煤孔结构特性对水煤浆性质的影响分析

通过三种不同的方法(CO2吸附法、N2吸附法和压汞法)测试了不同变质程度煤的孔结构性质，分析了煤的孔结构特性与水煤浆性质之间的关系。结果表明，煤的孔结构特性对水煤浆性质的影响较为复杂，主要是煤的大孔结构对煤浆成浆性的影响。在相近的孔体积和孔径分布下，煤的成浆性差别较大。孔结构特性本身作为一个独立的因素不能完全体现出对水煤浆性质的影响程度，与煤的表面性质如含氧官能团性质、煤表面的疏水性以及煤的吸水性等密切相关，共同影响着水煤浆的性质。     

压汞法研究大孔离子交换树脂和大孔吸附树脂的孔结构 Ⅵ.汞的滞后与孔结构的关系

压汞过程中汞滞后体积早已为人们发现,当压力还原时,孔内依然保留部分汞,汞滞后体积依赖于多孔材料(例如大孔离子交换树脂大孔吸附树脂或分子筛等)的孔结构。     

压汞法研究大孔离子交换树脂和大孔吸附树脂的孔结构.Ⅴ.汞接触角和表面张力对孔结构的影响

利用压汞法测定多孔体孔径大小及孔分布已是众所周知,而且得到广泛应用。一般情况下,压汞法最常用的是园柱孔模型。实际上,大孔离子交换树脂和大孔吸附树脂的孔道是呈异形孔,表面各处并不均匀。因此,汞与树脂表面的接触角和表面张力是和树脂的孔结构直接相关。     

碘原子在银(110)面吸附的能带理论研究

采用基于密度泛函理论的第一性模守恒赝势平面波分子动力学方法研究了碘原子在Ag(110)面的吸附性质。首先对银体相性质和Ag(110)面的驰豫进行了计算,验证了生成的赝势的可靠性;随后对碘原子在Ag(110)表面各吸附位的性质进行了研究,最稳定的吸附位是短桥位。另外,本文还考虑了碘原子吸附对Ag(110)表面结构性质的影响。     

颗粒聚集体对两性SiO2颗粒无水泡沫表面性质的影响

基于Pickering乳液模板法, 合成了2种用于制备非水泡沫的不同相对两亲面积的Janus颗粒, 并合成了表面均匀修饰的颗粒作为对比. 通过调整油混合物的性质, 对颗粒在油气表面上的行为进行了测量和对比, 对颗粒团聚体在颗粒吸附中的作用进行了研究. 结果表明, 受颗粒表面接触角的影响, Janus颗粒的表面活性(表面张力降低能力与产生泡沫的体积)不总是大于均匀改性颗粒. 均匀改性颗粒和Janus颗粒均不是以单个颗粒形式从体相吸附至表面上, 而是以颗粒团聚体状态向表面移动, 并且需要颗粒团聚体的Cassie-Baxter复合表面的接触角约为90°, 而颗粒的本征接触角小于70.1°.     

溶剂浸渍树脂孔结构的研究

用萃取剂N_(235)浸渍大孔苯乙烯—二乙烯苯(MSD)树脂制得了溶剂浸渍树脂。用压汞仪测定了溶剂浸渍树脂的孔体积、孔表面积和孔径等,用扫描电镜观察了溶剂浸渍树脂的形貌。MSD树脂对N_(235)吸附率随该树脂的交联度和混合致孔剂用量增加而增加。由于N_(235)分布于MSD树脂孔表面,浸渍树脂的孔体积、孔表面和孔径比MSD树脂显著下降。在孔径1～100nm孔表面吸附N_(235)量最大。低交联度MSD树脂对N_(235)吸附量低,且分布不均匀。     

压汞法研究大孔离子交换树脂和大孔吸附树脂的孔结构.V.汞接触角和表面张力

利用压汞法测定多孔径大小及孔分布已是众所周知，而且得到广泛应用。一般情况下，压汞法最常用的是园柱孔模型，实际上，大孔离子交换树脂和大孔吸附树脂的孔道是呈异形孔，表面各处并不均匀。因此，汞与树脂表达的接触角和表面张力是和树脂和孔结构直接相关。     

多孔炭物理化学结构及其表征

以碳为基本骨架的多孔炭因具有丰富的孔隙结构和表面化学宫能团,在吸附分离、催化、电子等领域应用广泛.在阐述多孔炭孔结构（物理结构）和表面化学宫能团（化学结构）基础上,重点介绍了透射电镜等可直接观察多孔炭孔结构的表征方法及Dubinin微孔充填理论、平均场密度泛函理论、吸附法、压汞法等表征多孔炭孔结构的主要理论及方法,以及...     

各种孔结构活性炭吸附苯、环己烷、正戊烷和正己烷的~1H和~(13)C NMR研究

~1H和~(13)C NMR研究证明被吸附在不同孔结构活性炭中的烃类以毛细管凝聚和吸附在固体表面两种状态存在。链状烷烃平铺地吸附在固体表面。被吸附烃与活性炭表面酸性基团的质子交换在弛豫过程中起着重要作用。     

溶剂对苯乙烯型吸附树脂孔结构的影响

孔结构是苯乙烯型吸附树脂(以下简称吸附树脂)特征之一。溶剂对吸附树脂孔结构有影响,但并不一致,为此选择一系列溶度参数(δ_s)的溶剂,如水、乙醇、苯等,处理吸附树脂,用吸附法、压汞法、比重法及扫描电镜等方法研究其孔结构。研究取得影响的规律性,若吸附树脂溶度参数为δR,干态树脂的孔参数(如比表面积、孔体积、孔隙率等)随|ρS-ρR|值的增加而增大;并取得吸附树脂的处理方法,以良溶剂溶胀,再用水取代为最佳。     

Thermal Analysis of Adsorbed Poly(methyl methacrylate) on Silica

Modulated differential scanning calorimetry has been used to quantify the glass transitions of small adsorbed amounts of poly(methyl methacrylate) (PMMA) on silica. While a relatively narrow, single glass transition was found for bulk PMMA, broader two-component transitions were found for the adsorbed polymer. A two-state model based on loosely bound polymer (glass transition similar to bulk) and more tightly bound polymer (glass transition centered around 156 degrees C) was used to interpret the thermograms. On the basis of this model, the amount of tightly bound polymer was found to be approximately 1.3 mg/m2, corresponding to a 1.1 nm thick layer. The change in heat capacity for the tightly bound polymer at the glass transition temperature was estimated to be about 16% of that of the bulk polymer.     

Effect of pore size on adsorption of a polyelectrolyte to porous glass

The adsorption of quaternized poly(vinylpyridine) (QPVP) on controlled pore glass (CPG) size, over the ionic strength range 0.001-0.5 M was found to display nonmonotonic behavior as a function of pore size. Both adsorption kinetics and ionic strength effects deviated dramatically from behavior typical of adsorption on flat surfaces when the ratio of the pore radius Rp to the polymer hydrodynamic radius Rh became smaller than ca. 2. Ionic strength enhancement of adsorption for small pore sizes was observed at much higher salt concentrations than is typical for polycation adsorption on flat surfaces. The amount of polymer adsorbed per unit surface area of glass GammaA, in 0.5 M NaCl, exhibited a shallow maximum at Rp/Rh approximately 5. Since the value of GammaA for small pore size CPG is strongly depressed by the large surface area, an alternative and more interesting observation is that the amount of polymer adsorbed per gram of CPG, Gammaw, displays a strong maximum when Rp is equal to or slightly smaller than Rh. The efficiency with which QPVP binds anionic micelles to (negatively charged) CPG (grams of surfactant/grams of QPVP) increases strongly with diminishing pore size, indicating that the configuration of polycation bound to small pores favors micelle binding. Since the micelles are larger than small pores, the results indicate that when Rp < Rh, adsorbed polycation molecules reside only partially within the pore. The results of this study are supported by simulations of polyelectrolytes within cylindrical cavities.     

Confinement effect on the adsorption from a binary liquid system near liquid/liquid phase separation

The preferential adsorption of one component of a binary system at the inner surfaces of mesoporous silica glasses was studied in a wide composition range at temperatures close to liquid/liquid phase separation. Confinement effects on the adsorption were investigated by using three controlled-pore glass (CPG-10) materials of different mean pore size (10 to 50 nm). For the experimental system (2-butoxyethanol+water), which exhibits an upper miscibility gap, strong preferential adsorption of water occurs, as the coexistence curve is approached at bulk compositions, at which water is the minority component. In this strong adsorption regime the area-related surface excess amount of adsorbed water decreases with decreasing pore width, while the shift in the volume-related mean composition of the pore liquid shows an opposite trend, i.e., greatest deviation from bulk composition occurring in the most narrow pores. A simple mean-field lattice model of a liquid mixture confined by parallel walls is adopted to rationalize these experimental findings. This model reproduces the main findings of the confinement effect on the adsorption near liquid/liquid phase separation.     

Adsorption of cationic cellulose derivative/anionic surfactant complexes onto solid surfaces. II. Hydrophobized silica surfaces

The effect of the anionic surfactant SDS (sodium dodecyl sulfate) on the adsorption behavior of cationic hydroxyethyl cellulose (Polymer JR-400) and hydrophobically modified cationic cellulose (Quatrisoft LM-200) at hydrophobized silica has been investigated by null ellipsometry and compared with the previous data for adsorption onto hydrophilic silica surfaces. The adsorbed amount of LM-200 is found to be considerably larger than the adsorbed amount of JR-400 at both surfaces. Both polymers had higher affinity toward hydrophobized silica than to silica. The effect of SDS on polymer adsorption was studied under two different conditions: adsorption of polymer/SDS complexes from premixed solutions and addition of SDS to preadsorbed polymer layers. Association of the surfactant to the polymer seems to control the interfacial behavior, which depends on the surfactant concentration. For the JR-400/SDS complex, the adsorbed amount on hydrophobized silica started to increase progressively from much lower SDS concentrations, while the adsorbed amount on silica increased sharply only slightly below the phase separation region. For the LM-200/SDS complex, the adsorbed amounts increased progressively from very low SDS concentrations at both surfaces, and no large difference in the adsorption behavior was observed between two surfaces below the phase separation region. The complex desorbed from the surface at high SDS concentrations above the critical micelle concentration. The reversibility of the adsorption of polymer/SDS complexes upon rinsing was also investigated. When the premixed polymer/SDS solutions at high SDS concentrations (>5 mM) were diluted by adding water, the adsorbed amount increased due to the precipitation of the complex. The effect of the rinsing process on the adsorbed layer was determined by the hydrophobicity of the polymer and the surface.     

Coadsorption and surface forces for selective surfaces in contact with aqueous mixtures of oppositely charged surfactants and low charge density polyelectrolytes

The coadsorption of a positively charged polyelectrolyte (with 10% of the segments carrying a permanent positive charge, AM-MAPTAC-10) and an anionic surfactant (sodium dodecyl sulfate, SDS) on silica and glass surfaces has been investigated using optical reflectometry and a noninterferometric surface force technique. This is a selective coadsorption system in the sense that the polyelectrolyte does adsorb to the surface in the absence of surfactant, whereas the surfactant does not adsorb in the absence ofpolyelectrolyte. It is found that the total adsorbed amount goes through a maximum when the SDS concentration is increased. Maximum adsorption is found when the polyelectrolyte/surfactant complexes formed in bulk solution are close to the charge neutralization point. Some adsorption does occur also when SDS is present in significant excess. The force measured between AM-MAPTAC-10-coated surfaces on approach in the absence of SDS is dominated at long range by an electrostatic double-layer force. Yet, layers formed by coadsorption from solutions containing both polyelectrolyte and surfactant generate long-range forces of an electrosteric nature. On separation, adhesive interactions are found only when the adsorbed amount is low, i.e., in the absence of SDS and in a large excess of SDS. The final state of the adsorbed layer is found to be nonhysteretic, i.e., independent of the history of the system. The conditions for formation of long-lived trapped adsorption states from mixed polymer-surfactant solutions are discussed.     

The adsorption of lysozymes: A model system

Hen egg white lysozyme was adsorbed onto clean borosilicate glass and n-pentyl silane-treated glass surfaces. Both modified (reductively methylated) and native lysozyme were studied. Variable angle X-ray photoelectron spectroscopy (VA-XPS) suggested differences in the nature of the adsorbed layer depending on substrate properties, as well as on degree of methylation of the protein. Adsorbed film thickness (as measured in the dehydrated state by XPS) ranged from 14 Å on hydrophilic glass to 25 Å on the hydrophobic surface. Degree of surface coverage ranged from 45% on the hydrophobic to 69% on the hydrophilic surface. The results suggest that lysozyme unfolds to a greater extent and covers more surface on the hydrophilic glass, possibly due to strong electrostatic interactions at the pH 7.4 conditions used in the study. An analysis of the surface structure of native hen lysozyme by molecular graphics has also been performed, suggesting that adsorption on hydrophobic surfaces should occur via the hydrophobic patch opposite the enzyme active site cleft. A comparison with human lysozyme has also been made using total internal reflection fluorescence (TIRF) spectroscopy to measure protein adsorption on model surfaces. The two proteins have significantly different interfacial properties.     

Non-equilibrium adsorption at solid/liquid interfaces from polyelectrolyte solutions

The poly(2-vinylpyridine) layer was established at the Pyrex glass/water interface with periodic phases of adsorption/desorption runs observed over several days. This was evidenced by determining the concentration of radio-labelled molecules in the solution equilibrating the glass beads as a function of time (the effluent) while the same radio-labelled polymer was slowly supplied by injecting the polymer solution into the reactor containing the adsorbent at a controlled extremely slow rate. Although the adsorption (or the desorption) steps seemed to present some periodic character, they were better correlated with the successive bulk concentration thresholds that were established with time when the initial surface was free of polymer at time zero. Even when the adsorbent was coated at different degrees, desorption steps were correlated to the overstepping of decreasing concentration thresholds. Adsorption and desorption runs were attributed to the existence of different typical interfacial conformations of the adsorbed macromolecules that only can be stabilised in the adsorbed state when the layer was equilibrated with the polymer solution of a certain concentration. Macromolecule were definitely adsorbed when the reconformation process led to a flat conformation (trains). Macromolecules adsorbed with a conformation close to their solution conformation may be desorbed as a result of the reconformation process affecting previously adsorbed neighbour molecules (in the case of partially coated surfaces at time zero of injection). Macromolecules with loops and tails were retained on the surface when the polymer concentration in the bulk was progressively increased (for uncoated surfaces at time zero of injection). All these effect were attributed to the combined influence of topological effects on adsorption and reconformation of adsorbed macromolecules that characterise the non-equilibrium adsorption processes.     

Adsorption and activity of Thermomyces lanuginosus lipase on hydrophobic and hydrophilic surfaces measured with dual polarization interferometry (DPI) and confocal microscopy

The adsorption and activity of Thermomyces lanuginosus lipase (TLL) was measured with dual polarization interferometry (DPI) and confocal microscopy at a hydrophilic and hydrophobic surface. In the adsorption isotherms, it was evident that TLL both had higher affinity for the hydrophobic surface and adsorbed to a higher adsorbed amount (1.90 mg/m²) compared to the hydrophilic surface (1.40–1.50 mg/m²). The thickness of the adsorbed layer was constant (3.5 nm) on both surfaces at an adsorbed amount >1.0 mg/m², but decreased on the hydrophilic surface at lower surface coverage, which might be explained by partially unfolding of the TLL structure. However, a linear dependence of the refractive index of the adsorbed layer on adsorbed amount of TLL on C18 surfaces indicated that the structure of TLL was similar at low and high surface coverage. The activity of adsorbed TLL was measured towards carboxyfluorescein diacetate (CFDA) in solution, which upon lipase activity formed a fluorescent product. The surface fluorescence intensity increase was measured in a confocal microscope as a function of time after lipase adsorption. It was evident that TLL was more active on the hydrophilic surface, which suggested that a larger fraction of adsorbed TLL molecules were oriented with the active site facing the solution compared to the hydrophobic surface. Moreover, most of the activity remained when the TLL surface coverage decreased. Earlier reports on TLL surface mobility on the same surfaces have found that the lateral diffusion was highest on hydrophilic surfaces and at low surface coverage of TLL. Hence, a high lateral mobility might lead to a longer exposure time of the active site towards solution, thereby increasing the activity against a water-soluble substrate.     

Probing molecular-level surface structures of polyethersulfone/pluronic F127 blends using sum-frequency generation vibrational spectroscopy

We blended Pluronic F127 into polyethersulfone (PES) to improve surface properties of PES, which has been extensively used in biomaterial and other applications. The molecular surface structures of PES/Pluronic F127 blends have been investigated by sum-frequency generation (SFG) vibrational spectroscopy. The molecular orientation of surface functional groups of PES changed significantly when blended with a small amount of Pluornic F127. Pluronic F127 on the blend surface also exhibited different features upon contacting with water. The entanglement of PES chains with Pluronic F127 molecules rendered the blends with long-term surface stability in water in contrast to the situation where a layer of Pluronic F127 adsorbed on the PES surface. Atomic force microscopy (AFM) and quartz crystal microbalance (QCM) measurements were included to determine the relative amount of protein that adsorbed to the blend surfaces. The results showed a decreased protein adsorption amount with increasing Pluronic F127 bulk concentration. The correlations between polymer surface properties and detailed molecular structures obtained by SFG would provide insight into the designing and developing of biomedical polymers and functional membranes with improved fouling-resistant properties.     

Poly(vinylpyrrolidone-b-styrene) block copolymers tethered surfaces for protein adsorption and cell adhesion regulation

Poly(vinylpyrrolidone-b-styrene) (PVP-b-PS) diblock copolymers tethered to glass surfaces were prepared, and the effects on protein adsorption and cellular behavior to the glass and the modified glass surfaces investigated. The PVP-b-PS grafting process was confirmed by water contact angle and XPS measurements. The results obtained for the water contact angles suggest that there are two phases that coexist on the PVP-b-PS block copolymer tethered surface, under aqueous conditions. Although the PVP-b-PS surface possessed, to some extent, a protein resistant property, following introduction of the PS segment to the end of tethered PVP, both fibrinogen and lysozyme adsorption were increased significantly. The PVP-b-PS modified surface, based on Western-blot analysis, appeared to have the greatest amount of surface bound vitronectin, however the conformation of the adsorbed vitronectin may have subsequently been affected by the surface tethered copolymer as was suggested by cell culture results. From these results, we proposed that protein adsorption and cell adhesion can be regulated by tuning the chemical compositions of diblock copolymers tethered to surfaces.