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Highly Stretchable, Electrically Conductive Textiles Fabricated from Silver Nanowires and Cupro Fabrics Using a Simple Dipping-Drying Method Hui-Wang Cui 1 (), Katsuaki Suganuma 1 , and Hiroshi Uchida 2 Nano Res., Just Accepted Manuscript • DOI: 10.1007/s12274-014-0649-y http://www.thenanoresearch.com on November 24 2014 © Tsinghua University Press 2014 Just Accepted This is a “Just Accepted” manuscript, which has been examined by the peer-review process and has been accepted for publication. A “Just Accepted” manuscript is published online shortly after its acceptance, which is prior to technical editing and formatting and author proofing. Tsinghua University Press (TUP) provides “Just Accepted” as an optional and free service which allows authors to make their results available to the research community as soon as possible after acceptance. After a manuscript has been technically edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP article. Please note that technical editing may introduce minor changes to the manuscript text and/or graphics which may affect the content, and all legal disclaimers that apply to the journal pertain. In no event shall TUP be held responsible for errors or consequences arising from the use of any information contained in these “Just Accepted” manuscripts. To cite this manuscript please use its Digital Object Identifier (DOI®), which is identical for all formats of publication. Address correspondence to Hui-Wang Cui, email: [email protected]. Nano Research DOI 10.1007/s12274-014-0649-y

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Page 1: Highly Stretchable, Electrically Conductive Textiles ... · Highly Stretchable, Electrically Conductive Textiles Fabricated from Silver Nanowires and Cupro Fabrics Using a Simple

Nano Res

1

Highly Stretchable, Electrically Conductive Textiles

Fabricated from Silver Nanowires and Cupro Fabrics

Using a Simple Dipping-Drying Method

Hui-Wang Cui1(), Katsuaki Suganuma1, and Hiroshi Uchida2

Nano Res., Just Accepted Manuscript • DOI: 10.1007/s12274-014-0649-y

http://www.thenanoresearch.com on November 24 2014

© Tsinghua University Press 2014

Just Accepted

This is a “Just Accepted” manuscript, which has been examined by the peer-review process and has been

accepted for publication. A “Just Accepted” manuscript is published online shortly after its acceptance,

which is prior to technical editing and formatting and author proofing. Tsinghua University Press (TUP)

provides “Just Accepted” as an optional and free service which allows authors to make their results available

to the research community as soon as possible after acceptance. After a manuscript has been technically

edited and formatted, it will be removed from the “Just Accepted” Web site and published as an ASAP

article. Please note that technical editing may introduce minor changes to the manuscript text and/or

graphics which may affect the content, and all legal disclaimers that apply to the journal pertain. In no event

shall TUP be held responsible for errors or consequences arising from the use of any information contained

in these “Just Accepted” manuscripts. To cite this manuscript please use its Digital Object Identifier (DOI®),

which is identical for all formats of publication.

Address correspondence to Hui-Wang Cui, email: [email protected].

Nano Research

DOI 10.1007/s12274-014-0649-y

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Nano Res

2

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TABLE OF CONTENTS (TOC)

Highly Stretchable, Electrically Conductive Textiles

Fabricated from Silver Nanowires and Cupro

Fabrics Using a Simple Dipping-Drying Method

Hui-Wang Cui1,*, Katsuaki Suganuma1, and Hiroshi

Uchida2

1 Institute of Scientific and Industrial Research, Osaka

University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047,

Japan.

2 Institute for Polymers and Chemicals Business

Development Center, Showa Denko K. K., 5-1 Yawata

Kaigan Dori, Ichihara, Chiba 290-0067, Japan.

Page Numbers. The font is

ArialMT 16 (automatically

inserted by the publisher)

Highly stretchable, electrically conductive textiles were fabricated

from silver nanowires and cupro fabrics using a simple

dipping-drying method, that they had displayed low electrical

resistances at 0.0047-0.0091 Ω in the range of 0%-190% strains.

Provide the authors’ website if possible.

Author 1, website 1

Author 2, website 2

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Highly Stretchable, Electrically Conductive Textiles Fabricated from Silver Nanowires and Cupro Fabrics Using a Simple Dipping-Drying Method

Hui-Wang Cui1(), Katsuaki Suganuma1, and Hiroshi Uchida2

1 Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan. 2 Institute for Polymers and Chemicals Business Development Center, Showa Denko K. K., 5-1 Yawata Kaigan Dori, Ichihara, Chiba

290-0067, Japan.

Received: day month year / Revised: day month year / Accepted: day month year (automatically inserted by the publisher)

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2011

ABSTRACT In this study, we combined silver nanowires and cupro fabrics together using a dipping-drying method to

prepare electrically conductive textiles. The silver nanowires were adhered and absorbed onto microfibers to

form electrically conductive fibers, and also filled into the gaps and spaces between/among microfibers, and

stacked, piled together to form the electrically conductive networks, which both had given highly electrical

conductivity to the electrically conductive textiles. The obtained electrically conductive textiles presented low

resistance and good stretchability, e.g., 0.0047-0.0091 Ω in the range of 0%-190% strains. The obtained

electrically conductive textiles also presented excellent flexibility, whether stretched, shrunk, or bent, they still

kept highly, stably electrical conductivity, which can be used as smart textiles, especially in those fields

associated with weave, electronics, biology, medicine, food, life, clothes, aviation, and military.

KEYWORDS A. Fabrics/textiles; A. Metals; A. Smart materials; B. Electrical properties.

Address correspondence to Hui-Wang Cui, email: [email protected].

Nano Res DOI (automatically inserted by the publisher)

Research Article

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1. Introduction

Smart textiles, a class of highly intelligent

textiles integrated by the multi-disciplinary

knowledge (e.g., textile, electronics, chemistry,

physics, mechanics, biology, medicine, etc.), is based

on the concept of biomimicry, capable of simulating

life system, and has the dual function that can

effectively perceive and response to various changes

and stimuli from the environment, such as

mechanics, heat, light, temperature, electromagnetics,

chemicals, biological odors, and so on. Till now, a

variety of functional smart textiles, e.g., thermostat

textiles, physiological state telemetry textiles, solar

textiles, shape memory textiles, waterproof and

moisture permeable textiles, color-changing textiles,

and E-smart textiles, have been greatly developed.

Among them, the E-smart textiles are a kind of novel

textiles, which is based on electronics, integrating

some hi-tech solutions such as sensing,

telecommunication and artificial intelligence into

textiles. While the E-smart textile applications have

made a limited commercial impact so far, with

relatively small volumes of commercial products

launched primarily in the high performance apparel

sector, predictions for growth of this market as a

whole are huge. As deep integration of several

cutting-edge technologies such as micro-electronics,

nanotechnology, and biotechnology, E-smart textiles

are one of the most dynamic and fast growing

sectors and offers huge potential [1-2].

How to prepare electrically conductive textiles

(also called electrically conductive fibers) is the key

to produce E-smart textiles. Coating [3], depositing

[4], spinning [5], printing [6], synthesizing [7],

dipping [8], and solution growing [9] methods have

been used widely to fabricate electrically conductive

textiles from the conductive polymers (e.g.,

polypyrrole [10], polyaniline [11], the mixture of

poly(3,4-ethylenedioxythiophene) and

poly(4-styrenesulfonate) [12]), metal particles (e.g.,

silver [13], copper [14], nickel [15], aluminum [16],

zinc [17]), and carbon fillers (e.g., graphite

nanoplatelets [18], carbon nanotube [19]). About the

silver based smart textiles, silver particles are often

used. For example, Xue et al produced silver

nanoparticles on cotton fibers by reduction of

[Ag(NH3)2]+ complex with glucose, and the silver

nanoparticles formed dense coating around the

fibers rendering the intrinsic insulating cotton

textiles conductive [20]. Paul et al printed a

polyurethane paste on to a woven textile to create a

smooth, high surface energy interface layer, and

subsequently printed a silver paste on top of this

interface layer to provide a conductive track, which

was then encapsulated with another layer of

polyurethane paste so that the silver track was

protected from abrasion and creasing, forming the

electrodes [21, 22]. Apparently, the usage of silver

nanowires (AgNWs), which are with large aspect

ratio and can present higher flexibility than silver

particles [23-25], to fabricate smart textiles have been

seldom reported. Therefore, in this study, we

combined the AgNWs and cupro fabrics together

using a dipping-drying method to prepare

electrically conductive textiles [Figure 1(a)]. The

AgNWs were adhered and absorbed onto

microfibers to form electrically conductive fibers,

and also filled into the gaps and spaces

between/among microfibers, and stacked, piled

together to form the electrically conductive networks,

which both had given highly electrical conductivity

to the electrically conductive textiles.

2. Experimental

2.1. Samples

AgNWs were synthesized in a large scale

according to the previously reported polyol

procedures [26, 27]. They were ≥60 μm, even 100

μm in length, the diameter was about 60 nm, and

dispersed in ethanol to form a 0.5% suspension

solution [Figure 1(a)]. The textile (100 mm×100 mm

× 250 μm) was a cellulosic product, named

BEMCOTTM M-3 cupro fabric (Asahi Kasei Fibers

Corporation, Tokyo, Japan) [Figure 1(a)]. The

fabrication process of the electrically conductive

textiles is illustrated in Figure 1(a). The pure textiles

were dipped into the AgNWs suspension solution

for about 2 h, and then they were dried at room

temperature to completely volatilize the ethanol.

Finally the electrically conductive textiles were

obtained.

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Figure 1 (a) Fabrication process of electrically conductive

textiles; the inserted SEM images show the grid-like structures of

pure textiles and electrically conductive textiles. (b) Sample of

electrically conductive textiles at 50 mm×10 mm×250 μm. (c)

SEM images of the electrically conductive fibers and the

electrically conductive networks formed between fibers; the

inserted SEM images show the partial amplifications of the

electrically conductive fibers and electrically conductive

networks. (d) Stretch, break, and stress areas of the electrically

conductive textiles at 210% strain, and the force directions in

them; the SEM images show the disorderly bundle structures, the

electrically conductive fibers, and the torn electrically conductive

networks.

2.2. Characterization

Wide-angle X-ray diffraction (WAXRD) data

were collected on a Rigaku RINT RAPID curved

imaging plate area detector (Rigaku Corporation,

Tokyo, Japan) using Mo Kα (λ=1.54 Å ) at 40 kV, 30

mA for 10 min. The thermal degradations of the

samples were measured using a NETZSCH

2000SE/H/24/1 thermogravimetric analyzer (TGA,

NETZSCH, Selb, Germany) operated under a pure

N2 atmosphere. The sample (ca. 10 mg) was placed in

a Pt cell and heated at a rate of 10 °C·min-1 from 30 to

900 °C under a N2 flow rate of 60 ml·min-1. Scanning

electron microscopic (SEM) images of the samples

were recorded using a Hitachi SU8020 field emission

scanning electron microscopy (FE-SEM) microscope

(Hitachi, Tokyo, Japan) operated at an accelerating

voltage of 5 kV and an accelerating current of 2 μA.

Figure S1 shows the test method of electrical

resistance during tensile stretching. The samples (50

mm×10 mm×250 μm) [Figures 1(b) and S1] were

uniaxially stretched up to 210% strain at a rate of 1

mm·min-1 using an EZ test compact table-top

universal tester (Shimadzu, Kyoto, Japan). The

distance between two chucks was 30 mm at the

beginning. The electrical resistance of the samples

during tensile stretching was measured using an

Agilent Technologies 34410A multimeter and an

Agilent Technologies 11059A Kelvin probe set

(Agilent Technologies, Santa Clara, California, USA)

through a four-point probe method.

3. Results and discussion

As Figure 1(a) shows, the white pure textile,

before dipped into the AgNWs suspension solution,

had loose grid-like structures, the grid frameworks

were consisted of hundreds of microfibers, which

were physically knitted together [the inserted SEM

image in Figure 1(a)]. After dipped into the AgNWs

suspension solution, the textiles were electrically

conductive textiles and the color became into silver

gray. Compared to the pure textiles, the electrically

conductive textiles featured diffraction angles (2θ) at

37.98, 43.94, 64.07, 77.61, and 81.58 o on the WAXRD

patterns, corresponding to the characteristic

diffraction peaks of (111), (200), (220), (311), and (222)

for AgNWs, respectively [Figure 2(a)]. The char yield

of pure textiles was 7% up to 900 oC, while that of

electrically conductive textiles was 40%, and

therefore, the electrically conductive textiles

contained about 30% AgNWs in them [Figure 2(b)].

The electrically conductive textiles had more

apparent grid-like structures than the pure textiles. It

seemed that the AgNWs played a role of bonding

those hundreds of microfibers densely to form the

solid grid frameworks [Figure 1(a) and the inserted

SEM image]. AgNWs were absorbed and adhered

onto the microfibers by physical effects, that they

two formed the electrically conductive fibers [Figure

1(c) and the inserted SEM image].

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20 40 60 80 100 200 400 600 800

0

20

40

60

80

100

(222)

(311)(220)

(200)

Inte

nsi

fy (

au)

2 (o)

(111)

Pure Textiles

(b)

Wei

ght

Per

centa

ge

(%)

Temperature (oC)

(a)

Electrically Conductive

Textiles

Figure 2 (a) WAXRD patterns and (b) TGA traces of pure

textiles and electrically conductive textiles.

Additionally, the AgNWs also filled into the gaps

and spaces between/among these microfibers, and

stacked, piled together, formed the electrically

conductive networks [Figure 1(c) and the inserted

SEM image]. Precisely due to these electrically

conductive fibers and networks, they guaranteed the

highly electrical conductivity for the electrically

conductive textiles.

The electrical resistance closely relates to the

electrically conductive channels, the more the latter

the lower the former [28, 29]. In the electrically

conductive textiles, the electrically conductive fibers

and networks constituted the electrically conductive

channels. As Figure 1(c) shows, the AgNWs adhered

onto the microfibers forming the electrically

conductive fibers, and filled into the gaps and spaces

between/among these microfibers, stacked and piled

together, forming the electrically conductive

networks. These two structures increased the

electrically conductive channels that had provided

low electrical resistances to the electrically

conductive textiles.

Figure 3 shows the electrical resistances of

electrically conductive textiles changing with the

stretching strains. The electrical resistance increased

very slow, even nearly kept at a constant value in the

range of 0%-190% strains, sharply increased from

200% strain to 210% strain. At 0% strain, meaning

unstretched, the electrical resistance was 0.0047 Ω,

Figure 3 Electrical resistances of the electrically conductive

textiles vs strains; the inserts are the digital images of LED

integrated circuit with electrically conductive textiles at (a) 0%

strain, (b) 150% strain, and (c, d) as electronic skins

then it increased slowly like snail crawling with the

increasing strains, reached to 0.0067 Ω at 180% strain

and 0.0091 Ω at 190% strain. The electrical resistance

changed so small that it could be considered almost a

constant value in the range of 0%-190% strains. The

electrical resistance increased to a larger value of

0.0274 Ω at 200% strain and to the largest value of

112.1649 Ω at 210% strain in all the tests of this study.

The electrically conductive textiles had

presented low electrical resistance. And the electrical

resistance changed slightly in the range of 0%-190%

strains and dramatically in the range of 200%-210%

strains, which had a close relationship to the changes

of the grid-like structures during the stretching.

Loading the uniaxial force, the electrically

conductive textiles were stretched gradually at a rate

of 1 mm·min-1. They displayed two different

stretching states, called stretch areas and stress areas

in the range of 0%-190% strains, and three different

stretching states, called stretch areas, break areas,

and stress areas in the range of 200%-210% strains

[Figures 1(d) and 4]. Under stretching, the loaded

uniaxial force acted on the microfibers; the force was

parallel in the stretch areas, as shown in Figure 1(d),

and only the loaded force caused the rupture of

grid-like structures in these areas.

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Figure 4 Microstructures of (a) stretched samples, (b) stretch

areas, and (c) stress areas of electrically conductive textiles at

0%, 50%, 100%, 150%, 200%, and 210% strains. (d)

Microstructures of break areas of electrically conductive textiles

at 200% and 210% strains.

As Figure 4(b) shows, the electrically conductive

textiles did not have any ruptures at 0%, 50%, 100%,

and 150% strains, still kept clear grid-like structures,

and the grids became large accordingly with the

increasing strain. While the grid-like structures

seemed vague, and showed slight ruptures at 200%

and 210% strains, only a few grids were found. SEM

further confirmed this. Apparently, the grids of

electrically conductive textiles were the largest at

100% strain [Figure 5(c)], then those at 50% strain

[Figure 5(b)] and 0% strain [Figure 5(a)] followed,

caused by the stretching; the grid frameworks were

still dense and solid at 0% and 50% strains [Figures

5(a) and 5(b)], but loose at 100% strain [Figure 5(c)].

Only several grids were observed at 150% strain

[Figure 5(d)], no grids were found out at 200% and

210% strains [Figures 5(e) and 5(f)], and their

frameworks all were destroyed, became into

irregular bundles.

Figure 5 SEM images of stretch areas of electrically conductive

textiles at (a) 0%, (b) 50%, (c) 100%, (d) 150%, (e) 200%, and (f)

210% strains; SEM images of stress areas of electrically

conductive textiles at (g) 0%, (h) 50%, (i) 100%, (j) 150%, (k)

200%, and (l) 210% strains.

In the stress areas, because two chucks

sandwiched the sample (Figure S1), they influenced

the stretching state significantly and produced

stresses to accelerate the rupture of samples. As

Figure 4(c) shows, the electrically conductive textiles

did not display any ruptures at 0% and 50% strains,

the grids also got large. The electrically conductive

textiles displayed slight ruptures at 100% strain, and

significant ruptures at 150%, 200%, and 210% strains;

their grid-like structures were destroyed completely,

and became into bundles of microfibers. Under SEM

observation, the electrically conductive textiles had

small grids at 0% strain while large grids at 50%

strain, and the grid frameworks at 50% strain were

looser than those at 0% strain; they all still had the

clear grid-like structures [Figures 5(g) and 5(h)].

Only several grids were observed in the electrically

conductive textiles at 100% strain, and no one was

found at 150%, 200%, and 210% strains; their grid

frameworks were completely destroyed, they

changed from grid-like structures into bundles of

disorder microfibers [Figures 5(i), 5(j), 5(k), and 5(l)].

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Obviously, the changes of grid-like structures in

stretch areas of electrically conductive textiles were

somewhat different from those in stress areas, but all

grids became large from small with the increasing

strain until they were destroyed completely, all grid

frameworks changed from solid, dense to loose, and

became fully ruptured eventually, and all the regular

grid-like structures changed into disorder bundles of

microfibers [Figures 4 and 5].

As mentioned above and stated in Figures 4 and

5, the stretch and stress areas of electrically

conductive textiles changed corresponding with the

increasing strain, even were totally ruptured, but

AgNWs still adhered onto those microfibers, the

electrically conductive fibers still existed, not broken.

Figure 6 shows the microstructures of these

electrically conductive fibers. AgNWs were absorbed

and adhered onto the microfibers that they two

formed the electrically conductive fibers, even like

electrically conductive rods. The stretching did not

influence them, that the electrically conductive fibers

at 0% [Figure 6(a1) and 6(a2)], 50% [Figures 6(b1)

and 6(b2)], 100% [Figures 6(c1) and 6(c2)], 150%

[Figures 6(d1) and 6(d2)], 200% [Figures 6(e1) and

6(e2)], and 210% [Figures 6(f1) and 6(f2)] strains all

were the same. AgNWs covered and packed the

microfibers densely, forming the electrically

conductive channels and having conducted the

electricity effectively. At high amplification, the

adhering states or arrangements of AgNWs on the

microfibers were available. As shown in Figures 6(a3)

-6(f3), AgNWs stacked, piled densely, like noodles

gathered together. It also can be seen that the

stretching did not affect anything of them that the

AgNWs still gathered, stacked together disorderly as

their original states in electrically conductive textiles.

And from 0% to 210% strain, the adhering states or

arrangements of AgNWs on the microfibers were the

same, all displayed irregularity and disorder.

The electrically conductive channels resulted

from two sources: the electrically conductive fibers

formed by the microfibers and the adhered AgNWs

on them and the electrically conductive networks

formed by AgNWs in the gaps and spaces

between/among microfibers [Figure 1(c)].

Figure 6 SEM images of electrically conductive fibers at (a1, a2,

a3) 0%, (b1, b2, b3) 50%, (c1, c2, c3) 100%, (d1, d2, d3) 150%,

(e1, e2, e3) 200%, and (f1, f2, f3) 210% strains at ×400 k, ×

2.00 k, and ×10.0 k (from left to right).

During or after the stretching, the microstructures of

electrically conductive fibers were not changed, and

the electrically conductive channels from them were

not destroyed, as shown in Figure 6. However, the

electrically conductive networks were destroyed at

an extent by the stretching. As Figure 7(a) shows, at

0% strain that not stretched, the AgNWs developed

large, dense, and solid electrically conductive

networks between/among microfibers. These

AgNWs stacked, piled, and arranged disorderly, as

shown in the inserted SEM image in Figure 7(a).

Loaded by the uniaxial force, the electrically

conductive textiles were stretched and the

electrically conductive networks were gradually

cracked. With the increasing strain from 0% to 210%,

the electrically conductive networks were destroyed,

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changing from large, continues size to small flake

size [Figures 7(b), 7(c), 7(d), 7(e), and 7(f)]. The

electrically conductive networks were parted from

their adhered microfibers, so they did not combine

with the electrically conductive fibers so closely as

that at 0% strain. Despite this, the electrically

conductive networks still had enough electrically

conductive channels that resulted from the contacts

between/among these flakes, as well as the

electrically conductive channels that resulted from

the contacts between/among electrically conductive

networks and electrically conductive fibers, which

both had given low electrical resistance to the

electrically conductive textiles. Therefore, as shown

in Figure 3, the electrical resistance of electrically

conductive textiles increased from 0.0047 Ω to 0.0091

Ω with the increasing strain from 0% to 190% strain;

the increase was rather small.

Besides the stretch and stress areas, the

electrically conductive textiles also had the break

areas at 200% and 210% strain caused by the broken

of microfibers. Similar to the stretch areas, only the

loaded uniaxial force acted on the microfibers, the

force was parallel in the break areas [Figure 1(d)]. As

Figure 4(d) shows, only limited electrically

conductive fibers existed in the break areas, and they

were all torn, almost disconnected. Under the SEM

observation, the electrically conductive fibers were

only a few and scattered [Figures 8(a1) and 8(b1)],

greatly different from those in the stretch and stress

areas shown in Figure 5.

Figure 7 SEM images of electrically conductive networks at (a)

0%, (b) 50%, (c) 100%, (d) 150%, (e) 200%, and (f) 210%

strains; the insert in (a) is the partial amplification of the

electrically conductive networks.

Figure 8 SEM images of (a1) break areas of electrically

conductive textiles at 200% strain, and (a2) the torn electrically

conductive networks, the electrically conductive fibers at (a3)

×400 k, (a4) ×2.00 k, and (a5) ×10.0 k; SEM images of (b1)

break areas of electrically conductive textiles at 210% strain,

and (b2) the torn electrically conductive networks, the

electrically conductive fibers at (b3) ×400 k, (b4) ×2.00 k,

and (b5) ×10.0 k.

Additionally, the electrically conductive networks

were almost completely destroyed, only a few small

flakes left, the electrically conductive channels

resulted from them were nearly broken [Figures

8(a2) and 8(b2)]. Although most electrically

conductive fibers broke, disconnected in the break

areas, the left still showed highly electrical

conductivity. The microstructures were not

destroyed totally, AgNWs still adhered onto the

microfibers, and stacked, piled on them, and

arranged disorderly at 200% and 210% strains

[Figures 8(a3)-8(a5) and 8(b3)-8(b5)], same to

those in Figure 6. Because the electrically

conductive networks were almost completely

broken and the most electrically conductive fibers

were disconnected, the electrically conductive

channels resulted from them were reduced

correspondingly, and the electrical resistance

increased significantly, such as 0.0274 Ω at 200%

strain and 112.1649 Ω at 210%, much higher than

those values in the range of 0%-190% strains

[Figure 3].

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As aforementioned, AgNWs were absorbed and

adhered onto the microfibers by physical effects, that

they two formed the electrically conductive fibers

[Figure 1(c) and the inserted SEM image]; and the

additional AgNWs filled into the gaps and spaces

between/among these microfibers, and stacked, piled

together, formed the electrically conductive networks

[Figure 1(c) and the inserted SEM image]. The

absorbance and adherence were reflected by the

electrically resistant durability of the obtained

electrically conductive textiles against water washing.

As shown in Figure 9, the electrically conductive

textiles (100 mm×10 mm×250 μm) were dipped into

25 oC water stirred by a SANYO SAS-700 Magnetic

Stirrer (SANYO, Tokyo, Japan) at 500 rpm, the

electrical resistance kept stably in the range of 0.0035

-0.0048 Ω, which was almost the same to that 0.0047

Ω for the unstretched electrically conductive textiles

in Figure 3. From this, it can be seen that the

electrically conductive textiles displayed high

durability, and the AgNWs were well absorbed and

adhered onto the microfibers that could not be

removed or scratched easily. The highly, stably

electrical conductivity of these electrically

conductive textiles were also indicated by the digital

images of LED integrated circuit with them, as the

un-stretched and stretched electrically conductive

textiles had presented at 0% strain [Figure 3(a)] and

150% strain [Figure 3(b)], respectively. Moreover, the

electrically conductive textiles were further adhered

onto fingers, like electronic skins, whether stretching,

shrinking, or bending the joints, they also showed

highly, stably electrical conductivity, as shown in

Figures 3(c) and 3(d).

Comparing to those already reported methods

of fabricating electrically conductive textiles, the

methods reported in this study had displayed

several advantages. Firstly, the dipping-drying

method used in this study was much simpler than

the coating [3], depositing [4], spinning [5], printing

[6], synthesizing [7], solution growing [9], and the

reported methods of silver based smart textiles

[20-22], albeit it was similar to that of the “dyeing”

textiles from single-walled carbon nanotubes and

cotton fibers [30].

Figure 9 Electrically resistant durability of electrically

conductive textiles in 25 oC@500 rpm stirring water; the insert

is the stirred state of electrically conductive textiles in water.

Secondly, the AgNWs used in this study were

industrially fabricated in a large scale using the

polyol procedures, which had more output than that

of graphite nanoplatelets [18] and carbon nanotube

[19, 30]; the diameter was about 60 nm and the

length was more than 60 μm for the AgNWs used in

this study, the aspect ratio was more than 1000, much

larger than those of graphite nanoplatelets, carbon

nanotube, and silver particles used by Nilsson et al.

[18], Khumpuang et al. [19], Xue et al. [20], Paul et al.

[21, 22], and Hu et al. [30], which had ensured the

high conductivity of electrically conductive textiles

fabricated in this study. Thirdly, the electrically

conductive textiles fabricated in this study had

presented super low electrical resistance of 0.0047 Ω

before stretched, while those electrically conductive

textiles fabricated from graphite nanoplatelets,

carbon nanotube, and silver particles presented the

electrical conductivity at 0.22 S·cm-1 [18], the

electrical resistance at 200-400 Ω [19] and 10-20 Ω

[19], and the sheet resistance at 3 Ω·sq-1 [30]. Fourthly,

the electrically conductive textiles fabricated in this

study had presented highly electrical-stretchable

stability, the electrical resistance was 0.0047 Ω at 0%

strain, 0.0067 Ω at 180% strain, 0.0091 Ω at 190%

strain, and 0.0274 Ω at 200% strain, indicating that

the electrical resistance could be considered constant

in the range of 0%-190% strains, which was similar,

even superior to the stable specific capacity at 62 F·g-1

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10

for the stretchable conductor with porous textile

conductors as electrodes and current collectors

before and after stretching to 120% strain [30]. Fifthly,

the electrically conductive textiles fabricated in this

study had presented highly electrically resistant

durability, the electrical resistance kept stably in the

range of 0.0035-0.0048 Ω under dipped into the 25 oC@500 rpm stirring water, which was almost the

same to that 0.0047 Ω for the unstretched electrically

conductive textiles, showing their excellent

resistance to water washing; this was similar, even

superior to the unchanged sheet resistance at 3 Ω·sq-1

for the single-walled carbon nanotubes and cotton

fibers before and after water washing [30]. Sixthly,

the cupro fabric used in this study came from natural

cellulose, rather than chemical fibers from

conductive polymers [10-12], which could give good

biological properties and biocompatibility to the

electrically conductive textiles. Finally, the AgNWs

were industrially fabricated in a large scale and the

cupro fabric came from natural cellulose, from which

the electrically conductive textiles fabricated in this

study definitely would have a lower cost than those

from conductive polymers [10-12], graphite

nanoplatelets [18], and carbon nanotube [19, 30].

Moreover, to further reduce the cost, the methods

resulting in a high coverage ratio on microfiber with

as less as possible usage of AgNWs, e.g., adjusting

the concentration of AgNWs suspension solution,

changing the dipping time of textiles into AgNWs

suspension solution, and letting Ag ions grow into

nanowires along the seeds of microfibers, will be

conducted in the future to make better results for the

electrically conductive textiles. In a word, the

electrically conductive textiles have shown low

electrical resistance and excellent flexibility, can be

used as smart textiles, especially in those fields

associated with weave, electronics, biology, medicine,

food, life, clothes, aviation, and military.

4. Conclusions

In this study, we combined AgNWs and cupro

fabrics together using a dipping-drying method to

prepare electrically conductive textiles. The AgNWs

were adhered and absorbed onto microfibers to form

electrically conductive fibers, and also filled into the

gaps and spaces between/among microfibers, and

stacked, piled together to form the electrically

conductive networks, which both had given highly

electrical conductivity to the electrically conductive

textiles. The obtained electrically conductive textiles

presented low resistance and good stretchability, e.g.,

0.0047 Ω at 0% strain, 0.0067 Ω at 180% strain, and

0.0091 Ω at 190% strain. Moreover, the obtained

electrically conductive textiles also presented

excellent flexibility, whether stretched, shrunk, or

bent, they still kept highly, stably electrical

conductivity, which can be used as smart textiles,

especially in those fields associated with weave,

electronics, biology, medicine, food, life, clothes,

aviation, and military.

Electronic Supplementary Material: Supplementary

material (Test method of electrical resistance during

tensile stretching) is available in the online version of

this article at

http://dx.doi.org/10.1007/s12274-***-****-*

(automatically inserted by the publisher).

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Electronic Supplementary Material

Highly Stretchable, Electrically Conductive Textiles Fabricated from Silver Nanowires and Cupro Fabrics Using a Simple Dipping-Drying Method

Hui-Wang Cui1(), Katsuaki Suganuma1, and Hiroshi Uchida2

1 Institute of Scientific and Industrial Research, Osaka University, Mihogaoka 8-1, Ibaraki, Osaka 567-0047, Japan. 2 Institute for Polymers and Chemicals Business Development Center, Showa Denko K. K., 5-1 Yawata Kaigan Dori, Ichihara, Chiba

290-0067, Japan.

Received: day month year / Revised: day month year / Accepted: day month year (automatically inserted by the publisher)

© Tsinghua University Press and Springer-Verlag Berlin Heidelberg 2011

INFORMATION ABOUT ELECTRONIC SUPPLEMENTARY MATERIAL.

Figure S1 Test method of electrical resistance during tensile stretching

Address correspondence to Hui-Wang Cui, email: [email protected].