固定pH敏感微凝胶和刚果红复合凝胶膜的传感性能与应用

以化学交联的聚乙烯醇(PVA)凝胶为基质,固定由沉淀聚合法制备的聚(丙烯酰胺-co-甲基丙烯酸)[P(AM-co-MAA)]微凝胶和刚果红,构筑了对p H有光学响应性的新型复合凝胶膜。采用连接有紫外-可见分光光度计的测试系统对复合凝胶膜的传感性能进行了研究,并考察了复合凝胶膜的响应时间和稳定性。结果表明,P(AM-co-MAA)微凝胶和刚果红对光吸收性能有明显的协同增效作用,复合凝胶膜的p H响应范围为4.1~0.5,响应时间小于100 s,显示出比固定单一p H敏感物更优越的性能。     

尿素/乙醇胺复配增塑聚乙烯醇性能的研究

采用尿素/乙醇胺为复合增塑剂,利用流延法制备了增塑改性的PVA膜.通过FTIR法研究了尿素/乙醇胺复合体系与PVA的相互作用,采用XRD、DSC考察了增塑改性PVA膜的结晶性能和热性能.研究结果表明,乙醇胺作为尿素的良溶剂,能有效抑制尿素从PVA基体中析出.由尿素、乙醇胺组成的复合增塑剂能破坏PVA分子中的氢键作用、降低PVA的结晶度和熔点,对PVA的增塑作用显著.增塑改性后的PVA膜在水中的溶胀率(DS)下降,溶失率(S)增加.力学性能测试表明增塑改性后的PVA膜拉伸强度(TS)降低,断裂伸长率(E%)提高.含30phr尿素/乙醇胺的PVA膜的拉伸强度、断裂伸长率分别为23.89MPa和542.88%.     

层状纳米纤维素膜/PVA复合水凝胶的制备与力学性能研究

采用叠层复合与物理相分离的方法制备了层状纳米细菌纤维素(BC)膜/聚乙烯醇( PVA)复合水凝胶.研究了聚乙烯醇的质量百分数、BC膜的复合层数以及制备条件对复合水凝胶力学性能的影响;通过扫描电镜( SEM)观察比较了复合水凝胶中BC膜层与PVA界面结合情况.结果表明,复合水凝胶的力学性能与PVA的质量百分数和BC膜含水...     

基于聚乙烯醇/金纳米棒复合凝胶膜的Hg~(2+)传感器构建及应用

利用种子生长法制备金纳米棒,将其分散于聚乙烯醇溶液中,以戊二醛为交联剂,制备了对Hg2+有光学响应性的化学交联聚乙烯醇/金纳米棒(PVA/GNRs)复合凝胶膜。利用紫外-可见光谱法表征了该复合凝胶膜对Hg2+的传感性能。结果表明,在还原剂抗坏血酸的辅助下,PVA/GNRs凝胶对Hg2+有良好的光学响应和选择性,测量线性范围为0.1~3.0μmol/L,相关系数为0.997,响应时间为5 min。以PVA/GNRs复合凝胶膜构建的光学传感器具有制备方法简便、稳定性高等优点,可用于水样中微量Hg2+的检测。     

竹纤维复合亲水膜的制备及性能研究

以碱处理的改性竹纤维(BF)、乳酸(LA)为反应原料,制备PLA-g-BF接枝物。PLA-g-BF接枝物分别与壳聚糖(CS)、聚乙烯醇(PVA)为原料的体系进行复合,制备竹纤维复合亲水膜,探究了CS(PVA)溶液质量浓度和PLA-g-BF/CS(PVA)溶液质量配比对所制备的竹纤维复合亲水膜的结构、拉伸强度、形貌、亲水性、附着力及降解性的影响。结果表明:CS溶液质量浓度为1/40(g/mL),接枝物与CS溶液质量配比为2∶40时,膜的拉伸强度为4.93MPa,接触角为72.9°,硬度为2H,基本不降解;PVA溶液质量分数为7%,接枝物与PVA溶液质量配比为2∶40时,膜的拉伸强度为17.2MPa,接触角为53.2°,硬度为5H,6天内全部降解。     

聚乙烯醇(PVA)/壳聚糖(CS)合金膜的醇-水渗透汽化分离性能研究

在表征了PVA/CS共混体系相容性的基础上,本文报导MeOH-H_2O,EtOH-H_2O和i-PrOH-H_2O体系在PVA,CS及其合金膜中的渗透汽化行为。讨论了温度、料液浓度、合金膜的组成对分离性质的影响。从膜的分子和聚集态结构出发对相关的渗透行为进行了解释。对于PVA、CS及其合金膜来说,膜内自由体积大小看来是影响分离性能的主要因素,小分子在膜中的渗透性质主要是由扩散控制的。     

PVA/PEG/Mg(OH)_2复合材料体系的非等温结晶行为

采用熔融共混法,以聚乙二醇(PEG)为增塑剂、Mg(OH)2为稳定剂制备了聚乙烯醇(PVA)/PEG/Mg(OH)2复合材料。利用差示扫描量热仪(DSC)考察了PVA/PEG/Mg(OH)2复合体系中PVA的非等温结晶行为。结果表明:在熔融过程中PEG与PVA大分子形成的分子间氢键,破坏了PVA分子内或分子间的氢键,改善了PVA的热塑性能,使研究其熔融结晶行为成为可能。     

AgBr的尺寸及含量对PVA为粘合剂的光敏热成像材料的光敏性的影响

本文以水溶性聚乙烯醇(PVA)为粘合剂,采用异位法合成不同尺寸的立方体AgBr乳剂为光敏元,考察了以硬脂酸银/溴化银为主体的光敏热成像材料体系在可见光区的光敏性与立方体AgBr颗粒尺寸以及含量之间的关系.实验结果表明:在体系中AgBr含银量确定的条件下,AgBr颗粒尺寸在100—200nm范围内,体系的光敏性最大;AgBr与AgSt的银量比在40%左右,体系的光敏性出现最大值;而AgBr乳剂中本身存在的少量明胶对体系的光敏性影响很小.     

耗散粒子动力学模拟Nafion膜和PVA/Nafion共混膜的介观结构

采用耗散粒子动力学模拟方法研究了水化Nafion膜和水化聚乙烯醇(PVA)/Nafion共混膜的微结构.模拟结果表明水化Nafion膜和水化PVA/Nafion共混膜均能形成相分离的微结构.在水化Nafion膜中,水与磺酸根混合形成管状的水团簇.随着膜内水含量增多,管状水团簇的尺寸逐渐变大并在膜内形成连续的水通道.在水化PVA/Nafion共混膜中,PVA、水、磺酸根混合形成亲水性区域.共混膜中PVA的质量分数和水含量共同影响膜的微结构.当膜中PVA质量分数较低时,PVA主要分布在Nafion的磺酸根基团周围;PVA质量分数升高后,PVA会在膜内单独成一相.当膜中的水含量相对较低时,水分子会溶解于PVA中,此时膜内不存在单独的水团簇;膜中的水含量增多后,膜内会形成接近于球形的水团簇.本文工作可为直接甲醇燃料电池用的PVA改性Nafion膜的开发提供参考.     

十二烷基硫酸钠对聚乙烯醇亚浓水溶液流变行为的影响

表面活性剂会影响聚乙烯醇(PVA)分子间及分子内氢键形成,进而改变其水溶液的流变响应.本文在确定十二烷基硫酸钠(SDS)在PVA亚浓水溶液中的临界聚集浓度(CAC)和临界胶束浓度(CMCP)基础上,考察了SDS对PVA亚浓溶液(10 wt%)流变行为的影响.研究发现,不同浓度SDScsur对PVA水溶液稳态流变行为的影响差异较大:(1)当csur CMCP,随着csur增加,胶束起物理交联点作用,ηa增大,复合溶液的动态储能模量亦显著增大.加入SDS后,PVA体系内结合水的数目降低,但当csur> CMC后,结合水的数目几乎不变,黏流活化能也表现出相近的变化规律.与稀溶液相比,SDS对PVA亚浓溶液的降黏幅度较大.     

Preparation and Characterization of Ag2 O/Organicsilicone Self-assemblied Composite Film

The composite film of nanometer AgO2/silane coupling reagent aminopropyltriethoxy-silane (CH3O)3Si(CH2)3NH2was prepared on single-crystal silicon by the self-assembly of silane on the hydroxylated substrate followed with the deposition of nanometer AgO2 on the silane SAMs from an aqueous Ag2O gel. The resultant composite film was characterized by means of X-ray photoelectron spectroscopy (XPS) and atomic force microscopy (AFM). The contact angles of distilled water on the silane SAMs and the composite film were measured to compare the surface states. The experiment shows that the nanometer Ag2O can be easily incorporated in the silane SAMs and lead to changed surface state of the composite film. Nanometer Ag2O crystallites in a size of about 20 nm distribute quite uniformly in the composite film. It was anticipated that the composite film might find application to the protection of single-crystal Si substrate in MEMS devices and also propose a novel single electron device structure based on nanoscale Ag2O colloidal particles.     

Electrochemical Characterization of Poly(N‐acetylaniline)/Nafion Composite Film in Neutral and Basic Aqueous Solutions

Electrochemical synthesis of poly(N‐acetylaniline) (PNAANI)/Nafion composite film was carried out by cyclic voltammetry (CV). Its surface morphology, which was evaluated by scanning electron microscopy (SEM), revealed that PNAANI was dispersed into the Nafion film uniformly. X‐ray photoelectron spectrum (XPS) of the composite film was also examined. The electroactivity of the composite film was high in neutral and basic solutions, and the stability of PNAANI/Nafion film in neutral and basic solutions was excellent.     

纳米银-磷酸锆复合膜修饰电极的制备和电化学

合成了新型纳米银-磷酸锆复合材料并用其修饰玻碳电极,用循环伏安法对修饰电极进行电化学研究.结果表明,此复合膜保持了银的纳米尺寸的微粒性质和磷酸锆对碱性染料的电位调制能力.复合膜中的纳米银提高了磷酸锆对中性红的吸附能力,增强了中性红的氧化还原反应活性.复合膜修饰电极表现出更灵敏的电化学响应.复合膜比单纯的磷酸锆膜表现出更好的机械强度,用其制备的修饰电极表现出更好的稳定性.     

硒/氧化石墨烯/二氧化钛复合薄膜的制备及光电转换性质

将氧化石墨烯(GO)掺入钛酸溶胶中,以导电玻璃(ITO)为基底,经浸渍-涂覆-煅烧得到GO/TiO2复合薄膜;采用电沉积技术在GO/TiO2薄膜表面沉积Se纳米微粒,得到Se/GO/TiO2复合薄膜;利用扫描电子显微镜和X射线衍射仪分析了复合薄膜的形貌和晶体结构,采用紫外可见光谱仪测定了其光谱学性质,利用光电转换实验测定了其光电转换性质.结果表明,所制备的Se/GO/TiO2复合薄膜各组分分布均匀,具有锐钛矿相结构的TiO2颗粒粒径为20nm,与TiO2结合的GO具有分散片层结构,薄膜中的Se颗粒粒径为60～80nm.与此同时,在Se和GO的共同作用下,Se/GO/TiO2复合薄膜对可见光有很好的光电转换效应.     

TiO_2聚苯胺复合膜的光电化学

利用电化学方法制备了TiO2 聚苯胺 (PANI)复合膜 .该膜具有比TiO2 或PANI膜更宽的吸收谱区 ,并且不同于利用聚苯胺光敏化的TiO2 膜 ,表现为两者复合材料膜的性质 .扫描电镜图表明 ,TiO2 微粒不完全覆盖着PANI膜 .根据TiO2 微粒光电流谱带的阈值能可得复盖在部分氧化态聚苯胺膜上的TiO2 微粒的禁带宽度为 3.0eV .部分氧化态聚苯胺膜的光电流谱遵循Fowler定律 ( 1/2 ～hυ成线性 ) .通过Fowler图得出部分氧化态聚苯胺的绝缘母体禁带宽度为 3.33eV ,并证实该绝缘母体为还原态聚苯胺 .从Mott Schottky图得到在 0 .0 5mol/LK3Fe(CN) 6 /K4 Fe(CN) 6 溶液中 (pH =8.52 )部分氧化态聚苯胺的平带电位为 0 .13V ,掺杂浓度为 5.3× 10 18cm- 3;TiO2 PANI复合膜的平带电位为 - 0 .6 5V ,掺杂浓度为 9.1× 10 19cm- 3.解释了TiO2 PANI复合膜的光电化学过程并描绘出其能带图 .利用TiO2 PANI复合膜能够有效地光降解苯酚溶液 .     

Interfacial Interaction of Polymer/Liquid Crystal Molecules and Electrooptical Properties of their Composite Systems

Polymer/liquid crystal composite films were prepared from a solution of polymer and nematic liquid crystal (LC) by a solvent casting method. The phase-separated structure of the composite film was controlled by the solvent evaporation rate. The light-scattering profile of a poly(diisopropyl fumarate)/LC: 40/60 w/w solution during solvent evaporation exhibited a periodic structure, indicating that the phase-separated structure was formed by spinodal decomposition. The aggregation structure of the composite film was investigated with a scanning electron microscope (SEM). SEM observation of the composite film suggested the presence of periodicity and dual connectivity of polymer and LC phases. The faster the solvent was evaporated, the smaller the LC channel (domain) size in the composite film. The composite film, composed of poly(methyl methacrylate) (PMMA) and a nematic LC (E44) with a positive dielectric anisotropy, exhibited remarkable and reversible light-scattering-light-transmission switching, under the modulation of an ac electric field. The light-scattering state was dependent on such optical heterogeneities as spatial distribution of the nematic directors and/or mismatching in the refractive indices of the components. The electrooptical behavior of the composite film was strongly dependent on the LC channel (domain) size in the composite film. The transmittance increased and the rise and decay response times (τ_R and τ_D), decreased and increased, respectively, with an increase in the size of the LC channel (domain).

The electrooptical switching properties for the polymer/LC composite film should be influenced by miscibility between the polymer and the LC phases. The miscibility between both phases was evaluated from a distribution of relaxation time for interfacial polarization. The anchoring effect was also investigated by measuring the nonlinearity of the dielectric constant for the composite system.     

Direct electrochemistry and electrocatalysis of horseradish peroxidase immobilized in sol–gel-derived tin oxide/gelatin composite films

Horseradish peroxidase (HRP) was immobilized into a new type of sol–gel-derived nano-sized tin oxide/gelatin composite film (SnO₂ composite film) using a sol–gel film/enzyme/sol–gel film “sandwich” configuration. Direct electrochemistry and electrocatalysis of HRP incorporated into the composite films were investigated. HRP/SnO₂ composite film exhibited a pair of stable and quasi-reversible cyclic voltammetric peaks for the HRP Fe(III)/HRP Fe(II) redox couple with a formal potential of about −0.25 V (vs. SCE) in a pH 6.0 phosphate buffer solution. The electron transfer between the enzyme and the underlying electrode was greatly enhanced in the microenvironment with nano-SnO₂ particles and nanoporous structures. Morphologies and microstructures of the composite films and HRP/composite films were characterized with TEM, AFM. Electrochemical impedance spectroscopy (EIS) was also used to feature the HRP incorporated into composite films. FTIR and UV–Vis spectroscopy demonstrated that HRP in the composite film could retain its native secondary structure. With the advantages of organic–inorganic hybrid materials, the HRP/SnO₂ composite film modified electrode displayed good stability and electrocatalytic activity to the reduction of H₂O₂, The apparent Michaelis-Menten constant was estimated to be 0.345 mM, indicating a high affinity of HRP entrapped into the composite film toward H₂O₂.     

Fabrication of tri-polymers composite film with high cyclic stability and rapid degradation for cardiac tissue engineering

In this communication, biodegradable and highly elastic silk fibroin/poly(lactide-co-ε-caprolactone)/polyethylene oxide (SF/PLCL/PEO) tri-polymers composite film was fabricated by sol–gel casting technology. The tri-polymers composite film exhibited a high cycle performance and rapid degradation rate by regulating the content of blending of the three polymer contents. The viability of cardiomyocyte cells was demonstrated for both SF/PLCL and SF/PLCL/PEO composite films after 1 day of culture, although the tri-polymers composite film demonstrated superior cell growth, attachment and spreading after culturing for 7 days. Study findings support the potential application of this biocompatible tri-polymers composite film as a heart patch substitute with multi-functionalities.     

SPEEK/PVA-AgNPs复合膜的制备与表征

首先,以磺化聚醚醚酮(SPEEK)为光敏自由基载体,以聚乙烯醇(PVA)为分散稳定剂,制备了具有光生自由基功能的SPEEK/PVA高分子膜;然后,通过在SPEEK/PVA膜上紫外光诱导Ag+还原生成纳米银颗粒(AgNPs),从而得到SPEEK/PVA-AgNPs复合膜。采用紫外可见分光光度计(UV-Vis)、扫描电镜(SEM)、能谱仪(EDS)、X射线光电子能谱分析(XPS)及傅里叶变换红外光谱(FT-IR)等手段对SPEEK/PVA-AgNPs材料进行了表征。结果显示:生成的银颗粒为纳米级,较均匀地分布在SPEEK/PVA高分子膜表面,SPEEK/PVA-AgNPs复合膜整体呈现棕色;形成的银纳米颗粒具有较完整的晶型,且价态分析显示其为单质。     

Growth and photoluminescence characterization of highly oriented CuI/beta-cyclodextrin hybrid composite film

A highly (111) oriented CuI/beta-cyclodextrin inorganic/organic composite film on glass substrates was deposited from a dispersion of CuI and beta-cyclodextrin in a mixture of acetonitrile and dimethylformamide (DMF) solvents, in which DMF plays an important role in the orientation of CuI film. The composite film exhibits obviously improved band gap photoluminescence compared with that of the pure CuI film due to the passivation of iodine-related defect sites by beta-cyclodextrin matrix. This result indicates that the optical properties of CuI film can be easily adjusted by the formation of composite film with proper ligand agents.