Stimuli-responsive porous silicon/hydrogel nanocomposites

INOR 485

Ester Segal, essegal@ucsd.edu1, Loren A. Perelman, lperelma@ucsd.edu2, and Michael J. Sailor, msailor@ucsd.edu1. (1) Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, (2) Materials Science and Engineering Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358
A thermoresponsive hydrogel, poly(N-isopropylacrylamide) (polyNIPAM), is synthesized in-situ within thin films of oxidized porous silicon (PSi), leading to composite materials with interesting properties. The Fabry-Perot fringes of the PSi enable direct, real-time observation, by reflectance spectroscopy, of the volume phase transition from a swollen state to a collapsed state (occurring at the lower critical solution temperature, LCST) of the polyNIPAM hydrogel during heating/cooling cycles. A second temperature/pH responsive PSi/hydrogel composite is prepared by copolymerizing NIPAM and acrylic acid (AAc) at different ratios. The polyAAc moieties introduce a pH-sensitive component to the temperature-sensitive component, polyNIPAM. Scanning electron microscopy revealed infiltration of the hydrogels into the nanometer-scale pores of the PSi with excellent adhesion between the hydrogel phase and the PSi surface. The PSi nanostructure provides a unique platform for studying fundamental properties of confined polymer materials. Furthermore, the composites show promise in applications ranging from nano-actuation to drug delivery and biosensing.
 

Nanoscience: Characterization
2:00 PM-5:00 PM, Monday, 11 September 2006 Moscone Center -- Room 309, Oral

Division of Inorganic Chemistry

The 232nd ACS National Meeting, San Francisco, CA, September 10-14, 2006