thermal manipulation of gold nanocomposites for microfluidic platform optimization

Surface gold–polymer nanocomposites are prepared by using the thermal convection method for the deposition of gold colloids onto the surface of four polymer films: poly(-vinyl alcohol) (pva), su-82, poly(styrene) (ps), and poly(dimethyl siloxane) (pdms). in order to increase the plasmonic sensitivity of the platforms, the nanocomposites are, subsequently, subjected to an incremental heating in the range of 80–200 °c. as a consequence, small aggregates are formed and uniformly dispersed on the surface of the film. in addition, because of the softening of the polymer, a small fraction of nanoparticles “sinks” into the surface layer. because of the different thermal properties of the polymers and the interac-tions between the nanoparticles and the polymer chains, the final configuration of the thermally “manipulated” nanocom-posites will not be the same. it is found that, among the poly-mers studied in this work, pva and su-82 show the largest shift of the au localized surface plasmon resonance (lspr) band upon the incremental heating as well as the highest plasmonic sensitivity. it is thought that the thermal manipulation be a useful method for increasing the plasmonic sensitiv-ity of a platform. the results of this work will be helpful in selecting the best material for microfluidic sensing experiments.