等离子体处理云母粉对其表面特性及对其与聚合物界面特性的影响

采用等离子体方法处理填料及增强体表面,是提高填料及增强体与聚合物基体的粘合性、改善复合材料性能的一个新的有效途径。目前研究工作集中于处理条件与复合体系宏观性能的关系上,对处理前后填料表面性质以及填料与聚合物界而性质变化的探讨却很少。而只有了解上述变化才能从本质上认识处理条件与复合体系宏观性能的关系。本文首次对云母粉进行丁醛等离子体处理,测定了处理前后液体在云母粉表面的接触角,估算了处理条件     

多孔硅制备条件对其电致发光特性的影响

应用蒸镀-阳极氧化法制备结构为ITO/PS/p-S i/A l的多孔硅电致发光器件,在7.5V电压下实现了数小时连续电致发光.实验表明,多孔硅电致发光峰位会随着阳极氧化电流密度的增大、腐蚀时间的延长以及HF酸浓度的降低而蓝移.欲制备工作电压较低、发光时间较长、发光效率较高的电致发光样品,则多孔硅制备时的阳极氧化应使用较低电流密度和较短的腐蚀时间.     

生物质焦制备条件对其燃烧反应特性的影响

在热重分析仪上,研究了生物质焦的制备条件对其燃烧反应特性的影响。生物质焦由闪速裂解技术制得,裂解温度为 748 K、773 K和823 K;原料含水质量分数为0、7.0%和11.3%。研究发现,生物质焦中挥发性物质的质量分数和H/C质量比随裂解温度的增加而降低,其燃烧反应性随裂解温度的增加而降低;与高裂解温度条件下制得的生物质焦相比,低裂解温度条件下制得的生物质焦具有较高的反应活化能和对燃烧温度更敏感。原料含水量对生物质焦的燃烧反应特性影响很小;但对高裂解温度条件下制得的生物质焦中的挥发性组分含量有较大的影响。简化的生物质焦本征燃烧反应幂函数动力学模型可以很好地描述其燃烧行为。     

丁醛等离子体处理云母粉对其表面特性及与聚合物界面特性的影响

用电容耦合式等离子体聚合方法对云母粉进行丁醛等离子体处理,通过测定各种液体对密堆积云母粉的渗透速度,确定了液体在云母粉表面的接触角,估算了云母粉的表面张力及与典型线形聚合物的界面张力。结果表明,极性液体在云母粉表面的浸润性因处理而削弱,非极性液体的浸润性基本来变;云母粉表面张力由处理前的41.34(N·m~(-1)·10~(-3))下降到处理5min时的31.51和处理30min时的25.59(N·m~(-1)·10~(-3));处理对云母粉与线形聚合物界面张力的影响因聚合物而不同,但该界面张力的极性分量均因处理而减小。     

污泥水分含量对其空气气化特性的影响(英文)

利用外热式下吸固定床气化实验装置,研究了在一定的空气流量(0.05 m3/h)、气化温度(800℃)下污泥水分含量对3种不同性质污泥空气气化特性的影响。结果表明,气化气中CO2、CH4和H2含量、气化气热值以及水相生成量均随污泥水分含量的增加而增加,而CO含量和焦油生成量呈降低趋势。污泥厌氧消化使气化气中CO、CH4、H2、CmHn含量以及气化气品质降低;而污水处理工艺中的厌氧过程可改善气化气品质,其中来自A2/O工艺消化污泥的气化气品质高于普通活性污泥法消化污泥的气化气品质。随着污泥水分含量的增加,2种不同污水处理工艺产生的消化污泥气化气中CO、CO2和H2含量的差距逐渐加大,来自于同一A2/O工艺的消化与未消化污泥气化气中H2和CO2含量的差距亦逐渐加大,而消化与未消化污泥气化气中CO含量的差距则逐渐接近。     

麻黄碱印迹聚合物合成条件对其形态及结合特性的影响

印迹聚合物合成条件对聚合物性能的影响是分子印迹技术中的一项重要研究内容。以左旋麻黄碱为印迹分子,甲基丙烯酸为功能单体,使用不同的交联剂和致孔剂合成了印迹聚合物,并对所得到的印迹聚合物的比表面积、孔结构和结合特性进行了评价。研究结果说明合成的印迹聚合物对印迹分子具有很好的亲和能力及选择性。致孔剂可以影响聚合物比表面积的大小及单体组成。氯仿是甲基丙烯酸-乙二醇二甲基丙烯酸酯和甲基丙烯酸-季戊四醇三丙烯酸酯聚合链的良溶剂,导致了比表面积及孔容较小的聚合物结构;而以乙腈为致孔剂得到的聚合物有较大的比表面积。共聚物中羧基含量的测定结果也说明,在预聚溶液中单体浓度相同的条件下,以不同的致孔剂进行合成得到的聚合物中甲基丙烯酸的比例不同。聚合物的比表面积及单体浓度的差别都可能导致聚合物的结合容量不同。     

荧光素钠溶液的pH值对其激光及光谱特性的影响

本文研究了荧光素钠乙醇溶液的pH值对其激光能量转换效率以及吸收光谱、荧光光谱等特性的影响。通过对其吸收光谱的研究, 证明荧光素钠在乙醇溶液中存在多种互变异构体。在不同pH值的溶液中, 它们具有不同的浓度而处于酸碱平衡。各种异构体对λ=337.1 nm激发光的吸收截面σ_P和其荧光最子产额φ各不相同。随着pH值的增大, 溶液中双价阴离子的浓度逐渐增大。而双价阴离子的σ_P和φ值为最大。由于激光输出能量的大小与σ_P和φ直接有关, 因此, 荧光素钠溶液的激光能量转换效率也将随着pH值的增大而提高。     

ZnO纳米粒子自建场的形成及对其光电特性的影响

The effect of built-in field on the surface photovoltage(SPV) response of ZnO nanoparticles was investigated by means of surface photovoltage spectroscopy(SPS). From the results of in situ SPS in atmosphere and in vacuum, we suggest that the built-in field should be a main condition for producing SPV response. By comparison of SPS with PL in vacuum as well as in atmosphere, we deduce that by changing the ambience of ZnO, its functional properties can be modulated.     

卡拉胶的特性与其在食品工业中的应用

本文介绍了卡拉胶的结构、生产工艺、理化性质、食品工业应用及开发前景.     

氧化铽团簇的表面修饰及对其荧光特性影响的研究

采用脉冲激光轰击浸于流动相中的氧化铽固体靶，考察了流动相及其流速、脉冲激光输出功率、修饰剂、添加修饰剂顺序等对所获得的氧化铽有机溶胶荧光性能的影响。UV-Vis和荧光光谱的测试表明：以含有修饰剂的无水乙醇作为流动相，可得到良好荧光性能的氧化铽乙醇溶胶，而环己酮与醋酸乙酯均不适合作为该体系的流动相;最佳流速为0.15 mL·s^-1；脉冲激光输出功率大有利于其荧光性能；最佳修饰剂为乙酰丙酮(acac)和2，2′-联吡啶(2，2′-bipy)，且应原位修饰。     

Effects of simulated acid rain on the surface tension of selected leaves

In this study the effect of simulated acid rain on the surface tension of leaves of selected crop plants is reported. The contact angle measurements of liquids (water and n-propanol mixtures) on various plant leaves (bean, mustard, lettuce, cress) showed that the acid rain effect can be investigated when analyses of the surface tension of leaves are estimated. Acid rain was found to give rise to a change in the polar surface tension of leaves, while the apolar surface tension was unaffected. This effect was strongest in bean leaves, which suggests that this is related to the polar surface tension of leaves.     

以全氟丁基为基础的具有高表面活性的氟表面活性剂

氟表面活性剂的环境和生物降解问题是最近的热点, 特别是全氟长链(≥C8)氟表面活性剂的应用限制乃至禁用已成为必然趋势. 本文合成了一种以短链的全氟丁基为基础的阳离子氟表面活性剂, N-[3-(二甲基胺基)丙基]全氟丁基磺酰胺盐酸盐(C4F9SO2NH(CH2)3NH(CH3)+2Cl-, 简称为PFB-MC). 该表面活性剂适用于强酸性环境, 具有极高的表面活性, 其溶液最低表面张力(19.80 mN·m-1)和通常的氟表面活性剂相当. 通过表面张力方法得到了固定pH(pH=2.6-2.7)情况下PFB-MC的表面张力-浓度对数(γ-lgc)曲线, 以及该pH下外加盐([NaCl]=0.1 mol·L-1)对表面张力的影响; 并进一步研究了pH对PFB-MC在其临界胶束浓度(cmc)前后的表面张力的影响.     

What causes extended layering of ionic liquids on the mica surface?

Extended layering of ionic liquids (ILs) on the mica surface has been reported by several groups previously and it is generally accepted that the electrostatic interaction at the IL/mica interface is critical to the observed extended layering. Here we report that, indeed, water adsorption on the mica surface is the key to the extended layering of ionic liquids. The atomic force microscopy (AFM), attenuated total reflectance-fourier transform infrared spectroscopy (ATR-FTIR) and contact angle (CA) results show that ionic liquids form extended layering on a mica surface under ambient conditions when water is adsorbed on the mica surface under such conditions. However, when airborne hydrocarbon contaminants replace the water on the mica surface at the elevated temperatures, instead of layering, ionic liquids exhibit droplet structure, i.e., dewetting. Based on the experimental results, we propose that water enables ion exchange between K+ and the cations of ILs on the mica surface and thus triggers the ordered packing of cations/anions in ILs, resulting in extended layering.     

Recent progress in the determination of solid surface tensions from contact angles

Advancing contact angles of different liquids measured on the same solid surface fall very close to a smooth curve when plotted as a function of liquid surface tension, i.e., gamma(lv)costheta versus gamma(lv). Changing the solid surface, and hence gamma(sv), shifts the curve in a regular manner. These patterns suggest that gamma(lv)costheta depends only on gamma(lv) and gamma(sv). Thus, an "equation of state for the interfacial tensions" was developed to facilitate the determination of solid surface tensions from contact angles in conjunction with Young's equation. However, a close examination of the smooth curves showed that contact angles typically show a scatter of 1-3 degrees around the curves. The existence of the deviations introduces an element of uncertainty in the determination of solid surface tensions. Establishing that (i) contact angles are exclusively a material property of the coating polymer and do not depend on experimental procedures and that (ii) contact angle measurements with a sophisticated methodology, axisymmetric drop shape analysis (ADSA), are highly reproducible guarantees that the deviations are not experimental errors and must have physical causes. The contact angles of a large number of liquids on the films of four different fluoropolymers were studied to identify the causes of the deviations. Specific molecular interactions at solid-vapor and/or solid-liquid interfaces account for the minor contact angle deviations. Such interactions take place in different ways. Adsorption of vapor of the test liquid onto the solid surface is apparently the only process that influences the solid-vapor interfacial tension (gamma(sv)). The molecular interactions taking place at the solid-liquid interface are more diverse and complicated. Parallel alignment of liquid molecules at the solid surface, reorganization of liquid molecules at the solid-liquid interface, change in the configuration of polymer chains due to contact with certain probe liquids, and intermolecular interactions between solid and liquid molecules cause the solid-liquid interfacial (gamma(sl)) tension to be different from that predicted by the equation of state, i.e., gamma(sl) is not a precise function of gamma(lv) and gamma(sv). In other words, the experimental contact angles deviate from the "ideal" contact angle pattern. Specific criteria are proposed to identify probe liquids which eliminate specific molecular interactions. Octamethylcyclotetrasiloxane (OMCTS) and decamethylcyclopentasiloxane (DMCPS) are shown to meet those criteria, and therefore are the most suitable liquids to characterize surface tensions of low energy fluoropolymer films with an accuracy of +/-0.2 mJ/m2.     

The wettability of polytetrafluoroethylene by aqueous solution of cetyltrimethylammonium bromide and Triton X-100 mixtures

Measurements of the advancing contact angle (theta) were carried out for aqueous solution of cetyltrimethylammonium bromide (CTAB) and p-(1,1,3,3-tetramethylbutyl) phenoxypoly(ethylene glycol), Triton X-100 (TX100) mixtures on polytetrafluoroethylene (PTFE). The obtained results indicate that the wettability of PTFE depends on the concentration and composition of the surfactants mixture. There is a minimum of the dependence between contact angle and composition of the mixtures for PTFE for each concentration at a monomer mole fraction of CTAB, alpha, equal 0.2, which points to the synergism in the wettability of PTFE. In contrast to Zisman, there is no linear dependence between costheta and the surface tension of aqueous solution of CTAB and TX100 mixtures for all studied systems, but a linear dependence exists between the adhesional tension and surface tension for PTFE in the whole concentration range, the slope of which is -1, that suggests that the surface excess of the surfactant concentration at the PTFE-solution interface is the same as that at the solution-air interface for a given bulk concentration. It was also found that the work of adhesion of aqueous solution of surfactants to PTFE surface did not depend on the type of surfactant and its concentration. It means that the interactions across PTFE-solution interface were constant for the systems studied, and they were largely Lifshitz-van de Waals type. On the basis of the surface tension of PTFE and the Young equation and thermodynamic analysis of the adhesion work of aqueous solution of surfactant to the polymer surface it was found that in the case of PTFE the changes of the contact angle as a function of the mixture of nonionic and cationic surfactants concentration resulted only from changes of the polar component of solution surface tension.     

Wettability of a polytetrafluoroethylene surface by an aqueous solution of two nonionic surfactant mixtures

Measurements of the advancing contact angle (theta) were carried out for an aqueous solution of p-(1,1,3,3-tetramethylbutyl)phenoxypoly(ethylene glycol)s (Triton X-100 (TX100) and Triton X-165 (TX165) mixtures) on polytetrafluoroethylene (PTFE). The obtained results indicate that the wettability of PTFE depends on the concentration and composition of the surfactant mixture. The minimum of the dependence between the contact angle and composition of the mixtures for PTFE for each concentration at a monomer mole fraction of TX100, alpha = 0.8, points to synergism in the wettability of PTFE. This effect was confirmed by the negative values of interaction parameters calculated on the basis of the contact angle and by the Rosen approach. In contrast to Zisman, there was no linear dependence between cos theta and the surface tension of an aqueous solution of TX100 and TX165 mixtures for all studied systems, but a linear dependence existed between the adhesional tension and surface tension for PTFE over the whole concentration range, the slope of which was -1, indicating that the surface excess of the surfactant concentration at the PTFE-solution interface was the same as that at the solution-air interface for a given bulk concentration. Similar values of monomer mole fractions of the surfactants at water-air and PTFE-water interfaces calculated on the basis of the surface tension and contact angles showed that adsorption at these two interfaces was the same. It was also found that the work of adhesion of an aqueous solution of surfactants to the PTFE surface did not depend on the type of surfactant and its concentration. This means that for the studied systems the interaction across the PTFE-solution interface was constant and was largely of Lifshitz-van der Waals type. On the basis of the surface tension of PTFE, the Young equation, and the thermodynamic analysis of the adhesion work of an aqueous solution of surfactant to the polymer surface, it was found that in the case of PTFE the changes in the contact angle as a function of the mixture concentration of two nonionic surfactants resulted only from changes in the polar component of the solution surface tension.     

亚砜类非离子型表面活性剂在固/液界面上的吸附(III)碳黑/水溶液界面上的吸附

研究了癸基甲基亚砜在水溶液/炭黑界面上的吸附及温度、加盐(Nacl)、加酸(HCl)对吸附的影响.吸附等温线呈完整的双平台形式. 第一平台吸附量～6 μmol·m~(-2); 第二平台吸附量,即极限吸附量, 为42—48 μmol·m~(-2). 随着吸附增加, 炭黑/水溶液接触角下降, 润湿性, 悬浮性改善.应用两阶段吸附模型和吸附等温线通用公式可以对实验结果作定性和定量的解释. 提供了吸附热力学数据. 指示吸附第二阶段是与体相中表面活性剂胶团化作用相似的熵驱动过程。     

The wettability of polytetrafluoroethylene and polymethyl methacrylate by aqueous solution of two cationic surfactants mixture

Advancing contact angle (theta) measurements were carried out for aqueous solutions of cetyltrimethylammonium bromide (CTAB) and cetylpyridinium bromide (CPyB) mixtures on polytetrafluoroethylene (PTFE) and polymethyl methacrylate (PMMA). The obtained results indicate that the wettability of PTFE and PMMA by aqueous solutions of CTAB and CPyB mixtures depends on the composition and concentration of the mixture; however, synergism in the wettability does not exist. In the range of low concentrations of aqueous solution mixtures there is a linear dependence between the contact angle and composition of the mixtures, but at a concentration close to CMC a deviation from linear dependence is observed. In contrast to Zisman, there is no linear dependence between costheta and the surface tension of aqueous solution of CTAB and CPyB mixtures, but a linear dependence exists between the adhesional and surface tension, and these lines have a slope -1 and -0.34 for PTFE and PMMA, respectively, which suggests that adsorption of CTAB and CPyB mixtures at water-air and PTFE-water is the same, and the orientation of the CTAB and CPyB molecules at both interfaces in the saturated monolayer should also be the same. Adsorption of these mixtures at water-air interface is considerably higher than at PMMA-water interface, and CTAB and CPyB molecules should be parallelly oriented to PMMA surface in the saturated monolayer. Extrapolation of the straight lines to the points corresponding to the surface tension of aqueous solution, which completely spreads over the PTFE and PMMA surface, gives a critical surface tension of wetting equal to 23.44 and 33.13 mN/m, respectively. The value of 23.44 mN/m is higher than that of the surface tension of PTFE, but the value of 33.13 is lower than that of Lifshitz-van der Waals components of PMMA surface tension. On the basis of the critical surface tension, the surface tension of PTFE and PMMA, the Young equation, and thermodynamic analysis of the adhesion work of aqueous solution of surfactant to polymer surface, it was found that for PTFE and PMMA the changes of the contact angle of aqueous solution of two cationic surfactants mixtures on their surfaces as a function of the solution concentration resulted only from the decrease of the polar component of the solution surface tension.     

Importance of surface tension for physical paint properties

Surface tension is a parameter of decisive importance for characterizing painted and unpainted surfaces related to wetting and adhesion phenomena. This article presents measurements of the surface tension of solids by means of an automatic contact angle measurement device. The evaluation of the surface tension is based on a separation into polar and disperse components. In addition, this paper briefly touches on other, more far-reaching approaches (acid/base) and discusses a method for the determination of dynamic surface tension of liquids.