This research project will develop polymeric chemical sensors that strongly couple selective surface adsorption to mechanical deformation. The ultimate goal is to make devices that amplify the effects of surface adsorption via mechanical instabilities (i.e.,buckling) to facilitate optical and electronic transduction approaches that can be integrated with lab-on-a-chip technology. A specific focus is the implementation of polymers as structural elements in microdevices to exploit their inherent flexibility and biocompatibility. The project has three parallel focus areas: (i) surface functionalization of polymers - surface treatments will be identified which make PDMS chemically-selective for specific target molecules, (ii) microfabrication of freestanding polymeric structures - developing processing techniques to create ultra-compliant structures which experience large deformation upon adsorption, and (iii) optical transduction - creating microchip devices with integrated transduction features. The research is expected to make fundamental advances regarding effective pathways to selective binding with polymeric surfaces, and connections between microfabrication processes and thermomechanical properties (such as modulus and residual stress). The proposed program will directly quantify microdevice performance in terms of surface adsorption, microscale deformation, and thermomechanical properties, using a combination of atomic force microscopy, optical interferometry and nanomechanical testing.
