两亲接枝共聚物PS-g-N-PEO的合成及表面性能研究——铸膜溶剂及浓度的影响

采用大分子单体法合成了一系列聚苯乙烯接枝壬基酚聚氧乙烯 (PS g NPEO)两亲共聚物 ,采用溶液铸膜法将其在PET表面制膜 ,并利用扫描电子显微镜 (SEM) ,X射线光电子能谱 (XPS) ,衰减全反射红外光谱(ATR)和水接触角 (CA)等手段研究了共聚物组成、铸膜溶剂及浓度对共聚物膜表面形貌、组成及水浸润性能的影响 .结果表明 ,两亲接枝共聚物在不同条件下可形成规则的表面微孔 ,共聚物中NPEO含量越高 ,共聚物膜表面微孔孔径越大 ,对应的水接触角越小 .以THF为铸膜溶剂时 ,制膜浓度越大 ,共聚物膜表面微孔孔径越大 ,对应的水接触角越小 ;而以甲苯为溶剂时 ,制膜浓度对共聚物膜表面形貌影响不大 ,但水接触角要较THF体系显著降低 ,水接触角与浓度关系与THF体系相反 ,制膜浓度越大 ,对应的水接触角越大 .制膜浓度相同时 ,THF作溶剂 ,共聚物膜微孔较大 ,表面亲水组分含量较低 ;以甲苯为溶剂 ,微孔较密 ,表面亲水组分较高 .     

含有机硅三元多嵌段共聚物表面的研究

对聚砜（PSF）、聚二甲基硅氧烷（PDMS）和聚对羟基苯乙烯（PHS）的三元多嵌段共聚物[PSF－PDMS－PHS]n的形态和表面组成进行了研究，结果表明溶液成膜后，组成不同的聚合物样品的表面都有有机硅（PDMS）的富集．在用溶剂处理后，富集于膜表面的有机硅含量与所用溶剂的溶度参数有关，一般均下降，但是用水处理后，表面层有机硅的含量却增加     

分子水平研究不同嵌段结构苯乙烯/丁二烯共聚物的表面结构

利用具有准单分子层灵敏度的和频振动光谱(SFG)、原子力显微镜(AFM)和接触角(CA)测定技术研究链结构和溶剂对苯乙烯(S)/丁二烯(B)嵌段共聚物表面准分子层化学结构形成的影响.结果表明,两嵌段共聚物SB比三嵌段共聚物SBS更有利于聚丁二烯(PB)组分在膜表面富集.利用PB的选择性溶剂环己烷做溶剂时,SB膜表面层完全由纯的PB组分组成,而SBS表面则是聚苯乙烯(PS)与PB二组分共存.利用PS的选择性溶剂甲苯做溶剂时,SB与SBS表面都是PS与PB二组分共存,其中SBS表面PS组分的含量更高.原因是由于溶剂影响嵌段共聚物分子在溶液中的构象从而影响溶剂挥发后聚合物表面结构的形成.     

不同极性微量选择性溶剂对聚合物膜表面浸润性的控制

通过在双亲性三嵌段共聚物( PEO-PDMS-PEO)的溶液中加入不同极性的微量选择性溶剂, 分别制得胶束和反胶束微粒, 不同组分的溶液涂膜后显示出明显的浸润性差异. 采用透射电镜、原子力显微镜和X射线光电子能谱分别对胶束和反胶束微粒在溶液中和成膜后的结构以及表面化学组成进行了表征, 结果表明, 不同选择性溶剂所形成的胶束和反胶束微粒的结构差异, 导致了涂膜的表面化学组成的不同, 最终影响其表面浸润性.     

含氟丙烯酸酯共聚物制备超疏水表面及其形成机理的研究

以丙烯酸全氟烷基乙基酯和甲基丙烯酸甲酯为共聚单体, 分别以用微乳液聚合法和溶液聚合法制备的无规共聚物和用可逆加成-断裂链转移制备的嵌段共聚物作为成膜共聚物, 并以1,1,2-三氟三氯乙烷作为溶剂, 采用溶剂挥发成膜法可以直接制备出超疏水膜, 聚合物膜对水的接触角可达160°. 改变聚合物结构和成膜条件, 探讨了该类超疏水膜的形成机理和影响因素. 发现膜的表面形貌和疏水性与共聚物的组成、结构、分子量以及成膜条件密切相关, 随着共聚物中氟含量的增大, 膜的表面形貌都趋于平滑; 而且, 无规共聚物比嵌段共聚物更易形成粗糙度好的膜; 同时, 较大的聚合物分子量和适宜的高的成膜温度都对形成粗糙结构有利.     

PS-b-PAA嵌段共聚物修饰的智能表面的制备及其响应行为的研究

利用原子转移自由基聚合(ATRP), 再经水解后得到了嵌段共聚物聚苯乙烯-b-聚丙烯酸(PS-b-PAA), 接枝到硅烷偶联剂γ-(2,3环氧丙氧)丙基三甲氧基硅烷[γ-(2,3-glycidoxypropyl)trimethoxysilane, GPS]修饰的Si表面得到了对溶剂具有响应性的智能表面, 并通过凝胶渗透色谱(GPC)、傅立叶变换红外光谱(FTIR)、核磁共振(¹H NMR)和原子力显微镜(AFM)等测试手段对产物进行了表征. 然后, 通过接触角测试研究了所得智能表面对不同溶剂的响应行为. 结果显示, PS-b-PAA接枝表面的润湿性与接枝共聚物的组成及表面处理的溶剂性质有关. 在相同的溶剂处理条件下, 共聚物中PS/PAA比值越小, 表面亲水性越大; 乙醇和碱性溶液处理后的表面呈亲水状态, 甲苯和酸性水溶液处理后的表面又切换到疏水状态, 同时其表面的酸碱响应行为具有非常稳定的可逆性.     

带有羧基的含氟丙烯酸酯共聚物的制备及超疏水性能研究

以甲基丙烯酸、甲基丙烯酸甲酯、甲基丙烯酸全氟烷基乙基酯为单体,以可逆加成-断裂链转移方法合成含氟嵌段共聚物,同时以常规自由基溶液聚合制备相似组成的无规共聚物.采用溶剂挥发成膜方法成膜,研究共聚物组成与结构对膜表面形貌和疏水性能的影响.结果表明,羧基单体的引入改变了含氟丙烯酸酯聚合物的溶解性能和成膜性能,使用常用溶剂就可...     

聚醚型非离子表面活性剂的混合表面膜 II: 环氧乙烷环氧丙烷共聚物与异辛基苯酚聚氧乙烯加成物和聚丙二醇的混合膜

本文进一步测定了环氧乙烷环氧丙烷共聚物与异辛基苯酚聚氧乙烯加成物和聚丙二醇等分子混合物在40%NaNO3水溶液表面所成膜的表面压(π)-分子面积(a)关系. 结果表明组成混合膜的两种组份可能形成了完全混溶的二维溶液.     

聚醚型非离子表面活性剂的混合表面膜 II: 环氧乙烷环氧丙烷共聚物与异辛基苯酚聚氧乙烯加成物和聚丙二醇的混合膜

本文进一步测定了环氧乙烷环氧丙烷共聚物与异辛基苯酚聚氧乙烯加成物和聚丙二醇等分子混合物在40%NaNO3水溶液表面所成膜的表面压(π)-分子面积(a)关系. 结果表明组成混合膜的两种组份可能形成了完全混溶的二维溶液.     

成膜因素控制的SIS膜表面环境响应行为

利用和频振动光谱、原子力显微镜及接触角技术研究了不同成膜溶剂、制膜方式所得苯乙烯/异戊二烯/苯乙烯嵌段共聚物(SIS)膜的表面结构及其对溶剂蒸气的响应行为.发现环己酮为溶剂的浇铸膜及甲苯为溶剂的旋涂膜表面润湿性随环己烷和丁酮蒸气交替处理发生变化;甲苯和环己烷为溶剂的浇铸膜表面性质不随溶剂蒸气处理而变化.原因是不同制样条件所获SIS膜具有不同的初始相分离结构.当聚合物膜形成远离平衡态的相分离结构时,分子聚集态转变的能垒较低,易于在溶剂蒸气诱导下转变为新的结构.反之,则不利于链构象转变,形成不同的聚集态结构.这将导致不同制备条件所得SIS膜经溶剂蒸气处理后形成不同的表面结构,呈现出各异的环境响应行为.本研究为智能界面材料的设计和制备提供了新思路.     

Aggregative behavior of AB and ABC block copolymers in the solid phase and in a nonselective solvent

Effects of the amount of chemically dissimilar blocks (two or three) and their polarity on the aggregative behavior of АВ and АВС linear block copolymers of various compositions that are based on polystyrene, poly(n-butyl acrylate), and either poly(acrylic acid) or poly(tert-butyl acrylate) in bulk and in the nonselective solvent DMF are studied via differential scanning calorimetry and dynamic light scattering. АВ block copolymers composed of two chemically dissimilar blocks in the diluted solution in DMF are fully dispersed into macromolecular coils. However, the simultaneous incorporation of three incompatible blocks of different polarities (polystyrene, poly(acrylic acid), and poly(n-butyl acrylate)) into the copolymer is accompanied by a well-defined segregation of blocks in the nonselective solvent, regardless of the composition of the block copolymer and the length and sequence of blocks. This phenomenon makes itself evident as the formation of intermacromolecular aggregates in diluted solutions with a mean hydrodynamic radius of 60–120 nm that are stable in the range 10–60°C. A decrease in the level of the thermodynamic incompatibility of blocks (replacement of a poly(acrylic acid) polar block with a less polar poly(tert-butyl acrylate) block) or the selective improvement of solvent quality with respect to the polar block (the addition of LiBr to DMF) suppresses the segregation of blocks and may lead to the formation of a molecularly dispersed solution of the block copolymer.     

用含氟丙烯酸酯无规共聚物制备超疏水膜

用微乳液聚合法制备了丙烯酸全氟烷基乙酯和甲基丙烯酸甲酯的无规共聚物,并对其进行了表征.采用溶剂挥发成膜法一步制备了具有超疏水性的该聚合物膜,水滴在该聚合物膜上的静态接触角可达151°~160°,滚动角小于3°.通过扫描电子显微镜观察发现该聚合物膜表面分布了许多乳突状突起和微孔洞,并具有微米和纳米尺度相结合的复合杂化结构.该类超疏水表面的形成是由适度粗糙的表面和低表面能相互结合引起的.探讨了该类超疏水膜的形成机理.     

Synthesis and surface properties of fluorinated block copolymers containing sulfonic groups

A series of fluorinated block copolymers with different fluorinated block lengths and compositions were synthesized by atom transfer radical polymerization (ATRP), and then the block copolymers containing sulfonic groups with various sulfonation levels were successfully prepared further via a sulfonation reaction. These well‐defined block copolymers were characterized by means of Fourier transform infrared (FTIR), ¹H‐nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The surface activities of the fluorinated block copolymers containing sulfonic groups in N‐methyl pyrrolidone solution and the surface properties of the films prepared from such a solution were examined, and the experimental results showed that the fluorinated block copolymers exhibited a high surface activity in solution and quite a low solid surface energy of films, even though they contain hydrophilic sulfonic groups. The critical surface tensions of these copolymers were estimated and were comparable to that of polytetrafluoroethylene. Even more interestingly, the surface activities of the block copolymers containing sulfonic groups or sodium sulfonate groups in aqueous solution were also measured. It was found that the surface activity in aqueous solution was weaker than that in N‐methyl pyrrolidone solution and depended on both the length of the fluorinated block and the sulfonation level of the block copolymers. The surface properties of the films prepared from the block copolymers in aqueous solution were tested, and most of these films exhibited a hydrophilic surface property. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4809–4819, 2004     

Synthesis, characterization and surface properties of amphiphilic polystyrene-b-polypropylene glycol block copolymers

The new macroazoinitiators containing poly (propylene glycol), (PPG), with molecular weight 400 and 2000, having hydrophilic character, were synthesized and polymerized with styrene to prepare PS-b-PPG block copolymers. Cast films and e-spun films were prepared and contact angles of these films with water drop were measured to examine hydrophilic/hydrophobic behavior of the copolymers. Each e-spun film with average fiber diameters from 0.25 to 2.20 μm was prepared in N,N-dimethylformamide (DMF) under controlled electrospinning process parameters such as polymer concentration, applied voltage and tip-to-collector distance. Scanning electron microscope (SEM) images of the electrospun films were taken to determine the fiber diameters. Surface compositions of the block copolymers were also determined by using an electron spectrometer with Mg Kα X-rays. NMR, and FT-IR spectroscopic, and GPC measurements were employed to characterize and determine the PPG contents (6-43%). From the results, electrospinning process increased the hydrophilic properties of the block copolymers obtained, compared their cast film forms. Our results suggest that these polymers are favorable in biological applications in cases where high ratio of the surface to volume and hydrophilicity are required simultaneously. Both chemical structure and topology of the films are important in wetting and hydrophobicity.     

含羧基的含氟嵌段共聚物的合成及表面性能研究

利用原子转移自由基聚合反应以及随后的大分子链中叔丁酯基团的水解反应,合成了一系列具有不同含氟量和羧基含量的二嵌段共聚物,并分别通过GPC, ¹H NMR和FT-IR对共聚物的组成和结构进行了表征.进一步考察了这些含羧基或羧酸钠基团的含氟嵌段共聚物在吡咯烷酮或水中的溶解性能、临界胶束浓度、表面活性、达到饱和吸附时每个分子在表面所占据的面积,以及成膜后的临界表面张力等性能.实验结果表明,此含氟嵌段共聚物能显著降低吡咯烷酮和水的表面张力,成膜后表现出与聚四氟乙烯极为接近的低表面能特性.     

Lamellar orientation in thin films of symmetric semicrytalline polystyrene-b-poly(ethylene-co-butene) block copolymers: effects of molar mass, temperature of solvent evaporation, and annealing

Orientation of the lamellar microdomains in thin films of three symmetric polystyrene-b-poly(ethylene-co-butylene) block copolymers (S65E155, S156E358, and S199E452) on mica was investigated via atomic force microscopy (AFM), grazing incidence X-ray diffraction (GIXRD) and X-ray photoelectron spectroscopy (XPS). The results show that lamellar orientation in the SxEy block copolymers greatly depends on the molar mass of the block copolymers, the temperature of solvent evaporation, and annealing. The nascent thin film of the low molar mass block copolymer, S65E155, shows a multilayered structure parallel to the mica surface with the PS block at both polymer/mica and polymer/air interfaces, but the high molar mass block copolymers, S156E358 and S199E452, exhibit a structure with lamellar microdomains perpendicular to the mica surface. When the solvent is evaporated at a lower temperature, the crystallization rate is fast and a two-dimensional spherulite structure with the lamellar microdomains perpendicular to the mica surface is observed. Annealing of all the thin films with lamellar microdomains perpendicular to the mica surface leads to morphological transformation into a multilayered structure parallel to the mica surface. In all SxEy thin films on mica, the stems of PE crystals are always perpendicular to the interface between the lamellar PE and PS microdomains. A mechanism is proposed for the formation of different microdomain orientations in the thin films of semicrystalline block copolymers. When the thin film is prepared from a homogeneous solution, microdomains perpendicular to the substrate surface are formed rapidly for strongly segregated block copolymers or at a lower crystallization temperature and kinetically trapped by the strong segregation strength or solidification of crystallization, while for weakly segregated block copolymers or at slower crystallization rate, the orientation of the microdomains is dominated by surface selectivity.     

Copolymerisation radiochimique du styrene avec l'acrylonitrile en solution

The radiation-initiated copolymerization of styrene and acrylonitrile was investigated at 20° in dimethylformamide (DMF) and in benzylalcohol solutions. The compositions of the copolymers were only slightly affected by these polar solvents. The influence of temperature on the copolymerization in DMF solutions was studied in greater detail. It was found that the acrylonitrile content in the copolymer obtained at -78° drastically increased as a result of an anionic polymerization of acrylonitrile. Fractional precipitation of the products obtained at -78° showed that they were not mixtures of polymers but were block copolymers containing long sequences of acrylonitrile units. This copolymer is assumed to arise as a result of the simultaneous growing of the two ends of a primary radical-ion, acrylonitrile adding to one end by an anionic mechanism while the free radical end initiates a random copolymerization of styrene and acrylonitrile. The anionic contribution to the over-all process was established. The anionic homopolymerization of acrylonitrile was studied in DMF, toluene and their mixtures. The rate was found to exhibit a maximum for 20% acrylonitrile in DMF. It was further noticed that significant amounts of DMF could be replaced by toluene or styrene without affecting the rate. The reduction in rate in more concentrated monomer solutions was attributed to an autoinhibition of acrylonitrile in its anionic polymerization.     

Preparation and Surface Properties of Fluorine‐Containing Diblock Copolymers PLMA‐Block‐PFAEA

A series of fluorine‐containing diblock copolymers based on lauryl methacrylate and 1H,1H,2H,2H‐perfluoroalkyl acrylate have been prepared by atom transfer radical polymerization (ATRP). The preparation process of PLMA‐Br macroinitiators was controlled within a reasonable time corresponding to the ln [M₀]/[M_t]～time plot of the reaction. FTIR, ¹H‐NMR, GPC and fluorine‐element analysis (FEA) were used to characterize the synthesized block copolymers. The solid surface activity of these polymers was demonstrated by contact angle measurement. The polymer films prepared by block copolymers with more than three fluorinated units showed low dispersion force contributions to the surface energy indicating the presence of the fluorinated block at the surface. The surface activity in solutions was measured by drop‐weight method. Ii is interesting to find, when the fluorine weight percentage is controlled constant, that PLMA‐b‐PFAEA with larger molecular size is more prominent in exploiting the fluorinated structure to reduce the surface tension of solutions. The block copolymer's ability in reducing surface tension of solutions also depends on the type of solvent.     

Roll-Casting of block copolymers and of block copolymer-homopolymer blends

An improved technique for casting highly oriented films of block copolymers from solutions subjected to flow is presented. Polymer solutions were rolled between two counter-rotating adjacent cylinders while at the same time the solvent was allowed to evaporate. As the solvent evaporated, the block copolymers microphase separated into globally oriented structures. Using this method known as ‘roll-casting’ we present in this paper a study of the morphology of polystyrene-polybutadiene-polystyrene (PS/PB/PS) triblock copolymer cast with and without additional high molecular weight homopolymers. The pure copolymer films consisted of polystyrene cylinders assembled on a hexagonal lattice in a polybutadiene matrix in a near single-crystal structure. Blends of copolymer with high molecular weight polystyrene and/or polybutadiene, phase separated into ellipsoidal regions of homopolymer embedded in an oriented block copolymer matrix. Annealing the films resulted in conversion of the homopolymer regions to spheres accompanied by some misalignment of the copolymer microdomains. The morphology of these films as revealed by TEM is discussed. A brief discussion of the flow field that develops in the experimental system is also presented and its similarity to the flow field of our previous work is shown. © 1994 John Wiley & Sons, Inc.