Rongbai Tong

Synthesis, Characterization and Properties of Some Main-Chain Ferrocene-Based Polymers Containing Aromatic Units

Four main-chain ferrocene-based polymers containing aromatic units, including poly(o-Cresolphthalein 1,1′-ferrocene dicarboxylate) (PCPFD), poly(cresol red 1,1′-ferrocene dicarboxylate) (PCRFD), poly(2,4-quinolinediol 1,1′-ferrocene dicarboxylate) (PQDFD), and poly(sudan orange G 1,1′-ferrocene dicarboxylate) (PSOFD), were successfully synthesized. The solution polycondensation reaction was employed for the synthesis of PCPFD and PCRFD while PQDFD and PSOFD were synthesized via an interfacial polycondensation reaction. The synthesized polymers were characterized by 1H and 13C NMR, UV–VIS absorption and FTIR spectra and X-ray diffraction. The synthesized main-chain ferrocene-based polymers are generally amorphous. The effect of organic solvent, scan rate, electrolyte concentration and [Fe] concentration on the cyclic voltammetric behavior of the synthesized polymers were examined. The thermal properties were investigated employing thermogravimetric analysis. The results revealed the relative thermal stability of the polymers. The liquid crystalline properties were studied. The results indicated that the synthesized polymers exhibited nematic phases during the scan cycles of heating and cooling with high phase duration.

Redox and Temperature Dual Responsive Gel Based on Host–Guest Assembly

Stimuli-responsive hydrogels undergo shape transformation in response to change in ambient environment and have potential applications in tissue engineering, robotics, actuator and biosensing. Generally, the Stimuli-responsive hydrogels are controlled by unique external stimuli and the response is also specific. Here, we developed redox-regulated and temperature responsive macroscopic gel assembly system, using polyacrylamide-based hydrogel, which was functionalized with ferrocene (Fc) as a guest hydrogel and poly(N-isopropylacrylamide) (PNIPAAm) gel modified with β-cyclodextrin as a host hydrogel. It was observed that the variations in the redox potential induced reversible assembly/dissociation transition in a bi-gel strip and optimization of βCD contents provided fast bending speed and large bending degree, which can be applied to develop temperature sensitive switch.

Stimuli-responsive HBPS-g-PDMAEMA and its application as nanocarrier in loading hydrophobic molecules

Summary The topic of stimuli-responsive nanocarriers for loading guest molecules is dynamic. It has been widely studied in applications including drug controlled release, smart sensing, catalysis, and modeling. In this paper, a graft copolymer (hyperbranched polystyrene)-g-poly[2-(dimethylamino)ethyl methacrylate] (HBPS-g-PDMAEMA) was synthesized and characterized by 1H NMR and GPC. It was observed that the star-like HBPS-g-PDMAEMA formed aggregates in aqueous solution. The influence of polymer concentration, ionic strength and pH value on the aggregates in aqueous solution was investigated by using UV–vis spectroscopy and DLS analysis. The results showed that size of aggregates was affected by a corresponding stimulus. In addition, the loading ability of HBPS-g-PDMAEMA aggregates was investigated by using pyrene or Nile red as the model guest molecules by using UV–vis and fluorescence spectroscopy. The results showed that HBPS-g-PDMAEMA aggregates were capable to encapsulate small hydrophobic molecules. These newly prepared HBPS-g-PDMAEMA nanocarriers might be used in, e.g., medicine or catalysis.