利用Poiseuille方程确定聚乙烯醇在粘度计毛细管管壁上吸附层的厚度

利用高分子溶液流过时间测量之前和之后纯溶剂流过时间的变化不仅再次证实了极低浓度区高分子溶液反常粘度行为的起源和校正方法，而且找到了定量研究粘度计毛细管管壁上高分子吸附层厚度的实验方法。研究结果表明，溶剂的性质对高分子吸附层厚度有着显著影响。     

高分子吸附层分子形貌的理论描述

应用随机过程与概率统计理论, 以随机变量U表示高分子吸附层的厚度, 导出了U的分布密度, 建立起了处理高分子吸附层分子形貌的模型. 结合实验结果, 分析了平均分子量为1.08×106和链电荷密度为0.254的阴离子型聚电解质在黏土颗粒表面吸附层的分子形貌, 给出了吸附层厚度随机性分布的统计规律.     

粘度法研究明胶在聚氨酯弹性体表面的吸附

根据文献以异佛尔酮二异氰酸酯（IPDI）为原料制备了具有较好机械性能的聚氨酯弹性体胶条（PU）,并在胶条表面接枝肝素,得到肝素化聚氨酯胶条（PU-Hep）。将聚氨酯胶条浸泡在明胶稀溶液中,测量溶液粘度随时间、溶液浓度和温度的变化,并采用具有界面校正的粘度方程从实验相对粘度数据计算明胶在聚氨酯表面的吸附量。研究发现明胶分...     

树状高分子溶液在粘度计毛细管表面的吸附现象

本文测定了树状高分子DAB(PA) n 水溶液和脂肪族超支化聚酯及其硅烷化衍生物溶液性质 .通过粘度测量 ,得到了吸附常数k ,半数吸附浓度ca,分子间缔合常数Km ,特性粘度 [η]等参数 ,解释了特性粘度的反常行为 ,重点研究了吸附现象 .发现树状高分子和超支化高分子溶液在粘度计毛细管表面形成了多层吸附 ,高分子之间的相互作用及高分子与溶剂分子间的氢键作用是形成多层吸附的重要原因     

XPS法测量铝箔表面氧化铝的厚度

介绍了一种无需溅射、无需变角，只需一次简单的ＸＰＳ（Ｘ射线光电子能谱）窄扫描，即可根据谱图中氧化态和金属态的相对强度算出铝金属表面氧化铝的厚度。用该法测量了一系列不同方法处理的铝表面氧比铝厚度，并与椭偏法及ＮＲＡ法（核反应分析法）测定结果进行了对比，结果表明，该法是一种简便准确的膜厚测量法。     

聚苯乙烯在石墨表面吸附的分子动力学模拟

采用分子动力学(MD)模拟方法研究了单链聚苯乙烯(PS)在石墨表面的吸附. 模拟结果表明, 吸附后PS在平行于石墨表面的方向可视为准二维椭圆结构, 并且在此方向上的均方回转半径值(R2∥)与其所含单体数目(N)具有指数关系R2∥-N2v, 指数2v约等于1.04; 最后指出PS吸附过程的主要驱动力为PS链段与表面之间的范德华作用力.     

聚氧化乙烯水溶液粘度的测定

测定了不同分子量聚氧化乙烯(PEO)在水溶液中的粘度，发现在低浓度区高分子溶液比浓粘度出现负偏离。用高分子溶液流过时间对浓度作图的外推值t0^*重新计算相对粘度，则高分子溶液比浓粘度与浓度之间满足线性关系。不同分子量PEO水溶液流过时间对浓度作图的外推值t0^*是完全一致的。利用纯溶剂在粘度计中流过时间的改变确定了高分子在毛细管管壁上吸附层的厚度，发现PEO在毛细管管壁上吸附层厚度与分子量无关。     

能量色散X荧光光谱法测定碳钢表面的镀铬层厚度

制作了一组表面具有不同厚度镀铬层的４５碳钢标准块,并应用能量色散Ｘ荧光光谱法（ＥＤＸＲＦ）对镀层厚度进行了测度基数据处理中运用Ｎｅｗｔｏｎ迭代法对工作曲线进行了拟合,结果满意。     

压汞法测量玻璃毛细孔中的水和正癸烷

水在固体表面或在毛细孔玻璃中的性质,一直是人们感兴趣的问题。而靠近固体表面的水,其性质不同于体相(Bulk)水,也是为人所知的事实。已经知道,邻近水的热容、密度、粘度、电导及结构等都不同于体相水。但邻近水的厚度究竟为多少,或者说,这种固体表面对水的性质影响究竟是长程的还是短程的,目前还没有统一的结论。用压汞法测量多孔物质的孔体积,是人们已熟知的方法,但还没有人将其用于测量液体在毛细孔中的体积、密度等行为。我们尝试了用压汞法,测量具有确定孔径的毛细孔玻璃(CPG),在吸附了不同量水后孔体积的变化,进而计算了不同吸附层的水在CPG中的体积、密度。此外还测定了载有不同量正癸烷后,CPG孔体积的变化。     

超临界甲烷在高表面活性炭上的吸附测量及其理论分析

实验测定了0～10 MPa,233～333 K (20 K间隔)范围内超临界甲烷在高表面活性炭上的吸/脱附等温线,确定了此物理吸附过程的可逆性,并从实验数据计算出吸附热为16.5 kJ/mol.　建立了描述具有最大点的吸附等温线模型,其总体偏差为±2%.　模型保持了特征吸附能恒定的性质,方程指数亦反映了吸附剂的微孔分布特征,模型参数给出了超临界甲烷的吸附相密度.　将超临界吸附极限态引入等温线模型中,经典的吸附理论亦可解释超临界吸附现象.     

2D Diffusion of Macromolecules Adsorbed on Glass Microspheres

Summary: It has been demonstrated that diffusion of polycation adsorbed on glass microspheres occurs without desorption of the macromolecules into the solution and, therefore, can be characterizerd as 2D-diffusion. The diffusion coefficint is estimated to be 1.4 × 10⁻¹² cm²/s.     

Effect of the Cathode Catalyst Layer Thickness on the Performance in Direct Methanol Fuel Cells

Catalyst deposition control is one of the overlooked areas of fuel cell fabrication and research that can affect the overall performance and cost of the fuel cell to manufacture for mass production. The effect of the different individual catalyst layer thicknesses and loadings of the cathode compartment of a direct methanol fuel cell (DMFC) was investigated. The drawdown method was performed at thicknesses varying from 1 mil to 8 mils with platinum loadings ranging from 0.25 mg cm^?2 to 2.0 mg cm^?2. The membrane electrode assemblies (MEAs) with thicker individual layers (8 mil and 4 mil) performed better overall compared to the ones prepared with thinner individual layers (1 mil). The power density maxima for the different loading levels followed an exponential decrease of platinum utilization at the higher loading levels. The painted MEAs tended to display the similar performance characteristics as the drawdown MEA layers closest to the thickness at the respective loadings.     

Motion of a Colloidal Sphere Covered by a Layer of Adsorbed Polymers Normal to a Plane Surface

A combined analytical–numerical study is presented for the slow motion of a spherical particle coated with a layer of adsorbed polymers perpendicular to an infinite plane, which can be either a solid wall or a free surface. The Reynolds number is assumed to be vanishingly small, and the thickness of the surface polymer layer is assumed to be much smaller than the particle radius and the spacing between the particle and the plane boundary. A method of matched asymptotic expansions in a small parameter λ incorporated with a boundary collocation technique is used to solve the creeping flow equations inside and outside the adsorbed polymer layer, where λ is the ratio of the characteristic thickness of the polymer layer to the particle radius. The results for the hydrodynamic force exerted on the particle in a resistance problem and for the particle velocity in a mobility problem are expressed in terms of the effective hydrodynamic thickness (L) of the polymer layer, which is accurate to O(λ²). The O(λ) term forLnormalized by its value in the absence of the plane boundary is found to be independent of the polymer segment distribution and the volume fraction of the segments. The O(λ²) term forL, however, is a sensitive function of the polymer segment distribution and the volume fraction of the segments. In general, the boundary effects on the motion of a polymer-coated particle can be quite significant.     

苯三偶氮衍生物吸附在银溶液上的SERRS谱

In this paper, the SERRS of BATD has been investigated, the effect of pH, concentration and electrolyte on SERRS was discussed and the adsorbed state of BTAD was figured. We suggest that the adsorbed state of BTAD is the bonding of benzotriazol to Ag surface via lone pair electron on the nitrogen. With HCl and ascorbic acid aggregate Ag sol, the dependence of SERRS on BTAD concentration behaves differently. In the former case, the adsorbed state changes, but in the latter it remains the same. Small amount of electrolyte will induce the active sites on the surface, but when it is more than 1×10-2mol﹒L-1, the competent adsorbtion reduces the Raman scattering intensity. Hydrogen ions protonize BTAD to BTAHD and reduce the contribution of lone pair electron on N atom of the conjugated system.     

超细氮碳化物中吸附氧和化合氧的测定

用跟踪式程序升温、红外检测和微机解卷技术，测定氮碳化物超细粉的吸附氧和化合氧，探讨了超细Ｓｉ３Ｎ４，ＡＩＮ，ＴｉＣＮ和ＳｉＣ中不同状态氧量与其制备方法，颗粒度及放置时间的关系。     

吸附中间物表面扩散对Pt/Nafion体系氢析出反应影响初步研究

实验表明 ,铂黑粉末 /Nafion复合微电极的析氢超电势比同样面积的平面铂复合微电极为低 .这是由于Nafion膜与平面铂电极或者铂黑粉末形成的Pt/Nation界面之外还存在可供反应中间物扩散及进行复合反应的自由铂表面 ,这些扩散和复合反应降低了Pt/Nafion界面上电化学反应中间物浓度 ,从而降低了氢超电势 ,加速了析氢反应的速度 .     

输运层厚度对双层有机器件复合发光的影响

采用ITO/PVK/Alq/Al双层电致发光(EL)结构,制备了三种载流子输运层厚度分别为30、 60、 120 nm,发光层厚度均为300 nm的有机薄膜EL器件,测试其EL谱及J-V特性曲线.根据有机EL器件中载流子的产生和输运过程导出了载流子复合几率及电子和空穴密度分布表示式,用以解释其发光强度随输运层厚度的变化关系,用一维无序结构载流子随机跃迁模型讨论输运层厚度对器件电流密度及启动电压的影响,探讨了载流子在薄膜中的输运过程,其理论与实验符合得很好.     

原位聚合法制备多孔高聚物PLOT柱涂层厚度的计算公式

讨论了原位聚合法制备有机多孔高聚物ＰＬＯＴ柱中毛细管半径ｒ,反应液浓度Ｃ及涂层厚度ｄ＿ｓ的关系,并通过实验建立了一个计算涂层厚度ｄ＿ｓ的经验公式。     

A Surface Masking Technique for the Determination of Plasma Polymer Film Thickness by AFM

A method for the determination of coating film thicknesses at nanometer resolution based on surface masking and atomic force microscopy (AFM) is described. A polymeric mask is used to cover part of a substrate during the deposition of thin polymeric coatings by plasma polymerization, allowing the production of well defined polymer steps of heights of a few tens of nanometers. Tapping mode AFM has been employed to analyze the topography of these steps at high resolution. This method has also allowed accurate measurement of the kinetics of the deposition of plasma polymer films over a range of exposure times. XPS analysis of different substrate surfaces following mask removal found barely detectable residues, suggesting that the underlying surface chemistry remains unchanged, and accessible for further modification. In combination with quartz crystal microgravimetry, the method has been applied to the measurement of the density of plasma polymer coatings in the thickness range 4–50 nm.