Development of Smart Textiles

and Their Applications in

Wearable Electronics

Prof. Xiaoming Tao

The Hong Kong Polytechnic University

xiao-ming.tao@polyu.edu.hk

@2015 Textile International Forum and Exhibition, Taipei

Outline

• Introduction

• Types of Smart Textiles for Wearable Electronics (STWEs)

• STWE devices

• Application opportunities and issues

• Conclusions

Evolution of STWEsHandbook of smart textiles

2000 2005 2010 2015 2020 2025

Product entry to markets

To build nano- or micro-structures on the surface or inside fibers

To impart electronic or photonic functions into textile structures

To endure large deformation cycles

Advance Materials, 26(31):5310-53360, 2014

STWEs

1D Single Fiber/Yarn Based:

Fiber transistors: (a) fiber organic field-effect transistors, (b)

wire electrochemical transistors, (c ) supercapacitors

( c )

2D Fabric Based Capacitive cantilever though layer-by-layer screen printing

process

Fabric Antennas

• E-fiber antenna• textile triband

antenna• dual polarized

textile antennas• all textile

antenna• circularly

polarized antenna

8

Textile Mechanical Power Nanogenerator

(b) Two layers with seperators(a) Sandwich type

An output of 100 mWh is obtained by 20 minutes walking and 1 million loading cycles!

Energy & Environ. Sci. 2013 Energy & Environ. Sci. 2014

• memory device.

Fiber circuitry:

(a)A binary tree multiplexer constructed from WECTs and their dynamic electrical characteristics, (b) A woven inverter circuit and its dynamic electrical characteristics, (c) Fiber-based fabric-array

Three-dimensionally Deformable, Highly Stretchable, Permeable,

Durable and Washable Fabric Circuit Boards Royal Soc Proc. A, 470(2171), 2014472, 2014

Outstanding Performance and Washing-ability

0 200000 400000 600000 800000 1000000

3.00

3.02

3.04

3.06

3.08

3.10

After 1,000,000 cycles with 20% strain,

(Rmax

-Rmin

)/Rmin

*100%=0.65%

600000-600050 cycles

0-50 cycles

1000000-1000050 cycles

Resis

tan

ce (

Oh

m)

No. of loading cycles

0 10 20 30 40 50 1000000 1000020 1000040 10000603.00

3.02

3.04

3.06

3.08

3.10

0 5 10 15 20 25 30

0

20

40

60

80

100

Resis

tan

ce r

ete

nti

on

rati

o (

%)

No. of washing times

Normal: without bag

Normal: with bag

Delicate: without bag

Delicate: with bag

Textile-based sensors: (a) Fabric bio-potential electrode and its

SEM photo, (b) Pulse-driven fiber nanogenerator by ZnO

thin films grown around a carbon fiber as a strain sensor,

(c) Vibration sensor arrays of piezoelectric fibers in gloves for detection and suppression of Parkinson’s tremor in the hand,

(d) Carbon loaded elastomer sensorizedgarment for kinesthetic monitoring,

(e) Strain-gauge sensor based on the reversible interlocking of Pt-coated polymer nanofibres,

(f) Carbon nanotube strain sensor for human motion detection,

(g) Woven electronic fibers with sensing and display functions,

(h) In-shoe plantar pressure monitoring in daily activities by fabric pressure

sensors.

performance specification

Strain range 0-60%

Output voltage 10-36mV

Overload capacity 400%FSO

Linearity ±5%FSO

Repeatability ±5%FSO

Hysterisis ±5%FSO

Strain gauge factor 1-100

Working temperature

-10-60℃

Fatigue resistance >100000 cycles

Zero drift ±0.5% FSO/h

Output resistance 10-100 kΩ

Relaxation ±5% FSO/30min

0 10 20 30 40 50 60

0.00

0.05

0.10

0.15

Unloadin

g

Loading

Str

ess (

MP

a)

Strain (%)

0 10 20 30 40 50 6010

15

20

25

30

35

40

Unloadin

g

Loading

Re

sis

tan

ce

(kO

hm

)

Strain (%)

13

Quasi-static Performance Specifications of Fabric Strain Sensor

14

0.10.2

0.3

0.4

0.5

0.6

0

5

10

15

20

-3

-2

-1

0

1

23

Modeling Results

Experimental Results

Strain Rate=0.05/s

Strain Rate=0.5/s

Strain Rate=5/s

Strain Rate=20/s

Strain Rate=100/s

Strain Rate=1000/s

(R-R

0)/

R0

Lg(Stra

in R

ate)

Strain

电阻变化率与应变及应变率的关系

理论与实验对比Quasi-static response to strain and temperature

Dynamic response to strain and strain-rate

Coupled Thermoelectric Behavior Dynamic sensing behavior

Fabric Strain Sensors

Fabric Pressure SensorConversion Structures

0 200 400 600 800 1000-100

0

100

200

300

400

500

600

700

Calibration

#1 Force

#1 Resistance

Time (ms)

Fo

rce

(N

)

0

10

20

30

40

50

60

70

80

Resis

tance (

kO

hm

)

150 155 160 165 170-100

0

100

200

300

400

500

600

700

Calibration

#1 Force

#1 Resistance

Time (ms)

Forc

e (

N)

0

10

20

30

40

50

60

70

80t2

Resis

tance (

kO

hm

)

t1

Delta t~0.01ms

0 2 4 6 8 10

0

2

4

6

8

10

#5

45

Impact 1

Impact 2

Impact 3

Pre

ssu

re b

y F

PS

(M

Pa)

Pressure by load cell (MPa)

Excellent agreement with the load cell Impact Test Rig

Effects of position and shear

Test Results

Smart Materials @ Structures, 2014

Science Challenges

• Novel safe, efficient, stable and flexible electronic and photonic materials and composites

• Formation mechanisms and properties of functional structures in textiles

• Interface properties between the functional materials and fiber assemblies

• Coupled structural mechanics of TFE devices

16

Wearable training system for sportsman

Objectives• To design, fabricate, calibrate and evaluate wearable training systems for elite sportsmen• To study the relationships between the force generated and real-time physical

measurement data using the newly developed limb-gauge monitoring systems in isometric, isokinetic and isotonic modes

• To test a hypothesis that perimeter of limbs has a defined relationship with the force generated

Training Trial Protocol

Two kinds of training activities

Three kinds of data

Isometric

Isokinetic

EMG/Pressure

Torque

Perimeter

Biodex

Limb-gauge monitoring system

DTS EMG sensor/Flexiforce sensor

Biodex

18

Results of Data Analysis

Isometric: The relationships between

torque, EMG and upper arm perimetermeasured by LMS of subjects’ MVC(maximum voluntary contraction) in 45degree isometric test are both in goodagreement with the results reported in anindependent study in 2008[1].

[1]Shi J, Yong-Ping Z, Qing-Hua H, et al, IEEE Transactions on, 2008, 55(3): 1191-1198.

Isokinetic: Because elbow anglecontributes to upper arm muscledeformation, a curve-fitted relationshipbetween elbow angle and perimeter atflexion of Isokinetic test is obtained in orderto exclude the effect of elbow angle beforeanalysis of Isokinetic data. Good agreementhas been obtained.

20

Intelligent Footwear System for Continuous Dynamic Foot Monitoring

Measurement: Spatial and temporal plantar pressure distributions In-shoe temperature and humidity COP 3-axis accelerations

Foot information display for PC and smart phone

21

i-Shoe Clinical Trial – Diabetic Patients vs. Healthy Subjects

Foot dimension

measurement

Novel Emed Test Monofilament Foot photo

Corridor activity Stairs activity Slope activity

Monitoring by intelligent footwear system

Questionnaire

survey on

wearing

comfort

22

Clinical trial – Results of stairs activity

Peak Pressure in climbing up and climbing down stairs

between H and DM group in Mean (SD)

23

Regions with significant difference

between two groups in climbing up and

down slope (DM>H) : LS5,LS6,RS5

(lateral and central forefoot)

Clinical Trial Results: Regions with Significant Difference

Regions with significant difference

between two groups in climbing up and

down stairs (DM>H) : LS5,RS5

(lateral forefoot)

24

Case Study of High Risk Diabetic Patient

Diabetic neuropathic foot with right foot ulcer

and skin graft surgery several month ago.Subject Information: Male, 59 years old, 64 Kg, 167

cm height, shoe size of 42, foot length L23, R23, foot

width L2.5E R3E; BMI 23 kg/m2 no palntar callus,

SWM test fail to sense 10g: RS5, RS4 RS1 >10gSWM

failing

positions

Pressure

failing

positions

Discussions, pressure, sensation and risk

Smart Garments for Vehicle Crash TestTest samples: a pair of vest and shorts for dummy Hybrid III;

a piece of cushion for car seat

Pressure sensing element:

Vest: 2*5 shorts: 2*5 cushion: 14

Measuring range (linear): about 4MPa

Overload (non-linear): about 6MPa

Installation on dummy/seat/sled/crash test

27

Parameters 30km/h 40km/h

Uploading duration 10ms – 30ms

Pressure distribution similar

Peak pressure 5 – 6MPa

Average pressure3.35MPa (shoulder belt)

1.53MPa (lap belt)

4.43MPa (shoulder belt)

2.15MPa (lap belt)

Parameters Shoulder belt Lap belt Seat cushion

Peak pressure 6MPa 5MPa 1.5MPa

Concentration upper chest side parts femur bones

Comparison with Numerical Simulation Results

(Provided by Prof. Zhou Q of Tsinghua University)

Location of peak pressure:

upper and lower chest

(shoulder belt)

side parts (lap belt)

Calculated and Measured

values of peak pressure:

5.5MPa vs. 6.0 MPa in

the shoulder belt

3.7MPa vs. 5.0 MPa in

the lap belt

Commercial Applications:

Softceptor™

Softceptor technology imparts

sensations into belts, t-shirts, bras,

footwear, cushions .

We make dumb fabrics smart!

www.advanpro.hk

Sensoria Fitness T-

Shirt

Sensoria Fitness

Sports Bra

Adidas miCoach

Seamless Sports

Bra

Adidas miCoach

Men's Training Shirt

NuMetrex Fabric

Chest Strap

Adidas Bluetooth

Smart Heart Rate

Monitor with Textile

Strap

USD 79 USD 69 USD 54.95 USD 62 USD 29.95 USD 60

Monitoring garments

Socks (1 pair),

anklet & charger

bundle

Socks (4 pairs),

anklet & charger

bundle

Socks

(1pair pack)

Socks

(3 pair pack)

Anklet

USD 129 USD 199 USD 29 USD 59 USD 129

Running socks

Smart shoes

Nike Plus is a tracking system designed to help individuals track fitness performance

The tracking system works with the Fuelband, which displays your energy exertion.

Applications Challenges

• Cost effective and reliable fabrication processes

• Multidisciplinary team with appropriate domain knowledge

• System management and optimization for STWEs

• Commercial company’s roles– product development

– Market exploration

• University’s roles – Postgraduate research program

– Multi-disciplinary research

– Push for new domain knowledge

34

35

Conclusions

Textile-based electronics have been developed in the

Laboratories in universities and companies.

Some of them (sensors and fabric circuit boards)

have reached technology maturity.

The successful industrial adaptation has started to bring up

new industry with combined skills of textiles and

electronics.

Very wide application opportunities for new products &

services in the environment of internet, especially

in the fields of biomedical, healthcare, protective

and security systems.

We need working harder to catch up.

Handbook of Smart Textiles Springer, 2015

▶ Presents a comprehensive overview of smart textiles, from fundamental theory to real applications▶ Supports students and academics through examples & exploration of experimental techniques▶ Provides a working reference tool suitable for those in the smart textiles industry▶ Collates leading expertise from diverse scientific and engineering communities

37

Acknowledgements

Hong Kong Research Grants Council

Hong Kong Research Institute of Textiles and Apparel Ltd

Innovation and Technology Commission

The Hong Kong Polytechnic University

Hong Kong Hospital Authority

Hong Kong Sports Institute

Tsinghua University

Advanpro Ltd

Esquel Enterprises Ltd

High Tech (ShenZhen) Ltd

Intel (HK) Transducers Ltd

Puheng Co Ltd

Shen Zhen Nanhua Electronics Co Ltd

TAL Apparel Ltd

38

Smart Textiles & Apparel Research Team