Guohua Jiang

Facile one-pot preparation of novel shell cross-linked nanocapsules: inverse miniemulsion RAFT polymerization as an alternative approach

A series of novel shell cross-linked nanocapsules were facilely fabricated in an inverse miniemulsion reversible addition–fragmentation chain transfer (RAFT) system, in which poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) acted as a stabilizer and macroinitiator. The as-prepared nanocapsules with PDMAEMA cores and poly(methylacrylic acid) (PMAA) shells, had a size of 220 nm and can be used as a carrier for the encapsulation of hydrophilic components such as inorganic salts.

Facile one-pot approach for preparing fluorescent and biodegradable hyperbranched poly(amidoamine)s

Hyperbranched poly(amidoamine)s were synthesized by Michael addition of 1-(2-aminoethyl) piperazine (AEPZ) and methyl acrylate (MA). The resultant polymers can emit bright blue fluorescence intensity under excitation wavelength and their degradability depended on the environmental pH value.

Preparation of shell cross-linked nanoparticles via miniemulsion RAFT polymerization

Shell cross-linked polymeric nanoparticles were prepared through an interfacially confined copolymerization of styrene and disulfide cross-linker in a reversible addition-fragmentation chain transfer (RAFT) miniemulsion system using poly(2-(dimethylamino) ethyl methacrylate) (PDMAEMA) as stabilizer and macroinitiator. 1H NMR, FT-IR, and FE-SEM have been applied to investigate the structures and morphologies of the resultant nanoparticles. Fluorescent spectra results show that the as-prepared samples have fluorescent properties, which may be used as a fluorescent carrier for control release of guest molecules.

Synthesis and fluorescence properties of hyperbranched poly(amidoamine)s with high density tertiary nitrogen

Hyperbranched poly(amidoamine)s with high density tertiary nitrogen (HPAMAMs-OH) were prepared via the two-step reactions. Firstly, hyperbranched poly(amidoamine)s (HPAMAMs) were synthesized by Michael addition of 1-(2-aminoethyl) piperazine (AEPZ) and methyl acrylate (MA) and then alkylation of the residual amino protons of hyperbranched poly(amidoamine)s (HPAMAMs) with propylene oxide (PO) in ethanol was performed. The fluorescence properties of HPAMAMs and HPAMAMs-OH were investigated. It was found that the fluorescence intensity of the polymers increased correspondingly with the increasing of the tertiary nitrogen in the molecular structure. The tertiary nitrogen with lone pair electrons inside the molecular structure played an important role in the photoluminescence. The complex with nano gold encapsulated in the interior of the HPAMAMs-OH presented greatly enhanced emission. Those results show that the nano gold may be used to adjust the fluorescence properties of HPAMAMs-OH and may extend potential applications of HPAMAMs-OH and gold nanoparticles.

Wet photochemical filling: a new low-diameter tube-filling method based on differentiated nanotube surfaces

In this work, by using a simple chemical morphology freezing method novel low-diameter tubular nanocomposites (TiO2–NTs@SiO2) with differentiated surfaces are prepared, in which the TiO2 layer acts as a photoactive inner surface and the SiO2 layer acts as an insulating outer surface. Because of the photoactivity of TiO2, under UV light irradiation, only the inner TiO2 surface can photoreduce a H2PtCl6 precursor solution to Pt nanoparticles on its surface. As a result, Pt nanoparticles are highly selectively filled in the tube inner channel after this wet photochemical filling process. Due to the high dispersity of Pt nanoparticles in the channel, the method can improve catalytic activity efficiently by increasing the ultimate effective Pt load. In photocatalytic H2-production experiments, nanotubes filled with 6 wt% Pt show the highest photoactivity of all the samples; this activity is twice that obtained with TiO2 nanoparticles loaded with 0.6 wt% Pt.