基于聚合物刷微图案的生物素化梯度表面制备研究

提出了基于叠氮功能化聚合物刷微图案制备生物素化梯度表面的方法 .通过数字微镜器件(DMD)调控光辐照引发表面原子转移自由基聚合(ATRP)反应,制备叠氮功能化的聚(2-(2-叠氮-2-甲基丙氧基)甲基丙烯酸乙酯)(PAMEMA)聚合物刷微图案,采用X射线光电子能谱仪(XPS)和飞行时间二次离子质谱仪(TOF-SIMS)对PAMEMA聚合物刷微图案的化学组成及分布进行表征,表明叠氮基团在聚合物刷图案化表面的区域选择性分布;以叠氮基团为反应位点,通过点击化学反应实现PAMEMA聚合物刷微图案表面的生物素化,借助荧光标记的链霉亲和素染色实验表征生物素在微图案表面的分布情况;以具有厚度变化的PAMEMA聚合物刷微图案为模板制备生物素表面,结果表明通过控制聚合物刷的厚度可以对微图案表面固定生物素分子的空间密度进行调控以实现具有复杂结构的生物素化梯度表面的成功制备.     

微图案化钙磷盐膜层的电化学构筑及其生物性能

基于表面分子自组装和光催化转印技术,在TiO2膜层表面获得超亲/超疏水阵列微图案模板,结合电化学沉积技术,成功制备了微图案化钙磷盐膜(CaP)层.扫描电子显微镜(SEM)和电子探针分析(EPMA)结果表明,通过超亲/超疏水阵列微图案模板可构筑高空间分辨的微图案化钙磷盐膜层.微图案化钙磷盐膜层的体外MG-63细胞培养证实,细胞对钙磷盐膜层微单元有强烈的选择性粘附作用,从而可望控制细胞在微单元中的贴壁生长,实现高通量评价细胞行为.     

图案化TiO2薄膜的制备技术

本文综述了图案化TiO2薄膜的制备技术,按图案的生成方式可分为图案的直接生成,掩膜复制法,硬质模板复制法三大类。可以通过针尖写蚀法、电子书写蚀法、激光写蚀法、自组装法、光电化学法直接制备图案。掩膜复制法包括光刻胶法、自组装膜法、光敏凝胶膜法等。硬质模板法也称软刻蚀技术,分为复制微模塑、转移微模塑、毛细管微模塑、微接触印刷法、光-盖印印刷等技术。对每类方法的优缺点作了适当评述,对今后图案化TiO2薄膜制备的研究方向提出了一些建议。     

红外驱动的动态褶皱图案:一种实现智能材料表面的有效途径

响应性表面微纳米图案可以通过外界刺激动态调控表面微纳米结构,从而实现对材料表面性能的动态调控。其中,利用材料表面不稳定性构筑褶皱是制备表面微纳米图案的通用方法,然而如何实现微纳米褶皱图案的动态调控仍然面临挑战。上海交通大学姜学松研究团队在刺激响应性高分子表面方面开展的研究工作取得了一系列阶段性成果。最近该团队提出了一种简单、普适的制备具有近红外光响应性的动态微纳米表面褶皱图案的策略,实现了对材料表面微纳米结构的多重刺激响应性调控,为构建智能材料表面开辟了新途径。     

硅基图案化TiO2表面微结构的制备和表征

结合微接触印刷术和TiO₂沉积成膜技术,在单晶硅表面成功地制备了具有微米级图案结构的TiO₂薄膜,并利用XPS,SEM和AFM对其表面性质和结构进行了表征.该硅基图案化TiO₂微结构在光电转化、微机电和光催化等领域中的应用具有重要意义.     

表面微图案化聚乳酸膜的制备及其细胞亲和性评价

利用溶剂-非溶剂法(SNS)制备表面具有微孔图案的聚乳酸(PLA)膜和聚苯乙烯(PS)膜,并以微孔PS膜为模板,构建表面具有微岛图案的PLA膜.以此为基础,对所制备的微图案表面对PLA膜亲/疏水性及成骨细胞粘附与增殖性能的影响进行研究.结果显示微图案的存在显著增强了PLA膜的表面疏水性(水接触角90°);成骨细胞在微图案表面具有良好的铺展性,其黏附数量明显高于光滑PLA膜,但细胞的生长曲线相对较平缓,显示微图案表面虽有利于细胞在PLA膜表面的粘附与铺展,但对促进细胞的增殖无贡献.     

薄层软刻蚀法制备PMMA微图案结构

对现有的软刻蚀方法提出了改进,让其与压印技术及毛细力刻蚀技术相结合形成一种薄层软刻蚀技术,并以这种技术制备出PMMA薄膜微图案化结构.在30 mm/h的拉膜速度以及弹性印章表面图形深度确定不变的情况下,PMMA流体能够完全填充到弹性印章的微通道中,SEM和光学显微镜照片证明得到的PMMA微图案是相互分离的.因此,薄层软刻蚀技术可以克服普通微模塑方法制备分离图形困难和纳米压印技术中需要使用巨大机械压力的缺点.     

热微接触印刷制备酚醛树脂微纳米图案

以酚醛树脂(PF)为热交联物质,添加交联剂2,4,6-三[双(甲氧基甲基)氨基]-1,3,5-三嗪和产酸剂二苯基碘鎓六氟磷酸盐,表面带有精细微纳米图案的聚二甲基硅氧烷(PDMS)作为印章,采用热微接触印刷(hotμCP)技术制备热交联聚合物的微纳米图案.通过扫描电子显微镜(SEM)和接触角测量仪对精细结构图案进行表征.结果表明,这种简单、快速、低成本的hotμCP法能够成功地实现热交联聚合物的图案化,且最小尺度可接近100nm.     

扫描探针氧化刻蚀技术在微纳器件制备中的应用

扫描探针刻蚀技术主要利用原子力显微镜针尖和基底间的电、机械或热相互作用进行纳米级表面的成像、操纵和修饰,是一种简便、快速、精确的纳米结构制备技术.其中,扫描探针氧化刻蚀技术利用针尖与样品表面间形成的高度局域化水桥,通过电化学反应在材料表面制备微纳尺度结构,已被广泛用于制备纳米级功能化图案和微纳器件.本文对扫描探针氧化刻蚀过程的机理及其影响因素,如电压、针尖-样品间作用力、持续时间、相对湿度和扫描速度等进行了详细介绍,总结和梳理了利用这一技术制备微纳器件方面的工作,指出了其优点和存在的问题,并对其未来发展进行了展望.     

蛋白质图案构筑及其应用研究进展

蛋白质作为生物体内一类重要的大分子已被广泛地应用于构筑图案化结构, 所得到的蛋白质图案在医疗诊断、组织工程、生物传感和药物筛选等领域均表现出了巨大的应用价值. 目前, 蛋白质图案的构筑方法主要有两种： （1） 在利用微加工技术制备的微结构上进行蛋白质的后续接枝实现蛋白质图案的构筑; （2） 直接用蛋白质分子构筑图案化结构. 本文对当前常用的蛋白质图案构筑技术进行了综述, 并对蛋白质图案的实际应用进行了总结, 最后对蛋白质图案构筑技术的发展方向以及蛋白质图案的应用前景进行了展望.     

利用胶体探针技术研究多巴与纳米、微米及微纳复合结构表面之间的相互作用

通过在硅片表面有机蒸镀不同厚度的二十九烷制备了不同晶体密度的仿生旱金莲叶面蜡质纳米结构表面,采用端基修饰多巴的原子力显微镜胶体探针,对各纳米结构表面进行了粘附性能测试,发现蒸镀200 nm厚度二十九烷结晶的纳米结构表面具有较低粘附力。采用反应离子刻蚀方法制备了不同高度的硅材质仿生鲨鱼皮微米结构表面,并选择了200 nm厚度二十九烷在仿生鲨鱼皮表面进行有机蒸镀制备了微纳复合结构表面,通过胶体探针的研究发现多巴与高度为1、3、5μm微纳复合结构表面的粘附力均小于与200 nm厚度二十九烷结晶的纳米结构表面之间的粘附力,说明微纳复合结构表面具有很强的抗多巴粘附能力,并且这种复合结构表面相对于硅材质的仿生鲨鱼皮微米结构表面还兼有旱金莲叶面的强疏水性和极佳的抗水粘附能力。     

Preparation and characterization of functional group gradient surfaces

Functional group gradient surfaces where the density of functional groups changes gradually along the sample length were prepared. The functional group (? COOH, ? CONH₂, and ? OH group) gradient surfaces were produced by the treatment of low-density PE sheets using a corona with gradually increasing power, followed by the graft copolymerization of acrylic acid and subsequent substitution reaction of carboxylic acid groups to amide or hydroxyl groups. The prepared gradient surfaces were characterized by the measurement of water contact angle, FTIR-ATR, and ESCA. The gradient surfaces prepared can be used to systematically investigate the interactions of biological or other species in terms of the surface functional groups and their density of polymeric materials. © 1994 John Wiley & Sons, Inc.     

Conversion of a metastable superhydrophobic surface to an ultraphobic surface

Superhydrophobic surfaces in Wenzel and metastable wetting state were prepared and the conversion of such surfaces to ultraphobic surfaces was reported by the application of a fine-scale roughness. Silicon nitride substrates with hexagonally arranged pillars were prepared by micromachining. The two-scale roughness was achieved by coating these substrates with 60 nm silica nanoparticles. The surface was made hydrophobic by silanization with octadecytrichlorosilane (OTS). Wettability studies of the silicon nitride flat surface, silicon nitride pillars, and the surfaces with two-scale roughness showed that a two-scale roughness can effectively improve the hydrophobicity of surfaces with a higher apparent contact angle and reduced contact angle hysteresis when the original rough surface was in a metastable or Wenzel state. This study shows the pathway of converting a metastable hydrophobic surface to an ultraphobic surface by the introduction of a fine-scale roughness, which adds to the literature a new aspect of fine-scale roughness effect.     

Crystal-face dependences of surface band edges and hole reactivity, revealed by preparation of essentially atomically smooth and stable (110) and (100) n-TiO(2) (rutile) surfaces

Essentially atomically smooth (100) and (110) n-TiO(2) (rutile) surfaces were prepared by immersion of commercially available single-crystal wafers in 20% HF, followed by annealing at 600 degrees C in air. The obtained surfaces were stable in aqueous solutions of pH 1-13, showing no change in the surface morphology on an atomic level, contrary to atomically flat surfaces prepared by ion sputtering and annealing under UHV. The success in preparation of the atomically smooth and stable n-TiO(2) surfaces enabled us to reveal clear crystal-face dependences of the surface band edges and hole reactivity in aqueous solutions.     

A facile method for preparing sticky, hydrophobic polymer surfaces

Textured surfaces consisting of nanometer- to micrometer-sized lightly sulfonated polystyrene ionomer (SPS) particles were prepared by rapid evaporation of the solvent from a dilute polymer solution-cast onto silica. The particle textured ionomer surfaces were prepared by either spin-coating or solution-casting ionomer solutions at controlled evaporation rates. The effects of the solvent used to spin-coat the film, the molecular weight of the ionomer, and the rate of solvent evaporation on the surface morphology of cast films were investigated. The surface morphologies were consistent with a spinodal decomposition mechanism, where the surface first existed as a percolated-like structure and then ripened into droplets if molecular mobility was retained for sufficient time. The SPS particles or particle aggregates were robust and resisted separation from the surface even after annealing at 120 °C for 1 week. The water contact angles on as-prepared surfaces were relatively low, ～90°, due to the polar groups in the ionomer, but when the surface was modified by chemical vapor deposition of 1H,1H,2H,2H-perfluorooctyltrichlorosilane, the surface contact angles increased to ～109° on smooth surfaces and up to ～140° on the textured surfaces. Although the surfaces were hydrophobic, the contact angle hysteresis was relatively high and water droplets stuck to these surfaces even when the surface was turned upside down.     

Effect of reaction solvent on the preparation of thermo-responsive stationary phase through a surface initiated atom transfer radical polymerization

Poly(N-isopropylacrylamide) (PIPAAm) brush grafted silica beads, a thermo-responsive chromatographic stationary phase, were prepared through a surface-initiated atom transfer radical polymerization (ATRP) using 2-propanol, N,N-dimethylformamide (DMF), and water as reaction solvents. The rate of grafting PIPAAm on silica bead surfaces was different and found to be dependent on the reactivity of reaction solvent. Temperature-dependent elution profiles of hydrophobic steroids from the prepared-beads-packed columns were found to be different, although the graft amounts of PIPAAm were similar on silica bead surfaces. Especially, prepared beads using 2-propanol exhibited a higher resolution than those using DMF. Calibration curves using glucose and pullulan suggested that beads prepared using DMF prohibited analytes to diffuse into the pores. On the contrary, beads prepared using 2-propanol allowed analytes to diffuse into the pores. The pore diameter of the prepared beads, measured by N(2) adsorption-desorption measurement, suggested that beads using 2-propanol has relatively larger pore diameter than those using DMF. Thus, the reaction solvent in surfaces-initiated ATRP affected the grafting configuration of PIPAAm on porous silica-bead surfaces, leading to the different separation efficiency of stationary phase for bioactive compounds.     

Surface forces measurements of spin-coated cellulose thin films with different crystallinity

A systematic study of the surface forces between a cellulose sphere and cellulose thin films of varying crystallinity has been conducted as a function of ionic strength and pH. Semicrystalline cellulose II surfaces and amorphous cellulose films were prepared by spin-coating of the precursor cellulose solutions onto oxidized silicon wafers before regeneration in water. Crystalline cellulose I surfaces were prepared by spin-coating wafers with aqueous suspensions of sulfate-stabilized cellulose I nanocrystals. These preparation methods produced thin, smooth films suitable for surface forces measurements. The interaction with the cellulose I was monotonically repulsive at pH 3.5, 5.8, and 8.5 and at 0.1, 1, and 10 mM ionic strengths. This was attributed to the presence of strongly ionizable sulfur-containing groups on the cellulose nanocrystal surfaces. The amorphous film typically showed a steric interaction up to 100 nm away from the interface that was independent of the solution conditions. A range of surface forces were successfully measured on the semicrystalline cellulose II films; attractive and repulsive regimes were observed, depending on pH and ionic strength, and were interpreted in terms of van der Waals and electrostatic interactions. Clearly, the forces acting near cellulose surfaces are very dependent on the way the cellulose surface has been prepared.     

Synthesis and Properties of Dendronized Chitosan

Summary: Chitosan films and microspheres were prepared and their surfaces were functionalized with first generation dendritic molecules. The films were modified by Weisocyanate dendron, while Behera's and bis Behera's amine dendrons were used to modify the microspheres. Prior to dendronization films were prepared by blending chitosan with 18% of polyvinyl pyrrolidone (PVP), and casting the resulting mixture. The degree of dendronization reached was 28%. The microspheres were prepared by coacervation/precipitation, after which the surfaces were activated with either epychlorohydrine (ECH) or 1,4-butanediol diglycidyl ether (BDGE). The oxirane groups were utilized to form covalent bonds between chitosan and dendrons. The degree of dendronization yielded with Behera's amine was 60% for both activating agents. When bis Behera's amine was used, the dendronization reached values of 15 and 21% when ECH or BDGE were used, respectively. The dendronized products were characterized through spectroscopic and microscopic studies and by determination of swelling indexes. Only one of the surfaces was dendronized in every film, which therefore presented a hydrophobic and a hydrophilic surface. Since these films maintain the properties of chitosan, they offer interesting potential as dressings for exuding wounds. The different surfaces make the microspheres potentially applicable as carriers for delivery and controlled release of drugs.     

Comparison of surface modification techniques used for the preparation of wall coated open tubular glass capillary columns

Summary Comparison of different techniques for modifying internal glass surfaces to accept a substrate loading on wall coated open tubular columns (WCOT) were examined. Inner surfaces pretreated with a non-extractable Carbowax 20M layer, barium carbonate and silica whiskers were prepared and coated with a Carbowax 20M liquid phase. The columns were evaluated for efficiency, acidic-basic and adsorption properties, thermal stability and coating efficiency. Column performances were also assessed for deactivated surfaces. Each column was applied to a standard mixture of Aroclor 1016.     

三种钢基疏水表面微观形貌的分形特征及其对润湿性的影响

采用化学刻蚀与低表面能物质修饰相结合的方法, 通过调控刻蚀时间在304不锈钢、 X80管线钢和45#钢表面构造不同的微观形貌; 借助扫描电子显微镜采集不同材料表面的微观形貌, 并采用接触角测量仪测量其润湿性能; 应用Matlab软件编程计算分形参数. 结果表明, 3种材料构造的疏水表面均具有分形特征, 且最佳刻蚀时间为30 min, 此时多重分形谱子集维数最大值最靠左, 对应的奇异性指数最小, 表征表面微观形貌的分形维数也达到最大值; 分形维数与接触角线性拟合效果优良, 接触角随分形维数的增大而增大.