Composition and solution properties of fluorinated block copolymers and their surface structures in the solid state

A series of diblock copolymers composed of methyl methacrylate and 2-perfluorooctylethyl methacrylate (PMMA₁₄₄-b-PFMA _n ) with various PFMA block lengths were prepared by atom transfer radical polymerization (ATRP). The surface structures and properties of these polymers in the solid state and in solution were investigated using contact angle measurement, X-ray photoelectron spectroscopy (XPS), sum frequency generation (SFG) vibrational spectroscopy, surface tension and dynamic laser light scattering (DLS). It was found that with increasing PFMA block length, water and oil repellency decreased, the ratio of F/C increased with increasing film depth, and the degree of ordered packing of the perfluoroalkyl side chains at the surface decreased. When the number of PFMA block units reached 10, PMMA segments were detected at the copolymer surface, which was attributed to the PFMA block length affecting molecular aggregation structure of the copolymer in the solution and the interfacial structure at the air/liquid interface, which in turn affects surface structure formation during solution solidification. The results suggest that copolymer solution properties play an important role in structure formation on the solid surface. Supported by the National Natural Science Foundation of China (Grant Nos. 50573069 and 20704038) and Program for Changjiang Scholars and Innovative Research Team in University (Grant No.IRT 0654)     

四硫富瓦烯─多酸分子杂化材料化学研究进展

综述了一类有机－无机超分子组装体系四硫富瓦烯─多酸分子杂化材料近年来的研究进展。分述了Ｋｅｇｇｉｎ型杂多阴离子、Ｄａｗｓｏｎ－Ｗｅｌｓ型杂多阴离子、Ｌｉｎｄｇｕｉｓｔ型同多阴离子以及含有顺磁性过渡金属原子的多阴离子的四硫富瓦烯和双乙基四硫富瓦烯的荷移盐和游离基离子盐的结构特征与导电性质,有机与无机亚单元间的磁交换性质介绍了杂多阴离子的低聚四硫富瓦烯盐的新进展     

聚N,N-二乙基丙烯酰胺温敏水凝胶的药物释放研究

在合成聚Ｎ,Ｎ－二乙基丙烯酰胺温敏水凝胶的基础上研究了该水凝胶在ＬＣＳＴ附近对药物的释放（以氟哌酸为主）。温度与交联度的变化对药物的释放皆有明显的影响。通过对释放曲线进行计算机模拟得到释放液浓度的经验公式,并从理论上初步解释了公式中各参数的物理意义。作出了理论近似计算得到的表观扩散系数的变化曲线,其在ＬＣＳＴ附近各温度的变化趋势符合预测     

10TeV宇宙线的太阳阴影与太阳活动的关联

利用1990年6月至1993年10月间采集的数据,西藏空气簇射阵列(海拔高度4300m)以5.7σ、7.1σ的显著性观测到了10TeV宇宙线的太阳阴影和月亮阴影;研究发现,行星际磁场效应使太阳阴影偏向西0.62°,南0.22°:仔细研究了太阳阴影与太阳活动及其不对称性的关联,对太阳阴影位置的偏转发其变化行为给出了新的定性解释.     

基体预注氮改善PECVD TiN镀层的耐磨性能

作者考察了基体离子注氮预处理对等离子体增强化学气相沉积(PECVD)TiN镀层结合强度及耐磨性的影响。结果表明,基体经离子注氮预处理的PECVD TiN镀层之结合强度比基体未经离子注氮预处理的高,油润滑条件下的耐磨寿命也比后者的长,干摩擦条件下的耐磨性更比后者的好。X-射线衍射及电子探针分析发现,基体经离子注氮预处理后镀层的TiN(200)峰宽化,镀层与基体的界面变宽。