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Dynamic behavior of polymer surface and the time dependence of contact angle

science china Chemistry 2005年第6期48卷 553-559页

作者： WANG Xinping1, CHEN Zhifang1 & SHEN Zhiquan2.1. Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry, department of Applied Chemistry, zhejiang Institute of {2. and Technology, hangzhou 310033, china 2. department of polymer science and engineering, zhejiang university, hangzhou 310027, china 1. department of Applied Chemistry Zhejiang Institute of Science and Technology Key Laboratory of Advanced Textile Materials and Manufacturing Technology of Education Ministry 310033 Hangzhou China 2. department of polymer science and engineering Zhejiang University 310027 Hangzhou China

Time-dependent contact angles were measured by depositing sessile drops of wa-ter on the polymer surfaces and monitoring the drop shape as a function of time. It was found that contact angles decreased sharply with contact time and the equilibrium contact angle was finally attained after a certain time. Values of starting (θ s) and equilibrium contact angles (θ e) obtained by the sessile drop method depend on polymer properties. The Wilhelmy plate technique was used to measure advancing and receding contact angles. The variations of starting (θ s) and equilibrium contact angles (θ e), advancing (θ a) and receding contact angles (θ r) have been studied on the oxidized surface of polymers containing polybutadiene block to explore the cause of time-dependence in contact angle measurement and the meaning of θ s and θ e. The results showed the linear relationships between starting (θ s) and advancing contact angles (θ a), the equilibrium (θ e) and receding contact angles (θ r). The similar relationship was also established between the contact angle hysteresis (θ a?θ r) and differences (θ s ?θ e) in starting contact angles and equilibrium contact angles. Therefore, time-dependence in contact angle measurement was mainly attributed to the surface reconstruction when water drops were deposited on polymer surfaces. The starting contact angle was contributed by the hydrophobic component on polymer surface and the equilibrium contact angle mainly by the hydrophilic component of polymer. These results not only demonstrated the interdependency between two contact angle measurements, the sessile drop method and the Wilhelmy plate technique, but also provided the experimental evidence to explain the cause of time-dependent contact angle. This may also provide a new method to study dynamic behavior of polymer surface.

关键词： contact angle, surface dynamic behavior, polymer surface, dynamic contact angle, time-dependence.

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Thermosensitive self-assembly behaviors of novel amphi- philic polyphosphazenes

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science Bulletin 2005年第14期 47-49页

作者： QIU Liyan1, ZHANG Jianxiang1,2. JIN Yi1 & ZHU Kangjie2.1. College of Pharmaceutical sciences, zhejiang university, {2. 310031, china 2. department of polymer science and engineering, zhejiang university, hangzhou 310027, china

A series of amphiphilic thermosensitive poly- phosphazenes (PNIPAm-g-PPP) bearing N-isopropylacryla- mide oligomers (oligo-PNIPAm) and glycine ethyl groups (GlyEt) as co-substituents have been synthesized via polymer substitute reaction. UV-visible spectra indicated that the aqueous solution of PNIPAm-g-PPP exhibited the lower critical solution temperature (LCST). Furthermore, the LCST was seriously influenced by the substitution ratios of PNIPAm to GlyEt in the copolymer. The more GlyEt the copolymer contained, the lower LCST it had. The critical association concentration (cac) of copolymers was deter- mined by fluorescence probe method. It was found that cac was decreased with increasing GlyEt content of polyphos- phazene. Also the formation of self-assembled micelles or nano-particles was confirmed by TEM.

关键词： polyphosphazene thermosensitivity lower critical solu- tion temperature micelle.

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[(NaC_9H_6)Me_2.C_5H_4]_2.m(Ⅱ)(THF)_2.合成及其催化MMA聚合的研究

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中国稀土学报 2002年第Z3期20卷 26-29页

作者：龚新强齐民华沈琪沈之荃苏州大学化学化工系江苏苏州215006 浙江大学高分子科学与工程系浙江杭州310027

以茚基锂与6,6 二甲基富瓦烯的环外双键加成反应合成了一个新型取代茂基锂[(C9H7)Me2.]C5H4Li(1,其中C5H4代表一取代环戊二烯基),(1)与无水三氯化钐按2.1摩尔比反应后,再用与稀土钐的摩尔比为3∶1的钠砂处理,合成了二价钐的三核双金属... 详细信息

以茚基锂与6,6 二甲基富瓦烯的环外双键加成反应合成了一个新型取代茂基锂[(C9H7)Me2.]C5H4Li(1,其中C5H4代表一取代环戊二烯基),(1)与无水三氯化钐按2.1摩尔比反应后,再用与稀土钐的摩尔比为3∶1的钠砂处理,合成了二价钐的三核双金属配合物[(NaC9H6)Me2.C5H4]2.m(Ⅱ)(THF)2.2.其中C9H6代表茚基)。该配合物经元素分析和红外光谱表征,并发现(2.能高活性地催化甲基丙烯酸甲酯聚合,得到等规含量较高的聚甲基丙烯酸甲酯。

关键词：稀土合成钠钐双金属稀土配合物聚合甲基丙烯酸甲酯

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A NOVEL RESISTIVE HUMIDITY SENSOR BASED ON SODIUM POLYSTYRENESULFONATE/TiO_2.NANOCOMPOSITES

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Chinese Journal of polymer science 2002年第3期20卷 237-241页

作者： Yang Li Mu-jie Yang Yong She department of polymer {2. and engineering zhejiang university, hangzhou 310027 china zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

A resistive humidity sensor was prepared based on sodium polystyrenesulfonate (NaPSS)/TiO2.nanocomposites, and its electrical response to humidity was examined. The sensor exhibits better linearity, smaller hysteresis (2.s; desorption: less than 2. s) in comparison with sensor composed of NaPSS. The effect of concentration of NaPSS and TiO2.on humidity response of sensors was discussed.

关键词： humidity sensor nanocomposites TiO2 sodium polystyrenesulfonate

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GRAFTING OF HYDROPHILIC MONOMERS ONTO POLYURETHANE MEMBRANES BY SOLUTION OR PRE-ABSORBING METHODS FOR ACCELERATION OF CELL COMPATIBILITY

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Chinese Journal of polymer science 2001年第5期19卷 493-498页

作者： Chang-you Gao Jian-jun Guan Jia-cong Shen department of polymer {2. and engineering zhejiang university hangzhou 310027, china zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

Two grafting methods, i.e. solution grafting and pre-adsorbing, are introduced to covalently immobilizehydrophilic polymers on segmented polyurethane (SPU) to modify its hydrophilicity and to improve its cell *** grafting results in higher degree of grafting and rougher surface morphology. Cell culture evaluation demonstratesthat the modified membranes thus obtained are disadvantageous to the endothelial cell (ECs) growth probably because thehydrophilic groups on the surface are over-crowded. However, pre-absorbing grafting generates lower degree of grafting,which is detected and confirmed by ATR-FTIR spectra and water conted angle. Scanning electron microscopic (SEM)measurement shows that the latter method produces a plane and smooth morphology, which is similar to the SPU controlsample controlled. When grafting with lower monomer concentration, ECs could grow on SPU-g-PHEA [poly(2.hydroxyethyl acrylate)], SPU-g-PAAm (polyacrylamide), SPU-g-PDMA [poly(2.(dimethylamino)ethyl methacrylate)] orquatemized SPU-g-PDMA surface with elongated cell shapes. Hence, the cell compatibility of SPU is improved and a usefulmethod to construct a cell compatible layer on the polymer surface has been developed.

关键词： segmented polyurethane cell compatibility surface grafting endothelial cell

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RANDOM COpolymer OF PROPYLENE OXIDE AND ETHYLENE OXIDE PREPARED BY DOUBLE METAL CYANIDE COMPLEX CATALYST

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Chinese Journal of polymer science 2002年第5期20卷 453-459页

作者： Yi-jun Huang Guo-rong Qi Guan-xi Chen department of polymer {2. and engineering, zhejiang university hangzhou 310027,china zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

Copolymerization of propylene oxide (PO) and ethylene oxide (EO) using double metal cyanide (DMC) complex as the catalyst was carried out. The structure of random copolymers was confirmed by C-13-NMR and IR spectra. H-1-NMR analysis shows that the EO content in the copolymer is the same as that in the initial monomer feed. Moderate molecular weight copolymers with various EO content were obtained and their values of molecular weight distribution (MWD) fell in the range of 1.2.-1.55. It was found that the molecular weight of copolymers is controlled by the mass ratio of EO+PO to initiator moles used, The reaction rate as well as polymer yield decrease with increasing EO content in the feed composition.

关键词： propylene oxide ethylene oxide double metal cyanide complex

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SOME THERMODYNAMIC PROPERTIES OF Pd-In ALLOYS

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Acta Metallurgica Sinica(English Letters) 1997年第4期10卷 311-317页

作者： YL. Chen(department of Materials science and {2., zhejiang university, hangzhou 310027, china) zhejiang Univ Hangzhou China

Some thermodynamic parnmeters of Pd-In alloys with 2.to 70 at. H indium have been determined in the temperuture range 800 to 1000℃ from e.m.f measurements ongalvanic cells with an onsen-cotzducting solid electrolyte. Heats of tnising calculated hem the activities are in excellent agreement with calorimetric data. The relative partial excess hee enengy of indiurn assumes unnsually larpe negative values ap to-174kJ/mol for Pd-rich alloys. Two efficts are discussed to account for the non-idealproperties: The rise Of Fermi enerpy as the valence electron8 of indium enter the 4dand 5sP bands of the alloy and the lattice distortion brought about by the differentmolar volumes of the cofnponents. The rise of the Fermi enerpy, as determlned fromthe activity data, indicates a strict adherence of the alloys to the rigid band model.

关键词： galvanic cell activity data Fermi energy,lattice distortion rigid band model

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HYDRIDING INFLUENCE OF INDIUM ON Pd-In ALLOYS

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中国有色金属学会会刊：英文版 1996年第3期6卷 63-67页

作者： Chen Yanglin(department of Materials science and {2., zhejiang university, hangzhou 310027) zhejiang UNIV DEPT MAT SCI & ENGNHANGZHOU 310027PEOPLES R CHINA

ＨＹＤＲＩＤＩＮＧＩＮＦＬＵＥＮＣＥＯＦＩＮＤＩＵＭＯＮＰｄ－ＩｎＡＬＬＯＹＳ￥ＣｈｅｎＹａｎｇｌｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ，ＺｈｅｊｉａｎｇＵｎｉｖｅ... 详细信息

ＨＹＤＲＩＤＩＮＧＩＮＦＬＵＥＮＣＥＯＦＩＮＤＩＵＭＯＮＰｄ－ＩｎＡＬＬＯＹＳ￥ＣｈｅｎＹａｎｇｌｉｎ（ＤｅｐａｒｔｍｅｎｔｏｆＭａｔｅｒｉａｌｓＳｃｉｅｎｃｅａｎｄＥｎｇｉｎｅｅｒｉｎｇ，ＺｈｅｊｉａｎｇＵｎｉｖｅｒｓｉｔｙ，Ｈａｎｇｚｈｏｕ３１０...

关键词： hydriding valence electrons lattice dilatation Fermi energy

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STEREOCHEMICAL CONTROL IN PROPYLENE polymerIZATION CATALYZED BY UNBRIDGED METALLOCENE CATALYSTS

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Chinese Journal of polymer science 2001年第4期19卷 407-413页

作者： Yin-bang Zhu Zhi-qiang Fan Tariq Yasin Lin-xian Feng department of polymer {2. and engineering zhejiang university hangzhou 310027, china zhejiang Univ Dept Polymer Sci & Engn Hangzhou 310027 Peoples R China

Two unbridged metallocene catalysts, bis(2.4,7-trimethylindenyl)zirconium dichloride (met-I) and bis(2.4,6-trimethylindenyl)zirconium dichloride (met-II), which are different in the position of substituents on the six-membered ring of the indenyl ligands were synthesized. The effect of substituents in the two metallocenes on the propylene polymerization was studied in the presence of methylaluminoxane (MAO) and triisobutylaluminium (TIBA). From the analysis of microstructure determined by C-13-NMR, it was demonstrated that the polymers produced by met-II have higher [mmmm] isotactic sequences than that of met-I. Using a mechanism based on model statistical analysis, it was found that chain-end model was dominant for met-I. However, met-II obeys the concurrent two-sites model during polymerization, which can be attributed to the existence of 'racemic-like' conformer in its system.

关键词： unbridged metallocene propylene polymerization elastomeric polypropylene stereochemical mechanism

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polymerIZATION OF γ-STEARYL-α,l-GLUTAMATE N-CARBOXYANHYDRIDE USING RARE EARTH COORDINATION CATALYSTS

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Chinese Journal of polymer science 2000年第4期18卷 369-372页

作者： Xiao-ping Hu Jian Wu Zhi-kang Xu Lin-xian Feng Institute of polymer science,{2., hangzhou 310027, china department of Chemistry,{2., hangzhou 310027, china zhejiang Univ Dept Chem Hangzhou 310027 Peoples R China zhejiang Univ Inst Polymer Sci Hangzhou 310027 Peoples R China

A rare earth coordination system was first investigated as a new type of catalyst for the ring-openingpolymerization of α-amino acid N-carboxyanhydrides (NCAs). The results for the polymerization of γ-stearyl-α,L-glutamate(SLG) NCA using neodymium acetylacetonate (Nd(acac)_3)- or neodymium tris(2.ethylhexylphosphonate) (Nd(P_(2.4))_3)-triethylaluminum-water as catalysts were compared with those using conventional catalysts. It was found that the helicalpoly(γ-stearyl-L-glutamate) with high molecular weight as well as narrow molecular weight distribution can be obtained inthe presence of Nd(acac)_3/AlEt_3-1/2._2.. The polymer obtained was characterized by IR and NMR spectroscopy.

关键词： Rare earth coordination catalyst Ring-opening polymerization Polypeptide Poly(γ-stearyl-α,L-glutamate)

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