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941.
合成了一种新颖的乙炔衍生物,2-甲基-8-(9,9-二丁基芴)-3,5,7-三炔-2-辛醇(6a),并利用红外光谱(IR),紫外光谱(Uv),核磁(NMR),质谱(MS)等对其结构进行了表征。利用红外光谱(IR)和紫外光谱(Uv)对其拓扑固相聚合性质进行了研究。实验结果表明,这些化合物在加热和紫外光照射条件下都能够发生固相聚合,但得到的是结构复杂的聚合物。  相似文献   
942.
Yves Martin 《Thin solid films》2007,515(17):6844-6852
Plasma polymerization processes are widely used to chemically functionalize surfaces, which properties can be tuned by different operating variables. In this study, thin amine-containing polymer layers were produced on solid substrates in a custom-made cylindrical plasma polymerization reactor by radio frequency glow discharges of n-heptylamine vapours. Carefully planned experiments were conducted to evaluate the importance of four different process parameters on the chemical composition and thickness of the resulting films. The parameters investigated were: 1) deposition time, 2) power of the glow discharge, 3) distance between the electrodes, and 4) monomer pressure. Possible interactions between these variables were investigated through the use of statistical analyses (i.e., factorial design). This study reveals that n-heptylamine plasma polymer (HApp) layer thickness is influenced by the power of the glow discharge and the deposition time, as assessed by surface plasmon resonance and atomic force microscopy step height measurements. Also, the atomic ratio of nitrogen to carbon atoms on the treated surfaces is mainly influenced by the power of the glow discharge, as revealed by X-ray photoelectron spectroscopy. Quartz crystal microbalance analysis also confirmed that HApp layers are stable when immersed in aqueous solution.  相似文献   
943.
We have developed a diffusion-controlled size-selective method for sensing chloride ion in the presence of bromide ion, based on a thin, nanoporous, plasma-polymerized coating of hexamethyldisiloxane on an Ag/AgCl electrode. Sub-nanometer-sized pores responsible for a highly cross-linked polymer network in the plasma-polymerized coating allowed diffusion-controlled permeation of chloride ion while blocking the larger bromide ion. An electrode coating of thickness greater than 70 nm enabled chloride detection in the concentration range 1-10 mM in the presence of 0.63 mM bromide ion. Advantages of this approach are: (1) simple design compared with ionophore-based strategies and (2) compatibility with microfabrication and mass production processes.  相似文献   
944.
A high-yielding synthesis afforded a hexa-peri-hexabenzocoronene carrying acrylate units at the end of six attached alkyl spacers. The polymerization of these acrylate moieties could be initiated with thermal energy and through direct photoactivation without the addition of a photoinitiator. This allowed the organization of the liquid-crystalline material to be fixed in either the crystalline state or the mesophase, which preserved the organization in the respective phase. The use of a focused synchrotron beam permitted selected regions of a thin film to be rendered insoluble. After "developing" the film in this lithographic process by dissolving the soluble, unpolymerized material, defined nano-objects remained on the substrate. In addition, the pronounced aromatic pi stacking of the novel material allows an organization in mesoporous membranes that could be fixed by thermal crosslinking. After the removal of the inorganic template, mechanically stable nanotubes were obtained, which were characterized by different microscopy techniques.  相似文献   
945.
采用种子乳液聚合法对纳米TiO2进行表面改性,将甲基丙烯酸甲酯包覆在纳米TiO2表面,形成TiO2/PMMA复合粒子。采用FT-IR、XRD、XPS、TEM和激光粒度等分析手段对所得产物的形貌、尺寸、所携带官能团及表面元素变化情况进行了表征。结果表明复合粒子呈现核壳结构,粒子的粒径分布、团聚现象和分散性都得到改善。  相似文献   
946.
Abstract

Temperature-responsive glycopolymer brushes were designed to investigate the effects of grafting architectures of the copolymers on the selective adhesion and collection of hypatocytes. Homo, random and block sequences of N-isopropylacrylamide and 2-lactobionamidoethyl methacrylate were grafted on glass substrates via surface-initiated atom transfer radical polymerization. The galactose/lactose-specific lectin RCA120 and HepG2 cells were used to test for specific recognition of the polymer brushes containing galactose residues over the lower critical solution temperatures (LCSTs). RCA120 showed a specific binding to the brush surfaces at 37 °C. These brush surfaces also facilitated the adhesion of HepG2 cells at 37 °C under nonserum conditions, whereas no adhesion was observed for NIH-3T3 fibroblasts. When the temperature was decreased to 25 °C, almost all the HepG2 cells detached from the block copolymer brush, whereas the random copolymer brush did not release the cells. The difference in releasing kinetics of cells from the surfaces with different grafting architectures can be explained by the correlated effects of significant changes in LCST, mobility, hydrophilicity and mechanical properties of the grafted polymer chains. These findings are important for designing ‘on–off’ cell capture/release substrates for various biomedical applications such as selective cell separation.  相似文献   
947.
Abstract

The grafting of poly(hydroxyethylmethacrylate) on polymeric porous membranes via atom transfer radical polymerization (ATRP) and subsequent modification with a photo-responsive spiropyran derivative is described. This method leads to photo-responsive membranes with desirable properties such as light-controlled permeability changes, exceptional photo-stability and repeatability of the photo-responsive switching. Conventional track etched polyester membranes were first treated with plasma polymer coating introducing anchoring groups, which allowed the attachment of ATRP-initiator molecules on the membrane surface. Surface initiated ARGET–ATRP of hydroxyethylmethacrylate (where ARGET stands for activator regenerated by electron transfer) leads to a membrane covered with a polymer layer, whereas the controlled polymerization procedure allows good control over the thickness of the polymer layer in respect to the polymerization conditions. Therefore, the final permeability of the membranes could be tailored by choice of pore diameter of the initial membranes, applied monomer concentration or polymerization time. Moreover a remarkable switch in permeability (more than 1000%) upon irradiation with UV-light could be achieved. These properties enable possible applications in the field of transdermal drug delivery, filtration, or sensing.  相似文献   
948.
在乙腈溶剂中,以N,N’-亚甲基双丙烯酰胺作交联剂,用蒸馏沉淀聚合法,首次制备了聚丙烯酰胺复合聚合物微球。通过调配丙烯酰胺(AM)和丙烯酸(AA)两种单体的比例和浓度以及交联剂的比例,发现在m(AM)∶m(AA)=1∶1、总单体浓度为25 g/L、交联剂占总单体质量的8%时,聚合物微球形貌及其水化后特性最好。同法还由丙烯酰胺与具不同功能单体共聚,合成具有不同功能特性的二元或三元复合微球。本法操作简单,绿色环保,所得微球粒径均一,单分散性好,在水溶液中自身适度膨胀而又不散团,具有一定弹性,可选择性地进入不同地层孔道,适用于油藏深部调驱以提高采收率。  相似文献   
949.
该研究首次利用功能单体2-乙烯基-4,6-二氨基-1,3,5-三嗪(VDAT)在水相中合成具有生物应用前景的微米级核壳微球。首先,我们利用分散聚合制备出了微米级,单分散,且表面带有足够负电荷的聚苯乙烯微球(PS)模板。再利用半连续无皂乳液聚合法在阳离子引发剂的作用下,于水相中将微溶于热水的单体VDAT引发聚合。通过静电作用将带正电荷的VDAT聚合物(PVDAT)包覆于带负电荷的PS微球表面,成功合成PVDAT@PS功能微球。最后利用该功能微球对不同双链DNA的吸附,初步研究其在生物领域的应用。  相似文献   
950.
不同条件下利用阳离子型表面活性剂十六烷基三甲基溴化铵(CTAB)对粉煤灰漂珠(FAFB)进行有机改性;再以苯胺(An)为单体,十二烷基苯磺酸(DBSA)为乳化剂和掺杂剂,过硫酸铵(APS)为氧化剂,利用乳液聚合法合成了有机改性漂珠/聚苯胺复合材料(FAFB-CTAB/PAn)。利用FTIR、XRD、SEM、TGA、化学元素分析和四探针技术对产物的结构与性能进行分析。结果表明:利用试验方法可得到改性效果最佳的FAFB,其中CTAB浓度为0.20mol/L,在80℃反应90min,以及CTAB改性漂珠(FAFB-CTAB)与聚苯胺(PAn)为原位复合;TGA结果说明PAn的包覆量为9.80%,且随着FAFB-CTAB的引入PAn的耐热性能增强,PAn的分解温度滞后了25℃;利用四探针技术测试发现,随着PAn的包覆,FAFB-CTAB/PAn的电导率可达到0.06S/cm,但仍处于半导体的范围。  相似文献   
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