Exfoliated graphite oxide (GO) sheets with hydroxyl groups and amine groups on the surface were prepared by modification of graphite. Atom transfer radical polymerization (ATRP) initiator molecules were grafted onto the GO sheets by reactions of 2-bromo-2-methylpropionyl bromide with hydroxyl groups and amine groups. Poly(2-(dimethylamino)ethyl methacrylate) (PDMAEMA) chains on the surface of GO sheets were synthesized by in-situ ATRP. X-ray photoelectron spectroscopy, thermogravimetric analysis, and transmission electron microscopy (TEM) results all demonstrated that polymer chains were successfully produced. After grafting of PDMAEMA, the dispersity of GO sheets in solvents was improved significantly. Poly(ethylene glycol dimethacrylate-co-methacrylic acid) particles were deposited on GO sheets via hydrogen bonding between MAA units on polymer particles and amine groups of PDMAEMA. TEM and scanning electron microscopy were used to characterize the structure of the nanocomposites.

Two well-defined amphiphilic asymmetric macromolecular brushes, one bearing hydrophilic poly(ethylene glycol) (PEO) and hydrophobic polystyrene (PS) side chains on poly(glycidyl methacrylate) (PGMA) backbone and the other bearing pendant PEO and poly(styrene-block-N-isopropylacrylamide) (PS-b-PNIPAM) block copolymer side chains, were synthesized by grafting from approach based on a combination of click chemistry and in situ reversible addition−fragmentation chain transfer (RAFT) polymerization. PGMA backbone was synthesized by atom transfer radical polymerization (ATRP), and a polymer backbone with pendant hydroxyl and azide groups (PGMA−OH/N3) was obtained after ring-opening reaction of the epoxide rings on PGMA. RAFT chain transfer agent (CTA) was introduced to the polymer backbone by facile click reaction between alkyne-terminated RAFT CTA and PGMA−OH/N3. PEO side chains were grafted onto the polymer backbone by esterification between carboxyl end group of PEO and hydroxyl group on the polymer backbone; PS or PS-b-PNIPAM side chains were prepared by RAFT polymerization. Gel permeation chromatograph, FTIR and 1H NMR results all indicated successful synthesis of well-defined amphiphilic asymmetric macromolecular brushes. The self-assembly of the macromolecular brushes in solutions was also investigated in this research. Asymmetric macromolecular brushes with PEO and PS side chains self-assembled into vesicle structures in methanol. PS side chains were in the walls of the vesicles, and PEO side chains were in the coronae. The average size of the structure increased with PS chain length. The macromolecular brushes with PEO and PS-b-PNIPAM block copolymer side chains were able to self-assemble into vesicles in aqueous solution. Temperature exerted a significant effect on the morphology of the structures. At a temperature above lower critical solution temperature (LCST) of PNIPAM, the size of the vesicles decreased due to the shrinking of PNIPAM blocks in the corona.

A novel preparation method of CdS nanoparticles with controllable size and stability is presented. Poly(styrene-block-2-vinylpyridine) (PS-b-P2VP) and cadmium ions form aggregates of single micelles called compound micelles, upon addition of the cadmium acetate salt into a solution of the block copolymer in tetrahydrofuran. The growth of CdS nanoparticles is confined to the core of single micelles after introduction of hydrogen sulfide gas into the solution. UV−visible spectroscopy, fluorescence spectroscopy, and transmission electron microscopy were employed to characterize the prepared nanoparticles. UV−visible absorption spectra show that larger nanoparticles are produced at lower 2VP:Cd2+ molar ratio. UV−visible absorption spectra and fluorescence spectra both indicate that with a decrease of block copolymer concentration in tetrahydrofuran, the size of the CdS nanoparticles decreases. The stability of the CdS nanoparticles and micelles was also investigated. UV−visible results show that the prepared CdS nanoparticles have good colloidal stability.

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Shape amphiphiles with distinct shapes and amphiphilic properties can be used as fundamental building blocks in the fabrication of novel structures and advanced materials. In this research synthesis and selfassembly of monotethered single-chain nanoparticle shape amphiphiles are reported. Poly(2-(dimethylamino)ethyl methacrylate)-block-polystyrene (PDMAEMA-b-PS) was synthesized by two-step reversible addition− fragmentation chain transfer (RAFT) polymerization. The PDMAEMA blocks were intramolecularly cross-linked by 1,4-diiodobutane (DIB) at significantly low concentrations, and PS-tethered PDMAEMA single-chain nanoparticles were prepared. Gel permeation chromatograph, 1 H NMR and transmission electron microscopy results all indicated successful synthesis of the structures. The controlled self-assembly of the shape amphiphiles in selective solvents was investigated. Depending on the size of the single-chain nanoparticles, the shape amphiphiles self-assemble into strawberry-like micelles, a structure with single-chain nanoparticles in the corona and PS in the core, or vesicles in aqueous solutions. Similar to the self-assembled structures in aqueous solution, the morphology of the aggregates in methanol changes from micellar structure to vesicular structure with the decrease of the PDMAEMA single-chain nanoparticles size. In cyclohexane, the shape amphiphiles self-assemble into bunchy micelles with single-chain nanoparticles in the cores and linear PS in the coronae.