Towards smart "lining" for microfluidic channels with stimulus responsive polymers

In this Thesis, the development and the characterization of polymeric films with the ultimate goal of switching the properties of functionalized microchannel surfaces is presented. The coatings were mainly based on two types of stimulus responsive polymers, temperature responsive poly(N-isopropylacrylamide)(PNIPAM) and redox-responsive poly(ferrocenylsilane) (PFS). These polymers allow one to control wettability, adhesion force, and friction which are important variables for preparing designer microchannels. Surface switching was primarily studied by colloid probe AFM. The motivation for the choice of PNIPAM and PFS is rationalized by their responsiveness and by the opportunities for anchoring these polymers to solid substrates, allowing one to functionalize the inner walls of microfluidic devices and tune the surface properties of these walls to control flow. As a proof of concept, we present a study of PFS functionalized channels for switchable delay valves.