Development of a Flex and Stretchy Conductive Cotton Fabric Via Flat Screen Printing of PEDOT:PSS/PDMS Conductive Polymer Composite

Abstract

In this work, we have successfully produced a conductive and stretchable knitted cotton fabric by screen printing of poly(3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) and poly(dimethylsiloxane-b-ethylene oxide)(PDMS-b-PEO) conductive polymer composite. It was observed that the mechanical and electrical properties highly depend on the proportion of the polymers, which opens a new window to produce PEDOT:PSS-based conductive fabric with distinctive properties for different application areas. The bending length analysis proved that the flexural rigidity was lower with higher PDMS-b-PEO to PEDOT:PSS ratio while tensile strength was increased. The SEM test showed that the smoothness of the fabric was better when PDMS-b-PEO is added compared to PEDOT:PSS alone. Fabrics with electrical resistance from 24.8 to 90.8 kΩ/sq have been obtained by varying the PDMS-b-PEO to PEDOT:PSS ratio. Moreover, the resistance increased with extension and washing. However, the change in surface resistance drops linearly at higher PDMS-b-PEO to PEDOT:PSS ratio. The conductive fabrics were used to construct textile-based strain, moisture and biopotential sensors depending upon their respective surface resistance.

Keywords: PEDOT:PSS; conductive polymer composite; flexible electronics; wearable application.

Figure 1

Chemical structure: (a) polystyrene sulfonate (PEDOT:PSS); (b) poly(dimethylsiloxane-b-ethylene oxide) (PDMS-b-PEO).

Figure 2

Effect of WR treatment on knitted cotton fabric: (a) PEDOT:PSS polymer dispersion on untreated fabric (S0); (b) drops of water on untreated fabric (S0); (c) drops of water on water repellent (WR)-treated fabric (S1); (d) PEDOT:PSS polymer dispersion on water repellent (WR)-treated fabric.

Figure 3

Screen printing of conductive polymer composite on knitted cotton fabric.

Figure 4

(a) Schematic design of the conductive textile fabric; (b) actual conductive textile fabric.

Figure 5

Two-point method resistance measurements set-up.

Figure 6

(a) Arduino Nano electronic circuitry design; (b) resistance measurements set-up.

Figure 7

Effect of PEDOT:PSS/PDMS-bb-PEO on thickness.

Figure 8

Load-elongation curve.

Figure 9

SEM: (a) WR treated; (b) PEDOT:PSS coated; (c) PEDOT:PSS-PDMS:PEO coated.

Figure 10

Effect of PDMS-b-PEO concentration on resistance: (a) effect of PEDOT:PSS to PDMS-b-PEO ratio on resistance at different surface area, width kept constant; (b) effect of PDMS-b-PEO on surface resistance.

Figure 11

PEDOT:PSS/PDMS-b-PEO coated cotton electrodes for: (a) strain dynamic response at 0.67 cm/s rate of stretching for six seconds; (b) moisture dynamic response at1 ml/s rate of water spray for six seconds; (c) electrocardiography (ECG) signal using PC-80B; (d) electroencephalography (EEG) signal using OpenBCI board.

Figure 11

PEDOT:PSS/PDMS-b-PEO coated cotton electrodes for: (a) strain dynamic response at 0.67 cm/s rate of stretching for six seconds; (b) moisture dynamic response at1 ml/s rate of water spray for six seconds; (c) electrocardiography (ECG) signal using PC-80B; (d) electroencephalography (EEG) signal using OpenBCI board.

Figure 12

Effect of stretching on surface resistance and sensing stability: (a) Change in resistance due to stretching; (b) surface resistance at different stretching cycles.

Figure 13

Effect of washing on the surface resistance at different PDMS-b-PEO to PEDOT:PSS ratios: (a) surface resistance before and after washing; (b) percentage change in surface resistance due to washing.