Physicochemical characterization of the comb-type pyridine-co-poly(ethylene glycol) copolymer at the interface

The novel amphiphilic comb-type copolymers were synthesized by copolymerization of a unit A that contains a pyridine (Py) portion and a unit B that contains a poly(ethylene glycol) (PEG) portion. The obtained copolymers consist of methoxy-endend PEG as a hydrophiphilic segment and Py as a hydrophobic and metal affinity segment (Py-co-PEG). Py-co-PEGs formed micelles and their physicochemical properties were intensively investigated in terms of critical micelle concentration, pyrene solubilization, and micelle size distribution. Furthermore, the gold nanoparticles (Au-NPs) were prepared using the Py-co-PEG polymeric micelles. Py-co-PEG has attained the long term interfacial stability by employing the multi-point adsorption of the Py unit on the gold surface, although usually prepared Au-NPs by thiol derivative are well-known to readily lose the dispersion stability under physiological and oxidative condition. It is important to note that Au-NPs protected by Py-co-PEG were drastically enhanced their dispersion stability under high ionic physiological and air oxidative conditions.