一种季铵型聚离子液体刷的制备及表征

用表面引发反向原子转移自由基聚合方法RATRP,以CuCl2/Bpy/AIBN为催化体系,在硅片表面成功接枝聚合了一种季铵型离子液体.利用椭圆偏光、静态接触角测定、傅里叶变换衰减红外光谱(ATR-FTIR)、X射线光电子能谱(XPS)、原子力显微镜(AFM)、激光光散射对聚合物分子量、聚合物膜等进行了表征.结果表明,聚合离子液体膜表面的润湿性与离子液体的种类及取代基碳链长度密切相关.     

基于ARGET-ATRP法的硅表面接枝两亲性嵌段聚合物刷的研究

采用电子转移活化再生催化剂原子转移自由基聚合(ARGET-ATRP),在硅片表面接枝了PMMA-b-PHPA-RhB两亲性嵌段共聚物刷.通过红外(FT-IR)、核磁共振(1 HNMR)、凝胶渗透色谱(GPC)、接触角(CA)和原子力显微镜(AFM)对产物进行了表征分析.结果表明,溶液中形成的聚甲基丙烯酸甲酯的数均分子量Mn为23 220,分子量分布为1.24,分子量分布较窄,符合活性自由基聚合的特征;聚合物链活性末端溴的存在证实了聚合过程是按照ARGET-ATRP机理进行,硅片表面已成功接枝了结构可控的PMMA-b-PHPA-RhB嵌段共聚物刷.     

在离子液体中合成淀粉基絮凝剂的研究

以淀粉和丙烯酰胺为原料,在离子液体氯化1-烯丙基-3-甲基咪唑中通过接枝共聚反应合成了丙烯酰胺-淀粉絮凝剂.研究了淀粉在离子液体和水中溶解情况的差异.通过傅立叶变换红外光谱证实了丙烯酰胺与淀粉分子发生了接枝共聚反应.考察了丙烯酰胺与淀粉的质量之比、引发剂用量、反应温度和时间对接枝共聚反应的影响.比较了在离子液体和水中合成得到的絮凝剂在高岭土悬浊液中的絮凝能力.     

聚1-乙烯基-3-氨丙基咪唑四氟硼酸盐离子液体膜增敏检测丁羟基茴香醚

成功合成了1-乙烯基-3-氨丙基咪唑四氟硼酸盐,采用核磁共振氢谱、红外光谱和紫外光谱对其结构进行表征.以1-乙烯基-3-氨丙基咪唑四氟硼酸盐离子液体为功能单体,N,N’-亚甲基双丙烯酰胺为交联剂,过硫酸铵和四甲基乙二胺为引发剂,经自由基引发聚合在玻碳电极表面制备聚离子液体膜修饰电极.采用伏安法研究了丁羟基茴香醚在该聚离子液体膜修饰电极表面的电化学行为.结果表明,聚离子液体膜能增强其电化学响应.在优化条件下,氧化峰峰电流与丁羟基茴香醚浓度在1.0×10~(-8)~1.0×10~(-5)mol/L范围内呈线性关系,检出限为8.8×10~(-9)mol/L(R_(SN)=3).     

磁性纳米复合粒子表面接枝聚苯乙烯磺酸钠的制备

合成了聚苯乙烯磺酸钠接枝Fe3O4/SiO2纳米复合材料.通过表面引发原子转移自由基聚合在Fe3O4/SiO2磁性纳米粒子表面包覆了阴离子聚电解质(聚苯乙烯磺酸钠).利用透射电子显微镜(TEM),傅立叶变换红外光谱仪(FT-IR),震荡磁力计(VSM),X射线能谱仪(EDS),全自动X射线衍射仪(XRD)等仪器对所制备的复合材料进行了表征,成功制备了尺寸均一的聚苯乙烯磺酸钠接枝Fe3O4/SiO2核壳结构的纳米复合材料.     

超亲水纤维素/环糊精基聚电解质刷复合气凝胶的制备及对乳化油分离研究

现代工业生产中会出现大量油滴粒径微小、能够在水体中稳定且长期存在的乳化油,其难以被破乳分离,对土壤、水体有严重危害。本文通过反相悬浮法制备β-环糊精(β-CD)微球,利用原子转移自由基聚合(ATRP)的方法在β-环糊精微球上接枝阳离子聚合物刷聚[甲基丙烯酸(N,N-二甲氨基)乙酯](PDMAEMA),再将纤维素与环糊精基聚电解质刷进行复合制备具有超亲水性/水下超疏油的纤维素/环糊精基聚电解质刷(CE/β-CD-g-PDMAEMA)复合气凝胶。以水包油(O/W)型吐温80(Tween 80)和十二烷基苯磺酸钠(SDBS)乳化油为研究对象,考察了环糊精基聚电解质刷的添加量对乳化油分离效果的影响,实验结果表明:当环糊精基聚电解质刷添加量为5%时,对乳化油的分离效率高达98%,乳化油分离粒径由1μm降至50 nm以下。CE/β-CD-g-PDMAEMA复合气凝胶的制备工艺简单,分离效率高,对于乳化油的破乳分离具有潜在的工业应用价值。     

膜表面嵌段接枝聚合物刷制备离子识别膜

采用原子转移自由基聚合(ATRP)方法,首先在聚对苯二甲酸乙二醇酯(PET)径迹-刻蚀膜表面接枝聚合物N-异丙基丙烯酰胺(NIPAM),然后二次接枝甲基丙烯酸羟乙酯(HEMA),最后用具有离子识别功能的5-胺基-1,10-邻菲罗啉(5-N-1,10-Phen)对HEMA进行封端,制备出具有两嵌段聚合物刷结构的离子识别功能膜。通过傅里叶变换全反射红外光谱(ATR FT-IR)、X-射线电子能谱(XPS)、扫描电子显微镜(SEM)以及接触角测试仪等手段对所制备的膜进行了表征,同时考察了所制备功能膜对溶液中Cu2+的吸附能力。结果表明,通过ATRP方法能够将NIPAM和HEMA链段嵌段接枝在PET膜表面形成聚合物刷,采用的邻菲罗啉能够对HEMA进行封端,且所制备的膜对Cu2+具有吸附作用。     

亲水性聚合物刷通过原子转移自由基聚合以化学键接方式接枝在单晶硅表面（Ⅰ）

实现在Si-H表面用UV辐照将4-氯代乙烯基苯(4-vinylbenzyl chloride,VBC)的单分子层以共价键的方式连接在硅片上形成Si-VBC表面;利用苄基氯引发原子转移自由基聚合(ATRP)反应接枝亲水性2-羟乙基甲基丙烯酸酯(2-hydroxyethyl methacrylate,HEMA)聚合物刷,形成亲水的Si-VBC-g-P(HEMA)表面.用X射线光电子能谱(XPS)表征接枝有亲水聚合物刷硅表面的化学组成,并对其动力学进行研究.     

接枝在六面体和球形表面的聚电解质刷相行为对比研究

采用分子动力学方法模拟了接枝在六面体和球形纳米粒子表面的聚电解质刷．研究了3价抗衡离子条件下，2种形状的聚电解质刷在不良溶剂中的相行为．通过对比三维相图、二维等密度图和刷高，分析讨论了2种刷的状态．结果表明，接枝表面曲率均匀与否，对其上的聚电解质刷相行为有很大影响．计算了聚电解质刷的链间关联函数，同时统计了3价抗衡离子的链内和链间关联作用，定量证明曲率不均匀会增强链间的关联效应，导致2种聚电解质刷的相行为出现差异．      

制备条件对自由基聚合固载酸性离子液体催化性能的影响

利用改性的巯基硅胶与乙烯基咪唑类酸性离子液体发生自由基聚合反应制备固载酸性离子液体催化剂[(CH2)3SO3HVIm]HSO4/硅胶.考察聚合温度、离子液体单体量和聚合反应时间的变化对所制备催化剂催化性能的影响,并用红外光谱(FTIR)、热重/差示扫描量热分析(TG/DSC)等对催化剂进行表征.结果表明:聚合温度60 ℃、每g巯基硅胶载体固载离子液体单体10 mmol、聚合反应时间30h时合成的催化剂催化效果最佳.同时,将最佳条件下制备的催化剂应用于一系列羧酸与醇的酯化反应,酯收率大于87%.     

甜玉米L-11与糯玉米L-70的染色体核型分析

采用常规根尖压片法对甜玉米和糯玉米的染色体标本做核型分析.结果表明: 甜玉米（L-11株系）和糯玉米（L-70株系）的染色体数均为2n＝20,两者均为二倍体.甜玉米核型公式为2n＝2x＝20＝2M﹢12m﹢6sm(2Sat),染色体相对长度系数组成为2L﹢4M2﹢12M1﹢2S,按照Stebbins标准核型分类属于2B核型,不对称系数AS.K%＝59.66%.糯玉米核型公式为2n＝2x＝20＝2M﹢8m(2Sat)﹢10sm,染色体相对长度系数组成为2L﹢8M2﹢6M1﹢4S,分类属于2A核型,不对称系数AS.K%＝60.41%.说明甜玉米（L-11株系）的进化程度较高.     

原子力显微镜对电场诱导组装的酶/聚电解质多层膜表面酶分子聚集拓扑形貌的表征

采用原子力显微镜观察了不同电压下电场诱导组装的酶/聚电解质多层膜表面酶分 子的聚集拓扑形貌, 研究了膜表面粗糙度和表面形貌随操作电压变化的关系以及酶在膜表 面聚集形态的不同对酶活力的响. 实验结果表明, 不同的组装方法对膜表面酶分子的形态 和分布具有很大影响, 在较低的操作电压下, 酶分子以分子簇形式存在, 而在较高操作 电压的作用下, 酶分子在膜表面以聚集体形式存在.     

Synthesis,characterization, and tunable wettability of poly(ionic liquid) brushes via nitroxide-mediated radical polymerization (NMP)

Well-defined poly (ionic liquid) brushes with tunable wettability are successfully synthesized via nitroxide-mediated radical polymerization. X-ray photoelectron spectroscopy, attenuated total reflection infrared spectroscopy and static water contact angle measurements are used to monitor each step. Ellipsometry, nuclear magnetic resonance (1H and 13C) spectra and gel permeation chromatographic measurements reveal that there is a linear increase in polymer film thickness with polymerization time, indicating that chain growth from the surface is a controlled/“living” polymerization. The surface morphology was measured by atomic force microscopy. Moreover, the surfaces of the poly (ionic liquid) brushes with tunable wettability and reversible switching between hydrophilicity and hydrophobicity can be easily achieved by counteranion exchange.     

Preparation of polystyrene/ SiO2 nanocomposites by surface-initiated nitroxidemediated radical polymerization

As nanoscopic science, technology, and engineering have been rapidly developed in recent years, nanomate- rials have attracted widespread attention for their spe- cific capability in the optics, electrics, calorifics, mag- netics, catalysis and mechanics …     

Electrochemical properties and structure of MlNi5-xSnx system

The electrochemical properties and structure of MlNiSnx (x=0-0.5) hydrogen storage alloys were investigated by pressure-composition isotherms, electrochemical measurements, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and atomic parameters. With a small amount of tin substitution, the cycle life increases by 52% (0.5C) and 42% (1.0C), but maximum discharge capacity decreases only by 3.0% and 3.5%, respectively. The cycle life is obviously improved by the low volume expansion and the formed SnO2 surface layers upon electrochemical cycling. The substitution of Ni by Sn leads to an increase of theunit cell volume and charge-discharge cycle life and decrease of the plateau pressure, hysteresis and the hydrogen storage capacity. The standard enthalpy of hydride formation decreases with increasing tin substitution. The main factor that influences the standard enthalpy of the hydriding reaction is the number of the outer orbit electrons and not the atomic size factor.     

Chemical identification of individual surface atoms by atomic force microscopy

Scanning probe microscopy is a versatile and powerful method that uses sharp tips to image, measure and manipulate matter at surfaces with atomic resolution. At cryogenic temperatures, scanning probe microscopy can even provide electron tunnelling spectra that serve as fingerprints of the vibrational properties of adsorbed molecules and of the electronic properties of magnetic impurity atoms, thereby allowing chemical identification. But in many instances, and particularly for insulating systems, determining the exact chemical composition of surfaces or nanostructures remains a considerable challenge. In principle, dynamic force microscopy should make it possible to overcome this problem: it can image insulator, semiconductor and metal surfaces with true atomic resolution, by detecting and precisely measuring the short-range forces that arise with the onset of chemical bonding between the tip and surface atoms and that depend sensitively on the chemical identity of the atoms involved. Here we report precise measurements of such short-range chemical forces, and show that their dependence on the force microscope tip used can be overcome through a normalization procedure. This allows us to use the chemical force measurements as the basis for atomic recognition, even at room temperature. We illustrate the performance of this approach by imaging the surface of a particularly challenging alloy system and successfully identifying the three constituent atomic species silicon, tin and lead, even though these exhibit very similar chemical properties and identical surface position preferences that render any discrimination attempt based on topographic measurements impossible.     

DBD-PECVD法制备高疏水性氟碳聚合物(a-C:F)薄膜的研究

以C4F8为放电气体,利用介质阻挡放电化学气相沉积(DBD-PECVD)法制备了氟碳聚合物(a-C:F)薄膜.使用FTIR、AFM、接触角测量仪、台阶仪对a-C:F薄膜进行了表征,研究了放电压力及沉积时间对a-C:F薄膜的沉积速率、均方根表面粗糙度(RMS)和a-C:F薄膜疏水性的影响.实验结果表明,薄膜的沉积速率随放电压力的升高而增大,最大值为193 nm·min-1;当放电压力较低时,薄膜的RMS值小于1.0 nm;放电压力较高时,薄膜的RMS值大于100 nm.无论是改变放电压力还是沉积时间,a-C:F薄膜均表现出很强的疏水特性,最大接触角(以普通滤纸为基底)可达137°.a-C:F薄膜的表面粗糙度是影响a-C:F薄膜疏水性的重要因素.     

Wafer-scale graphene on 2 inch SiC with uniform structural and electrical characteristics

Wafer-scale graphene on SiC with uniform structural and electrical features is needed to realize graphene-based radio frequency devices and integrated circuits.Here,a continuous bi/trilayer of graphene with uniform structural and electrical features was grown on 2 inch 6H-SiC (0001) by etching before and after graphene growth.Optical and atomic force microscopy images indicate the surface morphology of graphene is uniform over the 2 inch wafer.Raman and transmittance spectra confirmed that its layer number was also uniform.Contactless resistance measurements indicated the average graphene sheet resistance was 720 /with a non-uniformity of 7.2%.Large area contactless mobility measurements gave a carrier mobility of about 450 cm2 /(V s) with an electron concentration of about 1.5×10 13 cm2.To our knowledge,such homogeneous morphology and resistance on wafer scale are among the best results reported for wafer-scale graphene on SiC.     

海洋卫星微波遥感技术发展现状与展望

 主动式和被动式微波遥感可以得到大量的地球物理参数和上层海洋信息,包括海表温度、海面矢量风、海面高度、海表盐度、海冰等。微波遥感可以穿透云层,全天候不间断观测海况信息。中国计划2011年发射运行的“海洋”2号（HY-2A）卫星有效载荷为3个微波遥感器,主要用来观测海面矢量风、海表温度和海面高度。HY-2A卫星将有效提高全球海洋卫星观测在时间和空间上的采样频率。本文介绍了与HY-2A卫星相关的海洋微波遥感技术现状,对微波遥感的优势和目前业务化运行的海洋微波卫星的局限性进行分析,总结了微波遥感的新技术进展和全球下一代微波遥感卫星的发射计划,最后指出发展中国立体海洋监测和中国“海洋”3号（HY-3）卫星（其主载荷为C频段多极化合成孔径雷达）对于更深入了解大洋和海岸带的必要性。