Photo-Sensitive and Degradable Polymeric Nanocapsules from Hyperbranched Poly(Amine Ester) Grafted Nano-Silica Templates

A facile approach for the preparation of the photo-sensitive and degradable polymeric nanocapsules containing a number of hydroxyl groups was developed. The hyperbranched poly(amine ester) grafted silica nanoparticles (SN-HPAE) were cross-linked with 4,4´-Azobenzene dibenzoyl chloride (ADC) by the reaction between the hydroxyl groups and benzoyl chloride groups. Then the silica templates were removed by being etched with HF to produce the photo-sensitive and degradable polymeric nanocapsules. The hollow structure of the polymeric nanocapsules with the inner diameter in the range of 20-100 nm was characterized by transmission electron microscopy (TEM). The solid-state UV-vis spectra of the cross-linked hyperbranched polymeric nanocapsules showed the photoresponsive behavior of the azobenzene type molecules.