optimization of weaving pattern (not simple weaving)• Need to put light source on the both side to compensate attenuation of emission along the fabric
POF Weaving without sandwich structure Flexible and conformable to the body
Light emission based on macrobending
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 33
Actuator: Light emitting fabricOur Light Emitting Fabric (LEF)
Inhomogene weave along sample to compensate the decrease of light emission
Sample:
21.5 cm (weft) x 5 cm (Wrap)
3 Areas:
• W1 designed from Satin 4 and 8
• W2 designed from Satin 6
• W3 designed from Satin 8 and 4
POF density: 37 cm-1
Patented
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 34
Actuator: Light emitting fabricOur Light Emitting Fabric (LEF): Production
• Hand weaving loom (firsts prototypes)
ARM B60, Biglen, Switzerland
• Dornier (Weaving gripper loom) (currently)
W1 W2 W3
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 35
Actuator: Light emitting fabricOur Light Emitting Fabric (LEF): Evaluation
Powermeter mapping Evaluation of flexibility
LEF of 107.5 cm² + 5 W Laser source
Average light emission:18.2 mW.cm-²Heterogeneity:2.5 mW.cm-²
13.7 %
Bend radius in weft direction: 5 mm
Good abilities: Possible use for PDT in dermatology
Large dimension > 100 cm² Flexible no addition of diffusive layer Low cost commercial PMMA POF
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 36
Actuator: Light emitting fabricOur Light Emitting Fabric (LEF)
Next steps: Clinical tests…treatment of vulval, and perianal areas?
We hope that our light Emitting Fabrics could be very soon proposed to deliver
ambulatory Photodynamic Therapy !
Flexitheralight Project (National)Phos-Istos Project (Europeen)
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 37
Development of actuators: conclusion
• Development on:
– Electrochromic textile with simple structure
– Homogene light emitting fabric based on POF
• For:
– Communicative textile, fashion, human behavior study
– Health and cancer treatment
– Other ?
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 38
Perspectives: Labs future work
Monitoring of composite structure: from weaving to end of life
• Sensors on glass fibre• Sensors on carbon fibre (aeronautic applications)• Long life sensors !• Problem with electrical connection !?
Light emitting fabric for PDT• Make larger LEF (for prophylactic action)• Make custom LEF for internal cancer (vulva, perineum…)
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 39
Perspectives: Labs future work
Energy harvesting
Multicomponents spinning
Core electrodeActive layer(Piézo)
External electrode
z
PVDFPVDFPVDFPVDFPVDFPVDFPVDFPVDFPolymerPolymerPolymerPolymer + + + +
conductiveconductiveconductiveconductive fillerfillerfillerfiller
European center of innovative textile, CETI)
Generate electricity from textile vibration (?)
Applications in outdoor textile, composite panel, wearable technologies etc…
F. rault
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan) 40
Thank you for your attention
Cédric Cochrane – Oct. 2nd, 2014, TIFE 2014, Taipei (Taiwan)
Bibliography
• Mechanical sensors
– Sensors 2013, 13(8), 10749-10764; doi:10.3390/s130810749
– Sensors 2010, 10(9), 8291-8303; doi:10.3390/s100908291
– Sensors 2007, 7(4), 473-492; doi:10.3390/s7040473
• Temperature and chemical sensors
– Sensors and Actuators B: Chemical Volume 160, Issue 1, DOI: 10.1016/j.snb.2011.07.004
– Synthetic Metals, Volume 161, Issues 11–12, DOI: 10.1016/j.synthmet.2011.03.012
• Electrochromic textile
– Displays, Volume 34, Issue 1, DOI: 10.1016/j.displa.2012.10.001
– IJFTR Vol.36(4) [December 2011], pp 422-428
– IJFTR Vol.36(4) [December 2011], pp 429-435
• PDT
– Materials Science and Engineering: C, Volume 33, Issue 3, DOI: 10.1016/j.msec.2012.12.007
41