We report on the immobilization of gold nanoparticles on end-functionalized and solvent responsive polystyrene brushes, grafted on an underlying substrate. The presence of gold nanoparticles on polystyrene brushes was confirmed by atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). The resulting polystyrene−Au nanoassemblies have been used as the nanosensors for the detection of a variety of organic solvents in surrounding media. The sensing mechanism is based upon the change in the proximity of the immobilized gold nanoparticles as a consequence of the solvent induced reversible swelling−deswelling of polystyrene chains. The sensing ability was demonstrated by a simple analytic tool, i.e., UV−vis spectroscopy, through a shift in plasmon resonance band of immobilized Au nanoparticles. A dramatic blue shift of 32 nm in the surface resonance band was observed as the surrounding media of Au immobilized polystyrene brushes (Au−PS) was changed from air to the toluene. The described approach is facile and versatile in nature, which can be used for the fabrication of a variety of nanosensors based on the polymer brushes−nanoparticle assemblies.

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A simple, fast, and versatile approach to the fabrication of outstanding surface enhanced Raman spectroscopy (SERS) substrates by exploiting the optical properties of the Ag nanoparticles and functional as well as organizational characteristics of the polymer brushes is reported. First, poly(2‐(dimethylamino)ethyl methacrylate) brushes are synthesized directly on glassy carbon by self‐initiated photografting and photopolymerization and thoroughly characterized in terms of their thickness, wettability, morphology, and chemical structure by means of ellipsometry, contact angle, AFM, and XPS, respectively. Second, Ag nanoparticles are homogeneously immobilized into the brush layer, resulting in a sensor platform for the detection of organic molecules by SERS. The surface enhancement factor (SEF) as determined by the detection of Rhodamine 6G is calculated as 6 × 106.

The present study reports on a versatile method of the preparation of polystyrene−ZnO composite particles with core−shell or raspberry-like morphology. SEM analysis revealed that ZnO has been deposited on the surface of functionalized polystyrene beads as either a continuous thin layer or small clusters, depending on the reaction parameters. We propose that the interaction between ZnO nanoparticles and β-diketone groups, present on the surface of polystyrene beads, is the driving force for the preparation of these composite particles. IR spectroscopy was used to prove the interaction between ZnO nanoparticles and β-diketone groups. X-ray diffraction of the PS/ZnO particles revealed diffraction peaks corresponding to wurtzite ZnO crystalline phase. TGA results demonstrated that the ZnO contents of composite particles can be varied by changing the concentration of Zn(Ac)2·2H2O salt prior to reaction. The composite particles produced are envisioned to have applications as the building blocks for fabrication of sensors, transducers, actuators, UV detectors, and optoelectronic devices.

In this study, we report on the fabrication of the nanoassemblies consisting of the poly(N-isopropyl acrylamide) (PNIPAAm) brushes immobilized with gold nanoparticles (Au NPs). The employed process involves grafting of the carboxyl terminated PNIPAAm chains on an underlying substrate in a brush conformation followed by the immobilization of surface functionalized Au NPs by means of physical interaction (hydrogen bonding). Atomic force microscopy (AFM), X-ray photoelectron spectroscopy (XPS), and UV-vis spectroscopy have been employed to characterize the prepared PNIPAAm-Au nanoassemblies. Polymer brushes have been found to suppress the nanoparticles' aggregation and, hence, facilitate the complete surface coverage. Furthermore, we demonstrated the application of resulting PNIPAAm-Au nanoassemblies in the fabrication of the temperature nanosensors. The employed approach is simple and highly versatile for the modification of macroscopic surfaces with a wide range of NPs.

In the present study, we report a method for preparing a fluorescent thermosensitive hybrid material based on monodisperse, thermosensitive poly( N-isopropyl acrylamide) (PNIPAM) microgels covered with CdTe nanocrystals of 3.2 nm diameter. The CdTe nanocrystals were covalently immobilized on the surface of PNIPAM microgels. The chemical environment around the CdTe nanocrystals was modified by changing the temperature and inducing the microgel volume-phase transition. This change provoked a steep variation in the nanocrystal photoluminescence (PL) intensity in such a way that when the temperature was under the low critical solution temperature (LCST) of the polymer (36 degrees C) the PL of the nanocrystals was strongly quenched, whereas above the LCST the PL intensity was restored.

A facile approach for the fabrication of hierarchically nanostructured hollow spheres composed of mixed metal oxides (ZnO−TiO2) has been demonstrated. The employed protocol involves coating of the functionalized polystyrene (PS) template beads with the successive layers of ZnO and TiO2 nanoparticles, respectively, followed by the calcination of resulting PS/ZnO−TiO2 core shell composite particles at elevated temperature. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) have been employed to evidence the fabrication of the monodisperse, intact, and closed ZnO−TiO2 hollow spheres. Presence of both ZnO and TiO2 phases in the ceramic shell of resulting hollow spheres has been confirmed by electron energy loss mapping analysis. Phase purity of the ZnO and TiO2 phases of the ceramic shell has been studied by X-ray diffraction analysis. Brunauer−Emmett−Teller (BET) method reveals the specific surface area and the average pore diameter of hollow spheres as 59.63 m2/g and 3 nm, respectively. Photocatalytic properties of the fabricated ZnO−TiO2 hollow spheres has been investigated for the degradation of organic dyes and compared with those of ZnO and TiO2 hollow spheres.

In recent years, a variety of nano-(micro) scale organic-inorganic composite particles with well defined chemical composition, size and morphology have been fabricated and their applications in wide spectrum of cutting-edge technological areas have been explored. This review is focused on recent developments towards various fabrication methodologies and applications of such colloid based composite particles. Strategies for preparation of nano and micro scale composite materials are presented by choosing as examples hard core based composite particles having core-shell and raspberry-like morphologies and soft core based composite microgels. Applications of these materials in wide range of potential areas are discussed including the fabrication of colloidal crystal arrays, hollow spheres, superhydrophobic surfaces, filler carriers and smart nanomaterials.