Photophysical Study of Pyrene-labelled St/DVB Copolymers

The photophysical properties of a series of pyrene-labelled styrene/divinyl benzene (St/ DVB) copolymers have been studied for the first time by steady-state fluorescence spectra. The results indicate that when pyrenyl content (mol%) in the copolymer is lower than 0. 006% , the fluorescence spectra only show the pyrenyl monomer emission, while the 0-0 transition band is much suppressed and the vibronic structure is partially lost. However, in the fluorescence spectra of the copolymers with pyrenyl content higher than 0.3%, there appear some new emission bands at ca 420 nm, 440 nm and 475 nm. These results are explained in terms of the formation of ground-state and excited-state aggregates, which reveals the heterogeneity of the crosslinked networks.     

Photoluminescence of Electrospun Poly-Methyl-Methacrylate:Alq3 Composite Fibres

Tris（8-hydroxyquinoline） aluminium doped poly-methyl-methacrylate （PMMA：Alq3） composite nanofibres are fabricated by electrospinning. The morphology of fibres is characterized by scanning electron microscopy. The photoluminescence of a series of the nanofibres with various contents of Alq3 to PMMA is investigated. UVvisible absorption and the PL spectra analysis are employed to analyse the interaction between the polymer and the luminescent molecule.     

聚(丙交酯-co-乙交酯)/β-磷酸三钙复合物的电纺研究

对生物可吸收聚(丙交酯-co-乙交酯)(poly(lactide-co-glycolide),PLGA)与β-磷酸三钙(-βTCP)复合物体系进行了电纺.研究了PLGA的浓度,-βTCP与PLGA比例,加料速度,电压,喷头与接收体之间的距离等因素对电纺过程的影响,制备出纳米纤维膜,并用扫描电镜(SEM)等对纤维膜进行表征.结果表明,电纺溶液浓度越高,或者加料速度越快,纳米纤维的直径越粗.力学实验显示,复合物中-βTCP的含量增加使纳米纤维膜的拉伸强度和杨氏模量下降.     

生物高分子静电纺丝研究进展

静电纺丝(电纺)技术是一种制备直径为数十纳米到数微米的纳米纤维的有效方法。由于生物高分子具有良好的生物相容性,近年来国内外对生物高分子的电纺制备进行了大量研究。这种生物高分子纳米纤维在组织工程支架、组织修复等方面有独特的优势。本文对生物高分子——多糖、蛋白质、核酸(DNA)的静电纺丝研究进行了总结。     

一些新的芘衍生物的合成及光物理研究

本文合成了一系列新的芘衍生物，用紫外光谱和稳态荧光光谱方法研究了它们的光物理性质。结果表明，取代烷基几乎不影响芘的吸收光谱，而使芘的荧光光谱振动精细结构消失或部分消失；取代甲酰基的芘衍生物的荧光发射强烈依赖于溶剂的性质，极性溶剂中荧光光谱无精细结构，且荧光发射峰随介质极性的增加而红移。     

Enhancing hydrophilicity and protein resistance of silicone hydrogels by plasma induced grafting with hydrophilic polymers

<正>The hydrophilicity of silicone hydrogels used as soft corneal contact lens plays an important role in wearing comfort.In order to enhance hydrophilicity and protein resistance,silicone hydrogel membranes were modified by atmospheric pressure glow discharge plasma(APGDP) induced surface graft polymerization of N-vinyl pyrrolidone(NVP) and poly(oligoethylene glycol methyl ether methacrylate)(PEGMA) in this paper.XPS analysis demonstrated the success of graft polymerization of NVP and PEGMA onto the surface of silicone hydrogel membranes.The hydrophilicity of silicone hydrogels was characterized by the measurement of water contact angle(WCA).The result showed that NVP grafted silicone hydrogel has the WCA of about 68°and PEGMA grafted silicone hydrogel has the lowest WCA of about 62°,while the pristine silicone hydrogel is hydrophobic with the WCA of about 103°.Protein resistance of silicone hydrogels was investigated by the method of bicinchoninic acid assay using bovine serum albumin(BSA) as a model.It's found that the grafted silicone hydrogel has a significant improvement of protein resistance,and PEGMA grafting is more efficient for the reduction of protein adsorption than NVP grafting.The silicone hydrogel membranes grafted with NVP and PEGMA are good candidates of soft corneal contact lenses.     

Antibacterial poly(D,L-lactide) (PDLLA) fibrous membranes modified with quaternary ammonium moieties

<正>Antibacterial poly(D,L-lactide)(PDLLA) fibrous membranes were developed via electrospinning,followed by surface modification which involved plasma pretreatment,UV-induced graft copolymerization of 4-vinylpyridine(4VP) and quaternization of the grafted pyridine groups with hexylbromide.The success of modification with quatemized pyridinium groups on the PDLLA fibrous membranes was ascertained by X-ray photoelectron spectroscopy(XPS).The antibacterial activities of these membranes were assessed against Gram-positive Staphylococcus aureus(S.aureus) and Gram-negative Escherichia coli(E.coli).The PDLLA fibrous membranes modified with quaternized pyridinium groups showed antibacterial efficiency against both bacteria as high as 99.999%.The results demonstrated that the antibacterial activity was based on the interaction of the positive charge of pyridinium group and negatively charged cell membrane of bacteria, resulting in loss of membrane permeability and cell leakage.