dr. cédric cochrane · cédric cochrane – oct. 2 nd, 2014, tife 2014, taipei (taiwan) textile...

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

[email protected]


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


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


Outline• Sensors

– Mechanical sensors

– Temperature sensors

– Solvent sensors

• Actuators

– Electrochromic textile

– Light emitting fabric

• Perspectives

4


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


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


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)



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


45 µm total thickness

Electrical connection = critical


• 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


ε∆∆

= nm

RK

• Thermal dependence

K


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) %


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


• 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



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?


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


+

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


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




58°°°°C


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



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)



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)



• 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 ?


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


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


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



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 !


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…)


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



• 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



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


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


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


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)


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



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



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


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


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



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)


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 ?


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…)


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


Thank you for your attention

[email protected]


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

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dr. cédric cochrane · cédric cochrane – oct. 2 nd, 2014, tife 2014, taipei (taiwan) textile...

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