聚合物熔体膜在基体表面的润湿和铺展行为

聚合物熔体膜在基体表面上的润湿和铺展行为受铺展系数和Hamaker常数影响。对于不能在基体表面上铺展的聚合物膜,当处于其玻璃化温度以上时,聚合物熔体膜将破裂,出现非连续区域。随着体系处于聚合物玻璃化温度以上时间的延长,非连续部分尺寸不断增长,增长速率与表面张力、聚合物粘度、聚合物液滴在基体表面的平衡接触角等因素有关,平衡后聚合物以液滴的形式在基体表面稳定存在。将带功能端基聚合物加入不能在基体表面上铺展的聚合物中,通过修饰聚合物与基体界面或改变聚合物熔体膜的表面张力,可以使原来不能在基体表面铺展的聚合物保持稳定。本文综述了聚合物熔体膜的铺展和润湿动力学研究进展,并归纳了使聚合物熔体膜稳定的方法。     

聚甲基丙烯酸甲酯单分子膜的原子力学显微镜研究

报道了利用原子力显微镜（ＡＦＭ）技术对聚甲基丙烯酸甲酯（ＰＭＭＡ）单分子膜进行分子结构水平的观察研究．由ＡＰＭ图像中得到的ＰＭＭＡ单体所占面积与用π－Ａ曲线中换算出液面上ＰＭＭＡＬａｕｇｍｕｉｒ膜中单体的面积符合得很好．从ＡＦＭ图像中可见ＰＭＭＡＬＢ膜中ＰＭＭＡ的线型碳链是与档板（ｂａｒｒｉｅｒ）平行的紧密排列，与ＬＢ提膜方向相垂直．并由此对ＰＭＭＡＬＢ膜的形成过程进行分析．此外，还观察到了在Ｓｉ基底上ＰＭＭＡ直链的卷绕伸直排列形态，初步分析了其形成原因．     

用含偶氮基的聚苯乙烯大分子引发剂合成两亲性嵌段共聚物

采用含偶氮基的聚苯乙烯预聚物（ＰＳ ＡＣＰＣ）作为引发剂，合成了苯乙烯（Ｓｔ）分别与甲基丙烯酸（ＭＡＡ）、甲基丙烯酸（β 羟丙酯）（ＨＰＭＡ）的嵌段共聚物，考察了ＰＳ ＡＣＰＣ引发第二单体的聚合反应行为，以及影响第二单体转化率和均聚物含量、共聚物组成的因素．用溶解性、凝胶渗透色谱（ＧＰＣ）、红外光谱（ＩＲ）、核磁共振（ＮＭＲ）、动态接触角（ＤＣＡ）等表征了嵌段共聚物．     

原子力显微镜研究APS化单晶硅衬底及单层MD膜表面

原子力显微镜研究ＡＰＳ化单晶硅衬底及单层ＭＤ膜表面张希，高芒来，王力彦，沈家骢（吉林大学化学系，长春，１３００２３）关键词原子力显微镜，ＡＰＳ修饰表面，分子沉积膜以静电相互作用为成膜推动力的各种功能体系分子沉积（ＭＤ）超薄膜已有报道［１￣４］．对ＭＤ...     

纳米结构表面上冷凝液滴的生长模式及部分润湿液滴的形成机制

分析并计算了纳米结构表面上冷凝液滴按照不同途径长大的过程中液滴能量的增加速率, 并以能量增加最小为判据来确定液滴的生长途径. 结果表明, 纳米结构内形成的冷凝液斑在初期按接触角(CA)增加的模式生长时, 其能量增加速率远低于其它模式, 于是, 初始液斑先按增大接触角、并保持底面积不变的模式生长, 直至液滴达到前进角状态. 此后, 沿接触角增加的模式长大所导致的能量增加速率开始远高于其它生长模式, 于是液滴三相线开始移动, 底面积开始增加, 但接触角保持不变. 液滴所增加的底面积可以呈润湿或复合两种状态, 分别形成Wenzel 液滴及部分润湿液滴, 前者的表观接触角一般小于160°, 而后者则明显大于160°. 液滴的生长模式及其润湿状态均与纳米结构参数密切相关, 仅当纳米柱具有一定高度、且间距较小时, 冷凝液滴才能呈现部分润湿状态. 最后, 本模型对纳米结构表面上冷凝液滴润湿状态的计算结果与绝大部分实测结果相一致, 准确率达到91.9%, 明显高于已有公式的计算准确率.     

聚甲基丙烯酸甲酯Langmuir—Blodgett复合膜及其在光电导体中…

制备了聚甲基丙烯酸甲酯（ＰＭＭＡ）ＬＢ复合膜，将其作为阻挡层首次应用于机能分离型光电导体领域。从π－Ａ曲线发现ＰＭＭＡ单分子膜具有表面压力的各向异性和松弛特性。ＴＥＭ照片显示，ＰＭＭＡ分子链在复合膜中有序排列。转移比、ＵＶ和ＸＰＳ研究表明，复合膜沉积均匀。以ＰＭＭＡ－ＬＢ复合膜作为阻挡层的光电导体表面充电电位Ｖ０＝１５１８Ｖ，光照１ｓ后的光衰百分率△Ｖ１ｓ＝５０．１６％，半衰期ｔ１／２＝０．９３ｓ     

金纳米粒子在平整硅基表面上的组装

采用水相硅烷化方法,将３－氨基丙基－三甲氧基硅烷（ＡＰＳ）组装在湿化学法处理的单晶硅表面上。接触角、原子力显微镜（ＡＦＭ）、Ｘ射线光电子能谱（ＸＰＳ）表征结果显示得到了平整均匀的具有氨基表面的自组装膜。ＳＥＭ观察表明,１６ｎｍ的金纳米粒子可以在上述氨基表面上形成均匀的亚单层排布,得到了具有Ａｕ纳米粒子／ＡＰＳ／Ｓｉ形成的纳米复合结构,进一步的处理可以使金纳米粒子在表面上的排列由随机趋于有序化。     

聚环氧乙烷为支链的两亲共聚物的表征及性能

用端基带有甲基丙烯酸酯的聚环氧乙烷大分子单体（ＰＥＯ—ＭＡ）分别与小分子单体苯乙烯（Ｓ）、甲基丙烯酸甲酯（ＭＭＡ）、丙烯酸甲酯（ＭＡ）溶液自由基共聚合得到了三种具有不同主链结构的以聚环氧乙烷（ＰＥＯ）为支链的两亲接枝嵌段共聚物（分别简写为：ＰＳ─ｇ─ＰＥＯ，ＰＭＭＡ─ｇ─ＰＥＯ，ＰＭＡ─ｇ─ＰＥＯ）．用ＧＰＣ、ＩＲ、１Ｈ─ＮＭＲ、ＷＡＸＤ和ＤＳＣ对其结构进行了表征．研究了接校共聚物的结晶性能、乳化性能以及在Ｗｉｌｌｉａｍｓｏｎ反应中相转移催化作用．结果表明，不同主链结构有不同的结晶度，并随支链ＰＥＯ含量的增加，分子量的增大而提高；其乳化体积和相转移催化反应的转化率均随着共聚物浓度的增加、支链ＰＥＯ含量的增人而增大，随支链ＰＥＯ分子量的提高而减小．     

苯乙烯/甲基丙烯酸和苯乙烯/甲基丙烯酸(β-羟丙酯)嵌段共聚物的表面动态行为

通过测定表面动态接触角研究了两亲性的苯乙烯／甲基丙烯酸嵌段共聚物（ＰＳ ｂ ＰＭＡＡ）和苯乙烯／甲基丙烯酸（β 羟丙酯）嵌段共聚物（ＰＳ ｂ ＰＨＰＭＡ）的表面动态行为及温度、嵌段长度比等因素对其值的影响,讨论了聚合物表面当接触介质改变时链段或基团的再取向行为和表面性质     

（PSF—PDMS—PHS）n／PSF共混物的相容性及表面组成

利用ＤＳＣ、ＤＭＡ、ＴＥＭ和ＸＰＳ对［ＰＳＦ－ＰＤＭＳ－ＰＨＳ］ｎ／ＰＳＦ共混物的相容性及表面组成进行了研究．结果表明，ＰＤＭＳ在共混物表面的富集与ＰＳＦ均聚物和［ＰＳＦ－ＰＤＭＳ－ＰＨＳ］ｎ中硬段的相容性有关；ＰＤＭＳ在相容的共混物体系表面的富集与对应的多嵌段共聚物组成基本相近；不相容共混物体系表面ＰＤＭＳ的富集程度相对较高，当共混物本体中有机硅含量从１％增至５％，表面层ＰＤＭＳ的含量迅速增加，可达到嵌段共聚物中ＰＤＭＳ的含量．     

Dewetting behavior of Langmuir−Blodgett films of polystyrene‐b‐poly(methyl methacrylate) induced by solvent vapor annealing

In order to explore the degree of contact between hydrophilic blocks and the substrate, the dewetting behavior of Langmuir–Blodgett (LB) films of polystyrene‐block‐poly(methyl methacrylate) (PS‐b‐PMMA) induced by PMMA‐selective acetone vapor were investigated by atomic force microscopy (AFM) for the first time. With the annealing of acetone vapor, the LB films of PS‐b‐PMMA undergo the swelling and coalescing of aggregates, the formation of bicontinuous patterns, the formation of droplets, and the periodic increase and decrease of droplets. The emergence of the bicontinuous patterns indicates that the dewetting occurs via the spinodal dewetting mechanism. The periodic droplet evolution is a novel phenomenon observed for the first time and quite different from the single droplet evolution of spin‐coated films, which is probably due to the degree of contact between PMMA blocks and the substrate in the LB films being larger than that in the latter. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 825–830     

Structure and dewetting behavior of polyhedral oligomeric silsesquioxane-filled polystyrene thin films

Polyhedral oligomeric silsesquioxane (POSS) meets increasing interest as a building unit for inorganic-organic hybrid materials. The incorporation of cyclopentyl-substituted POSS (CpPOSS) into polystyrene (PS) thin films led to an inhibition of dewetting. In this paper, the dispersion state of CpPOSS in the CpPOSS/PS hybrid films and, furthermore, the relationships between the structure and dewetting inhibition effect are discussed. Structural analysis of the hybrid films revealed that CpPOSS segregated to the film surface and crystallized. The segregation of CpPOSS to the surface changes the surface free energy and spreading coefficient of the film. Interfacial structure was also roughened by the segregation of CpPOSS, which can contribute to the inhibition of dewetting by pinning the contact line of the PS film with the substrate. The inhibition of dewetting can be attributed to the modification of the film surface and interface by the segregation of CpPOSS.     

Control of dispersion state of silsesquioxane nanofillers for stabilization of polystyrene thin films

The influence of the dispersion states of the nanofillers on the dewetting behavior of the polymer thin film was investigated. Polyhedral oligomeric silsesquioxanes (POSS) with various substituents were added into polystyrene (PS) thin films as the nanofillers. The dewetting rate of the films drastically changed with the surface substituents of POSS additives. Neutron reflectivity measurements indicated that the difference of the dewetting rate was associated with the dispersion state of POSS additives in the films. POSS with phenethyl groups (PhPOSS), which homogeneously dispersed into the films, resulted in the decrease of the glass transition temperature of PS and the enhancement of the dewetting of the films. POSS with a fluoroalkyl group (CpPOSS-R f) segregated to the film surface and showed the retardation of the dewetting by the decrease of the surface energy of the film. POSS with hydroxyl groups (CpPOSS-2OH) segregated to the film surface and film-substrate interface and led to the elimination of the dewetting, suggesting the importance of the interfacial segregation for the inhibition of dewetting. These results revealed the strong relationship between the dispersion state of the nanofillers and the dewetting of the nanofilled films.     

Dewetting of polystyrene thin films on poly(ethylene glycol)-modified surfaces as a simple approach for patterning proteins

A simple technique for patterning proteins utilizing dewetted polystyrene (PS) droplets is demonstrated. A polystyrene thin film was spin coated on a poly(ethylene glycol) (PEG) silane-modified surface. As the PS film dewets from the surface, upon annealing, to form droplets, the PEG-silane-modified surface is exposed, which retains its capability to resist protein adsorption, and the PS droplets allow the selective adsorption of proteins. In contrast to the undewetted flat PS film, the droplet surface had a greater amount of adsorbed proteins. Atomic force microscopy scans reveal that the roughness of the droplet surface is higher, and a multilayer of proteins results on the droplet surface. Moreover, micro- and nanoscale droplet patterns can easily be achieved by tuning the thickness of PS thin films. Because dewetting approaches for generating ordered dewetting droplets have been successfully generated by others, those approaches could be easily combined with this technique to fabricate ordered protein patterns.     

聚醚硅油表面迁移行为对聚苯乙烯表面极性的影响

利用变角衰减全反射傅立叶变换红外光谱(ATR-FTIR)法和接触角,分析了聚醚硅油在聚苯乙烯共混物薄膜表面的选择性富集行为及对其表面结构和表面极性的影响,认为接触介质的表面性质是影响共混物中各组分产生选择性迁移扩散的重要影响因素.强极性介质的诱导作用可以在共混物表面层中产生剧烈变化的浓度梯度,而弱极性介质所产生的表面浓度梯度比较缓和.     

Surface and interface morphology of polystyrene/poly(methyl methacrylate) thin‐film blends and bilayers

The surface and interface morphologies of polystyrene (PS)/poly(methyl methacrylate) (PMMA) thin‐film blends and bilayers were investigated by means of atomic force microscopy (AFM) and X‐ray photoelectron spectroscopy. Spin‐coating a drop of a PS solution directly onto a PMMA bottom layer from a common solvent for both polymers yielded lateral domains that exhibited a well‐defined topographical structure. Two common solvents were used in this study. The structure of the films changed progressively as the concentration of the PS solution was varied. The formation of the blend morphology could be explained by the difference in the solubility of the two polymers in the solvent and the dewetting of PS‐rich domains from the PMMA‐rich phase. Films of the PS/PMMA blend and bilayer were annealed at temperatures above their glass‐transition temperatures for up to 70 h. All samples investigated with AFM were covered with PS droplets of various size distributions. Moreover, we investigated the evolution of the annealed PS/PMMA thin‐film blend and bilayer and gave a proper explanation for the formation of a relatively complicated interface inside a larger PS droplet. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 9–21, 2006     

Surface structures and properties of polystyrene/poly(methyl methacrylate) blends and copolymers

Sum frequency generation (SFG) vibrational spectroscopy has been applied to study the molecular surface structures of polystyrene (PS)/poly(methyl methacrylate) (PMMA) blends and the copolymer between PS and PMMA (PS-co-PMMA) in air, supplemented by atomic force microscopy (AFM) and contact angle goniometer. Both the blend and the copolymer have equal weight amounts of the two components. SFG results show that both components, PS and PMMA, can segregate to the surface of the blend and the copolymer before annealing, although PMMA has a slightly higher surface tension. Upon annealing both SFG results and contact angle measurements indicate that the PS segregates to the surface of the PS/PMMA blend more but no change occurs on the PS-co-PMMA surface. AFM images show that the copolymer surface is flat but the 1:1 PS/PMMA blend has a rougher surface with island like domains present. The annealing effect on the blend surface morphology has also been investigated. We collected amide SFG signals from interfacial fibrinogen molecules at the copolymer or blend/protein solution interfaces as a function of time. Different time-dependent SFG signal changes have been observed, showing that different surfaces of the blend and the copolymer mediate fibrinogen adsorption behavior differently.     

Wettability of polymeric solids by ternary mixtures composed of hydrocarbon and fluorocarbon nonionic surfactants

Contact angle (θ) measurements on poly(tetrafluoroethylene) (PTFE) and polymethyl methacrylate (PMMA) surface were carried out for the systems containing ternary mixtures of surfactants composed of: p-(1,1,3,3-tetramethylbutyl)phenoxypoly(ethylene glycols), Triton X-100 (TX100), Triton X-165 (TX165) and Triton X-114 (TX114), and fluorocarbon surfactants, Zonyl FSN100 (FSN100) and Zonyl FSO100 (FSO100). The aqueous solutions of ternary surfactant mixtures were prepared by adding TX114, FSN100 or FSO100 to binary mixtures of TX100+TX165, where the synergistic effect in the reduction of the surface tension of water (γ(LV)) was determined. From the obtained contact angle values, the relationships between cosθ, the adhesion tension and surface tension of solutions, cosθ and the reciprocal of the surface tension were determined. On the basis of these relationships, the correlation between the critical surface tension of PTFE and PMMA wetting and the surface tension of these polymers as well as the work of adhesion of aqueous solutions of ternary surfactant mixtures to PTFE and PMMA surface were discussed. The critical surface tension of PTFE and PMMA wetting, γ(C), determined from the contact angle measurements of aqueous solutions of surfactants including FSN100 or FSO100 was also discussed in the light of the surface tension changes of PTFE and PMMA under the influence of film formation by fluorocarbon surfactants on the surface of these polymers. The γ(C) values of the studied polymeric solids were found to be different for the mixtures composed of hydrocarbon surfactants in comparison with those of hydrocarbon and fluorocarbon surfactants. In the solutions containing fluorocarbon surfactants, the γ(C) values were different taking into account the contact angle in the range of FSN100 and FSO100 concentration corresponding to their unsaturated monolayer at water-air interface or to that saturated.