Sensing Surfaces Developed from Supercritical Fluid Polymer Processing

摘要

The growing demand for polymer sensing surfaces with specific and improvedrnproperties has catalyzed the development of new methods of polymer synthesis andrnprocessing that provide control at the micro and nanometer scales. As illustrated byrnthe microelectronics industry, the performance potential of these macromolecularrnsurfaces will ultimately be related to the complexity and number of interconnectionsrnthat can be achieved. However, existing techniques for the preparation of polymerrnsurfaces are limited and new coating technologies are required. Rapid Expansion ofrnSupercritical Solutions (RESS) is a spray-on deposition technique that takesrnadvantage of the enormous solubility change that occurs in a rapidly expandingrnsupercritical solution in order to form surfaces consisting of particles with narrow andrntunable size distributions and morphologies. We have been utilizing RESS to depositrnsiloxane-based micro and nanoparticles onto the sensing surface of microfabricatedrnSurface Acoustic Wave (SAW) transducers. We have shown that particle size andrnmorphology can be controlled by adjusting RESS expansion parameters. Thernmechanical properties of developed surfaces are controlled through networkrnformation using room temperature vapor phase crosslinking. The resulting miniaturernchemical sensor was tested upon exposure to organic vapors and exhibits sensitive,rnfast, reversible response.