Self-assembled synthesis and characterization of microchannels in polymeric membranes

This article describes a novel self-assembly approach to create microchannels in polydimethylsiloxane (PDMS) membranes using poly(ethylene oxide) (PEO) and polyurethane (PU). The interactions between hydrophilic PEO/PU and hydrophobic PDMS, as it cross-links, result into PEO/PU pushed out of the bulk PDMS. As this occurs, PEO/PU particles leave behind their tracks. PEO depicts ease of handling, better inherent alignment, and excellent repeatability. Fourier transform infrared spectroscopy, optical/confocal laser scanning microscopy, and fluid flow measurements are done to characterize the microfluidic channels. These channels have a circular cross-section and are parallel to each other. PEO generates smaller channels compared to PU. The diameter, arrangement, and height of these channels are seen to depend on temperature; for example, channel length increases linearly with temperature. An interdependent relationship between temperature, pore size, and number of pores is also exhibited. During phase separa...