Xinke Sun

Photocatalytic Activity of Heterostructures Based on TiO2 and Halloysite Nanotubes

A one-step solvothermal method was used to prepare TiO(2)/halloysite composites. TiO(2) nanoparticles were deposited on the platform of the halloysite nanotubes (HNTs). XRD, FT-IR, FE-SEM, and TEM were applied to investigate the structures and morphologies of the resultant samples. The as-prepared TiO(2)/HNTs photocatalyst exhibits pH sensibility on the degradation of methanol and a higher photocatalytic activity on the degradation of acetic acid. The combination of the photocatalytic property of TiO(2) and the unique structure of halloysite endowed this material with a bright perspective in degradation of organic pollutant.

CuO/TiO2 nanocrystals grown on graphene as visible-light responsive photocatalytic hybrid materials

CuO/TiO2 nanocrystals grown on graphene (CuO/TiO2–GR) were prepared by a simple hydrothermal method using Cu(CH3COO)2·H2O and (NH4)2TiF6 as precursors and graphene oxide (GO) as templates. The as-prepared composites were characterizated by TEM, XRD, FT–IR to determine composition and phase purity. The photocatalytic activity of the samples was evaluated by photo-degradation of methylene blue (MB) aqueous solution under UV and visible light illumination. This work may provide new insights into preparing other inorganic graphene-based composites.

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.

pH- and Thermo-Sensitive Co-polymers Based on a Hyperbranched Polymers Core as Encapsulation and Release Carriers for Guest Molecules

Hyperbranched poly(3-ethyl-3-(hydroxymethyl)oxetane) (HPBO), modified by S-1-dodecyl-S′-(α, α-dimethyl-α′′-acetic acid) trithiocarbonate (DMP) to form a RAFT macroinitiator, and then two monomers, 2-(dimethylamino)ethyl-methacrylate (DMAEMA) and acrylic acid (AA), were polymerized to obtain novel pH- and thermo-sensitive polymers with a hyperbranched polymer core. These polymers exhibited phase transitions in response to pH and temperature. They were possible to harvest a bioactive molecule, indometacin, from solution using the phase transition of these pH- and thermo-sensitive polymers. Various parameters, such as percent loading of drugs, pH, temperature and nature of the release media on the release profiles, were investigated. The resultant polymer carriers can potentially be used for the controlled release of the anti-inflammatory drug indometacin.

Preparation of Biomimetic Zwitterionic Core Cross-Linked Nanocarriers for Control Release of Bioactive Agents

Biomimetic core cross-linked nanocarriers (CCL-NCs) with zwitterionic shell was constructed from an amphiphilic block copolymer poly(2-(dimethylamino) ethyl methacrylate-co-carboxybetaine)-b-polystyrene ((PDMAEMA-co-PCB)-b-PS) via mini-emulsion RAFT polymerization. CCL-NCs present in this report possess properties of redox-sensitivity, limited unspecific protein adsorptions and low cytotoxicity, which highly enhance their potential application in drug delivery. Morphology of CCL-NCs was characterized by transmission electron microscopy (TEM) and dynamic light scattering (DLS) measurements. The control release process has also been investigated under three different conditions with or without dithiothreitol (DTT) at pH 5.4, 6.5 and 7.4.

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.

A Novel Fission Process in Mini-emulsion RAFT Polymerization: Shell Crosslinked Nanoparticles as a Model

Shell crosslinked nanoparticles, prepared from copolymerization of styrene and disulfide crosslinker, using poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) as stabilizer and macroinitiator, exhibited a special fission behavior during the mini-emulsion RAFT polymerization process.

Straightforward synthesis of hyperbranched polymer/graphene nanocomposites from graphite oxide via in situ grafting from approach

The grafting of graphite oxide (GO) with cyclic ether monomers, directly affords grafting with hyperbranched polymers. The resulting nanocomposites show good solubility in the solvents of polymers, exfoliation of graphene in the polymer matrix and excellent mechanical properties and robustness under bending.