A novel conducting polymer, poly(aniline-co-p-aminobenzoic acid) (PAABA), was successfully synthesized via electrochemical copolymerization of aniline and p-aminobenzoic acid (p-ABA) in 2 M H2SO4 solution. The results of FTIR and SEM revealed the differences between the obtained copolymer and its two corresponding homopolymers. Compared to polyaniline which has a rather limited useful pH range, PAABA presents excellent redox activity from pH < 1.0 to pH 10.0. The ion exchange properties of the copolymer were also investigated by using electrochemical quartz crystal microbalance (EQCM) and cyclic voltammetry, demonstrating a special anion exchange behavior different from polypyrrole. In other words, the spatial structure of anions instead of the radius of anions studied plays a key role in the anion exchange affinity sequence.
Reduction-responsive micelles hold enormous promise for application as drug carriers due to the fast drug release triggered by reducing conditions and high anticancer activity. However, the effect of hydrophobic chain length on the stability and guest exchange of reduction-responsive micelles, especially for the micelles formed by diblock copolymers containing single disulfide group, is not fully understood. Here, shell-sheddable micelles formed by a series of disulfide-linked copolymer poly(ethylene glycol)-b-poly(ε-caprolactone) (PEG–SS–PCL) containing the same chain length of PEG but different chain lengths of hydrophobic block PCL were prepared and well characterized. The influence of the chain length of hydrophobic PCL block on the stability and guest exchange of PEG–SS–PCL micelles was studied by the use of both dynamic laser light scattering (DLS) and fluorescence resonance energy transfer (FRET). The results show that longer PCL chains lead to a slower aggregation rate and guest exchange of micelles in the aqueous solutions containing 10 mM dithiothreitol (DTT). The cell uptake of the shell-sheddable PEG–SS–PCL micelles in vitro shows that the amount of internalization of dyes loaded in PEG–SS–PCL micelles increases with the chain length of hydrophobic PCL block investigated by flow cytometric analysis and confocal fluorescence microscopy.
危险品化学品经营许可证（带存储）