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Abstract
Stretchable conductors have been developed in the past decade with new technological advancement. Highly stretchable conductive materials provide unique advantages in flexible electronics as well as in many advanced fields. In this study, it would be divided into two parts. In the first part, we created elastic porous polydimethylsiloxane (p-PDMS) as high stretchable conductive substrate. The p-PDMS surface was fabricated by simple soft lithography process that replicates the 3D corrugated porous microstructures from a low-cost conventional available abrasive paper. Conductive polypyrrole (PPy) was polymerized on the p-PDMS surface by UV/Ozone (UVO) surface treatment to create the high stretchable conductive PPy/p-PDMS film. The PPy/p-PDMS film shows high stretchability maximum upto 80% strain. Effect of PPy/p-PDMS electrical properties to the critical PPy/p-PDMS process parameters such as UVO treatment time, deposition time, and abrasive paper grit size were evaluated in this paper in great detail. Results indicate that highest electrical conductivity of 34.9 S/m was found in the optimized PPy/p-PDMS process condition. And high number of cyclical bending and stretching of PPy/p-PDMS film upto 1,000 cycles were also reported as good PPy/p-PDMS repeatability with maximum 5% (bending) and 36% (20% stain stretching) resistance increment after 1,000 repeating cycles. In the second part, we propose a new fabrication method to create highly stretchable, conductive p-PDMS microchannel base on PPy/p-PDMS process. The p-PDMS microchannel was fabricated by standard soft-lithography process from an abrasive paper imprinted SU-8 micromold. Oxygen plasma treatment was applied to bond the microchannel and the PPy layer was coated into the microchannel to fabricate a stretchable conductive PPy/p-PDMS microfluidic device. The PPy/p-PDMS microchannel showed both good electrical property and stretchability. The electrical properties of different layouts, including straight, curved, angled, and complex serpentine PPy/p-PDMS microchannel under stretching were investigated. Mouse embryonic fibroblasts, NIH/3T3, were also cultured inside the microchannel to demonstrate biocompatibility of PPy/p-PDMS microchannels. Finally, 1,000 times cyclic stretching and bending tests were performed to evaluate the reliability of PPy/p-PDMS microchannel. | en_US |