A General Nanocoating Method via Photoinduced Self-Initiation

Abstract

Hybrid core–shell nanoparticles play a very significant role in many applications. Here, we report a light-induced oligomer coating on nanoparticles via Norrish type I reaction. The radical species generated via UV irradiation can chemically initiate the photoinitiators, which are then polymerized and deposited on inorganic nanoparticles via heterogeneous nucleation, forming a soft oligomer coating smaller than 40 nm. This coating method is versatile and potentially applicable to many different types of inorganic cores and their assemblies, making it a very useful technique for “freezing” nanoassemblies in solution. Moreover, these oligomer coatings containing radical species can also initiate surface polymerization of both styrenic and acrylic monomers with certain functionalities for different applications such as self-assembly, plasmon tuning, and pH sensing (3.5–4.5).

Light-Programmed Bistate Colloidal Actuation Based on Photothermal Active Plasmonic Substrate

“…Extra layer of PNIPAM was post-polymerized to fully fill the pores of AAO templates [ 57 ]. Specifically, 50 μl of mixture containing 47.5 μl of NIPAM (2 M) and 2.5 μl of HMPP (1 μl/ml) was dripped on the samples, followed by ultraviolet irradiation (302 nm) for 15 min [ 58 ]. Extra unbounded PNIPAM was removed by repeated washing with large amount of DI water and ethanol, leaving a ~300-nm overlayer on top.…”