Fabrication of a Gold Nanostar - Embedded Porous Poly(dimethylsiloxan) Platform for Sensing Applications

Porous poly(dimethylsiloxan) (PDMS) membranes have been fabricated by using sodium bicarbonate powder and polystyrene microspheres to generate the pores. Large gold nanostars (AuNSs) have been synthesized by a one-pot surfactant-free method by using gold seeds, and the stars have been embedded into the porous material by immersing the samples in the nanostars’ (NSs) aqueous solution. Sensitivity tests performed with samples prepared with the two porogens demonstrated the very high sensitivity toward the surrounding environment of gold nanostars embedded into the polymer. The sensitivity is found to be in the range of 400-550 nm/RIU, compared to approximately only 100 nm/ refractive index unit (RIU) for PDMS with embedded nanospheres. Absorbance spectra of nanostars embedded in the polymer are simulated by using the Finite Difference Time Domain (FDTD) method. A good agreement is found between the calculated and experimental spectra