Dry porous polydimethylsiloxane (PDMS): a novel method using camphor as scaffold

Abstract

An optimal portable microfluidic device should ensure least number of accessories for versatile field application. Typically, in such a device fabricated with polydimethylsiloxane (PDMS), the transport of fluid is enabled through a nonconventional pumping mechanism. This pumping system has been demonstrated to utilize the relatively high air permeability of polydimethyl siloxane (PDMS) to transport small volume fluid. In the recent past, microporous PDMS has replaced PDMS in this capacity. Microporous PDMS is typically fabricated through a series of steps where a sacrificial template is used to infiltrate the polymer. This template is removed after the polymer undergoes curing. This method has consistently produced a spongy structure that is nonrigid, sticky, and moist rendering it unwieldy. In this work, we present a novel concept of using camphor (Cinnamomum camphora) as a template to fabricate a dry polymeric sponge. The proposed sponge is molded on a sublimable material, camphor to avoid the additional step of template dissolution. The sponge is demonstrated to be stiff yet flexible rendering it convenient to be compacted into a confined space. Additionally, the sponge is dry and nonsticky as compared to structures that have been generated through sugar leaching.