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In this study, hybrid substrates composed of poly( N -isopropylacrylamide) hydrogels and Au nanorods (PNIPAM@AuNRs) that exhibit tunable plasmon coupling are designed and fabricated. In this process, Au NRs are deposited on the surface of a PNIPAM hydrogel, and the temperature is increased, causing the hydrogel template to shrink, thereby driving the Au NRs closer to each other. The resulting surface plasmon resonances (SPR) of the composite are observed as a large red-shift. The formation of more hot spots increases the already high sensitivity of surface-enhanced Raman scattering (SERS) detection, and the tunable optical properties enable closer matching of the laser to the near-infrared excitation required. Moreover, these hybrid substrates can be conveniently identified by optical microscopy, enabling in situ SERS detection with high sensitivity and reproducibility.

A series of inorganic/organic nanocomposites were prepared by blending cage-like, hydroxyl-bearing polyhedral oligomeric silsesquioxane (HO–POSS) with poly(methyl methacrylate) (PMMA) in THF solvent. Fourier transform infrared spectrophotometry (FTIR) and 29Si–nuclear magnetic resonance (29Si-NMR) were employed to characterize the structures of the HO–POSS/PMMA nanocomposites. Scanning electron microscope (SEM) images showed that the as-prepared composite films were smooth, and no severe aggregation of HO–POSS was observed when POSS content was less than 1.0 wt.%. Thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) results showed that the incorporation of small amount of nanosized HO–POSS reinforced the thermal stability of PMMA. When 1.0 wt.% of HO–POSS was incorporated into PMMA matrix, the Tg and Td increased by 28.8 °C and 18.9 °C, respectively, due to the strong interaction between POSS cages and PMMA chains. However, higher POSS contents (>2.0 wt.%) deteriorated the thermal and mechanical properties of the nanocomposites owing to the phase separation in the composite matrix caused by the aggregation of POSS cages.

A series of poly(vinyl pyrrolidone-co-octavinyl polyhedral oligomeric silsesquioxanes) (PVP-POSS) organic–inorganic hybrid nanocomposites containing different percentages of POSS were prepared via free radical polymerization and characterized by FTIR, high-resolution 1H-NMR, solid-state 29Si-NMR, GPC, DSC, and TGA. POSS contents in these nanocomposites can be effectively controlled by varying the POSS feed ratios which can be accurately quantified by FTIR curve calibration. On the basis of 29Si-NMR spectra, average numbers of reacted vinyl groups of each octavinyl-POSS macromer are calculated to be 5–7, which depends on POSS feed ratios. Both GPC and DSC results indicate that these nanocomposites display network structure and the degree of crosslinking increases with the increase of the POSS content. The incorporation of POSS into PVP significantly improves their thermal properties (Tg and Tdec) primarily due to crosslinking structure and dipole–dipole interaction between POSS cores and PVP carbonyl groups. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2009

The poly(styrene-co-octavinyl-polyhedral oligomeric silsesquioxane) (PS–POSS) organic–inorganic hybrid nanocomposites containing various percent of POSS were prepared via one-step free radical polymerization and characterized by FTIR, high-resolution 1H NMR, 29Si NMR, GPC, DSC, and TGA technologies. The POSS contents in these nanocomposites were determined using FTIR calibration curve. The result shows that the POSS contents in nanocomposites can be tailored by varying the POSS feed ratios. On the basis of the POSS contents in the nanocomposites and the 1H NMR spectra, the number of reacted vinyl groups of each octavinyl-POSS macromonomer were calculated to be 6–8. DSC and TGA measurements indicate that the incorporation of POSS into PS homopolymer can apparently improve the thermal properties of the polymeric materials. The dramatic Tg and Tdec increases are mainly due to the formation of star and low cross-linking structure of the nanocomposites, where POSS cores behave as the joint points and hinder the motion and degradation of the polymeric chains. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007

A new class of organic-inorganic hybrid polymers with well-defined structure was prepared by reacting diepoxyhexavinyl polyhedral oligomeric silsesquioxanes (DehvPOSS) with diamines of different chain lengths. The structures and properties of these hybrid polymers were well characterized by FTIR, 29Si-NMR, GC-MS, and TGA. A modeling characterization was employed to help identify the structures of organic tethers linked between the POSS cages. The results indicated that at the stoichiometric ratio of DehvPOSS to diamine, well-defined organic–inorganic hybrid polymers with controlled variation of the organic tether architecture can be made, and each organic tether connected four POSS cages. Thermal stability (Tdec) increased with an increase in the tether length of the diamine molecules, and the highest Tdec was obtained with butanediamine (rather than propanediamine or ethanediamine) as the organic tether. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 3730–3735, 2006