(2013) Well-defined poly(N-isopropylacrylamide) with a bifunctional end-group: synthesis, characterization, and thermoresponsive properties, Designed Monomers and Polymers, 16:5, 465-474, DOI: 10.1080/15685551.2012 In this study, well-defined poly(N-isopropylacrylamide) (PNIPAM) with a bisalkyne end-group was synthesized by reversible addition-fragmentation chain transfer polymerization using 2-(2-(ethylthiocarbonothioylthio)-2-methylpropanoyl-oxy)ethyl 3,5-bis(prop-2-ynyloxy) benzoate (EMEB) as the chain transfer agent. The molecular weight and polydispersity index of polymer was determined by gel permeation chromatography (GPC). The linear increase in molecular weight with conversion, unimodal, and almost symmetrical peak in GPC trace together with low polydispersity indicated the controlled polymerization process of NIPAM mediated by EMEB. Subsequently, the Cu(I)-catalyzed [3 + 2] Huisgen cycloaddition between the end-group of polymer and azide derivatives was carried out to produce PNIPAM, in which the bisfunctional end-group was modified with phenyl, octyl, amido, and hydroxyl groups. After completing the click reaction, the structure of the polymer was characterized carefully by Fourier transform infrared spectroscopy (FTIR), 1 H NMR, and Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF-MS), indicating the complete consumption of alkyne end-groups. In addition, almost no change in molecular weight as well as the polydispersity was observed by comparison with the GPC traces of polymers before and after click reaction. The cloud point temperatures (T cp s) of the resulting PNIPAM derivatives in aqueous solution were investigated in detail by dynamic light scattering. The results showed that the values of T cp were ranged from 22 to 38°C, which depended largely on end-groups as well as the polymer molecular weights.

In this study, a novel vinyl polymer containing 2,4,5-triphenylimidazole side groups was synthesized through conventional radical polymerization, which possesses the characteristic of temperature-dependent absorbance in the near-ultraviolet (UV) spectral region. The linear dependence of UV absorbance on temperature was confirmed for the polymer both in solid state and in solution by experiment and also supported by the results of theoretical investigation.

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The self-assembly of organic 1-(2-pyridylazo)-2-naphthol (PAN) into hierarchical architectures, such as microfibers, microrods, and sheaflike structures, in solution was successfully achieved by reprecipitation method with the assistance of thermoresponsive diblock copolymer poly(N,N-dimethylacrylamide)-b-poly(N-isopropylacrylamide) (PDMA-b-PNIPAM). It was found that the morphology modification can be readily controlled by varying the polymer concentrations. The optical absorption and fluorescence emission properties of the as-prepared PAN architectures were investigated. Time-dependent spectra of the precipitating solution for sheaflike structures formation were measured to monitor the self-assembly process of PAN molecules. The results showed that the PAN microstructures exhibited intense fluorescence emission, indicating an unusual aggregation-induced emission enhancement (AIEE) phenomenon for PAN, which have great potential for future use in optoelectronic microdevices

In this study, a self-assembly technique assisted with thermoresponsive diblock copolymer poly(N,N-dimethylacrylamide)-b-poly(N-isopropylacrylamide) (PDMA-b-PNIPAM) is developed to fabricate crystalline microtubes of 2-(49-((49-vinylbenzyl)oxyl)phenyl)-4,5-diphenylimidazole (VPD). The as-prepared VPD microtubes are identified to have a hollow tubular structure with a rectangular cross section. All the obtained microtubes under optimal conditions have a uniform size of 220 nm in diameter, 20 nm in wall thickness, and 4.5 mm in length. Additionally, the length of the VPD microtubes can be readily controlled by adjusting the concentration of VPD. Furthermore, the VPD microtubes exhibit interesting size-dependent optical properties, of which the UV-vis absorption band shows an obvious red shift compared to that of the monomer. These results should be significant in triphenylimidazole derivative crystallization and their potential applications in optoelectronic devices.