Novel photosensitive azopolymer brushes were synthesized via surface initiated atom transfer radical polymerization using initiator self-assembled on Au surface. The chemical structures of azobenzene derivatives were confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance spectroscopy (NMR). The surface morphology of azopolymers via atom transfer radical polymerization (ATRP) for different time was investigated by atomic force microscopy (AFM). Additionally, the photoisomerization of azopolymer was measured by ultraviolet-visible spectroscopy (UV-Vis). The results indicate that such azopolymers can undergo trans-cis-trans photoisomerization efficiently by photo-irradiation with UV light. Furthermore, this photoisomerization property could also induce the reversible adsorption of bovine serum albumin (BSA) adsorption on azopolymer brush surfaces. This adsorption kinetics of the reversible process can be measured by surface plasmon resonance (SPR) spectroscopy in situ. It suggests that the protein biochips could be regenerated safely by UV irradiation rather than by being rinsed with chemical reagents.

A new titanium (IV) complex bearing phenoxyimine-fluorene ligand was prepared and its behaviors in ethylene homo- and copolymerization with 1-hexene, 1-octene, and norbornene in the presence of modified methylaluminoxane (MMAO) were studied respectively. The effects of various polymerization conditions including polymerization temperature, ethylene pressure and the concentration of comonomer on the catalytic activities and properties of the resultant polymer were investigated. The broad molecular weight distribution of resulting polymer indicated that the multiple active species were formed during polymerization. Such complex showed good catalytic activities in ethylene homo- and copolymerizations and good capabilities of incorporating various comonomers into polyethylene backbone. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1617–1621, 2010

The design and synthesis of well-defined polymethylene-b-polystyrene (PM-b-PS, M_n = 1.3 × 10⁴–3.0 × 10⁴ g/mol; M_w/M_n (GPC) = 1.08–1.18) diblock copolymers by the combination of living polymerization of ylides and atom transfer radical polymerization (ATRP) was successfully achieved. The ¹H NMR spectrum and GPC traces of PM-b-PS indicated the successful extension of PS segment on the PM macroinitiator. The micellization behavior of such diblock copolymers in tetrahydrofuran were characterized by dynamic light scattering (DLS) and atomic force microscopy (AFM) techniques. The average aggregate sizes of PM-b-PS diblock copolymers with the same length of PM segment in tetrahydrofuran solution (1.0 mg mL⁻¹) increases from 104.2 nm to 167.7 nm when the molecular weight of PS segment increases. The spherical precipitated aggregates of PM-b-PS diblock copolymers with an average diameter of 600 nm were observed by AFM. Honeycomb porous films with the average diameter of 3.0 μm and 6.0 μm, respectively, were successfully fabricated using the solution of PM-b-PS diblock copolymers in carbon disulfide via the breath-figure (BF) method under a static humid condition. The cross-sections of low density polyethylene (LDPE)/polystyrene (PS)/PM-b-PS and LDPE/polycarbonate (PC)/PM-b-PS blends were observed by scanning electron microscope and reveal that the PM-b-PS diblock copolymers are effective compatilizers for LDPE/PS and LDPE/PC blends. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1894–1900, 2010

A combination of living polymerization of ylides and atom transfer radical polymerization (ATRP) was used successfully in the design and synthesis of well-defined polymethylene-b-poly(methyl methacrylate) (PM-b-PMMA) and polymethylene-b-poly(n-butyl acrylate) (PM-b-Pn-BuA). Tripolymethylene borane were firstly synthesized by living polymerization of dimethylsulfoxonium methylides and then oxidated quantitatively through trimethylamine-N-oxide dihydrate to provide a series of low-polydispersity hydroxyl-terminated polymethylenes (PM-OHs) with different molecular weight. Subsequently, such polymers were converted into polymethylene-based macroinitiators (PM-MIs, M_n(GPC) = 1900–10,400 g/mol; M_w/M_n = 1.12–1.23) in ∼100% conversion. ATRPs of methyl methacrylate and n-butyl acrylate were successfully conducted using PM-MI to produce well-defined diblock copolymers of PM-b-PMMA and PM-b-Pn-BuA, respectively. The GPC traces indicated the successful extension of PMMA and Pn-BuA segment (M_n(GPC) of PM-b-PMMA = 3980–10,100 g/mol; M_w/M_n = 1.16–1.22; M_n of PM-b-Pn-BuA = 7400–9200 g/mol; M_w/M_n = 1.14–1.18). Atomic force microscopy (AFM) was used to characterize the structures of the precipitated PM-b-PMMA micelles, which were formed in toluene. The blend of LDPE/PMMA was prepared with PM-b-PMMA as compatibilizer. The scanning electron microscopy (SEM) results showed that the compatibilization of the LDPE/PMMA was improved greatly by the incorporation of PM-b-PMMA. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 5671–5681, 2009