碳氟表面活性剂与碳氢表面活性剂混合水溶液的表面吸附和胶团形成 Ⅰ.全氟辛酸钠-溴化辛基三甲铵体系

测定了一系列不同比例的全氟辛酸钠(7CFNa)-溴化辛基三甲铵(C_8NBr)混合水溶液(μ=O.1mol·kg~(-1)的表面张力.自表面张力-浓度关系求出混合体系的cmc和溶液表面吸附;研究了混合溶液在油面上的铺展性能.结果表明:(1)混合体系的表面活性远高于单一的C_8NBr或7CFNa,两个组分在表面活性上相互促进;(2)混合溶液的总饱和吸附量(Γ_T)随7CFNa/C_8NBr摩尔比的减小而增加:自100/1时的4.7×10~(-10)mol·cm~(-2)增至1/300时的7.3×10~(-10)mol·cm~(-2)(相应的分子面积为22.7A~2).这主要是由于碳氟链的疏水性远较碳氢链为大(虽然后者碳原子数较多);(3)7CFNa-C_8NBr溶液的表面层有独特的结构.不同于一般正、负碳氢表面活性剂混合溶液.基于表面层吸附分子面积的计算结果,并考虑到碳氟链与碳氢链间的互憎作用及正、负电荷的相互吸引作用,提出表面吸附层可能为双分子层结构的假设;(4)混合溶液的极限表面张力很低(～15mNm~(-1)),溶液-正庚烷界面张力亦然(～O.4mNm~(-1));即使溶液浓度及7CFNa与C_8NBr之比相当小时亦如此.因此,这种稀水溶液能在正庚烷、汽油等油面上铺展成(水)膜,故此种碳氟、碳氢表面活性剂混合物可用作“轻水”灭火剂配方中极有效的成分.     

表面活性剂在低能固体表面上的吸附——Ⅱ. 粘附张力法研究碳氟与碳氢表面活性剂的吸附

研究了直接测定粘附张力、推算表面活性剂在低能固体表面上吸附的方法。与文献结果比较, 说明此法可行, 且较γ-θ法~[4]方便、准确、重复性好。研究了C_(12)H_(25)-SO_4Na、C_(16)H_(33)N(CH_3)_3Br、C_7F_(15)COONa水溶液与聚四氟乙烯、石蜡、甲基化玻璃、聚甲基丙烯酸甲醋界面上的粘附张力及吸附, 结果表明: (1)各种表面活性剂在四种固体上的饱和吸附量顺序皆为~ΓPTFE>~ΓAE>~ΓMG>~ΓPMMA与各固体对水粘附张力增加的顺序相同; (2)改善固体亲水性的能力, 对于碳氟固体, 碳氟表面活性剂优于碳氢表面活性剂, 对于碳氢固体则相反。     

碳氟表面活性剂与碳氢表面活性剂混合水溶液的表面吸附和胶团形成——Ⅱ.全氟辛酸钠-十烷基硫酸钠体系

测定了不同摩尔比的全氟辛酸钠(7CFNa)-十烷基硫酸钠(C_(10)SNa)混合水溶液(加NaCl,恒定离子强度μ=0.1m)的表面张力和界面张力(正庚烷-水溶液界面张力)。由表(界)面张力-浓度关系求出混合体系的表(界)面吸附和临界胶团浓度(cmc)。结果表明:(1)7CFNa和C_(10)SNa在μ=0.1m的溶液中,cmc相近,两者表面活性相近;但7CFNa降低水表面张力的能力较强,在cmc时的表面张力可低达～23mNm~(-1)。因此,在混合溶液的表面上,7CFNa的表面活性较高,优先吸附于表面。对于各种摩尔比的混合溶液,7CF~-在表面层中的比例皆大于在溶液内部的比例。(2)正庚烷-水溶液界面上的吸附与表面吸附截然不同。7CF~-在界面吸附层中的比例低于溶液内部,表明其吸附能力比C_(10)S~-为弱。这是由于界面一边的正庚烷与C_(10)SNa碳氢链之间的作用大于与7CFNa碳氟链之间的作用。亦即碳氟链与碳氢链“互憎”作用在界面上的表现。(3)在不同摩尔比的混合溶液中,各组分的cmc接近一恒值,进一步说明混合溶液中存在碳氟链与碳氢链间的互憎作用,以致两种表面活性剂在混合溶液中(有过量无机盐时)基本上各自形成胶团。     

表面活性剂在低能固体表面上的吸附Ⅰ. γ-θ法研究辛基硫酸钠、溴化辛基三甲胺及其等比混合物在石蜡/水溶液界面上的吸附

(1) 用γ-θ法研究C_8H_(17)SO_44Na、C_8H_(17)N(CH_3)_3Br及其1:1混合物在石蜡/水溶液界面上的吸附, 得到Langmuir型吸附等温线。 (2) 首次计算两表面活性剂在固/液界面吸附层中的分子相互作用参数, 并与它们在气/液、液/液界面吸附层中的数值相比较。 (3) 结果表明γ-θ法不仅简单、方便、样品用量少, 而且有获得信息多的特点, 用几毫升样品可得到有关体系表面性质的十多种数据。     

辛基甲基亚砜与离子型表面活性剂在水溶液中的相互作用

本文用测定表面张力的方法研究了非离子表面活性剂辛基甲基亚砜(OMS)分别与离子型表面活性剂C_(10)H_(21)SO_4N_a(SDeS)、C_7F_(15)COONa(SPFO), C_(10)H_(21)N(CH_3)_3B_r(DeTAB)等在水溶液中的相互作用。发现上述混合体系的胶团形成及表面吸附都有不同程度的增效作用; 表面活性分子在吸附层中的相互作用参数β~s以及在胶团中的相互作用参数β~m均为负值并有一定变化规律; OMS与DeTAB的相互作用较OMS与SDeS或SPFO的相互作用弱得多; 此现象自OMS分子在水溶液中的质子化作用得到解释。     

碳氟醇与阴离子表面活性剂的相互作用

测定了不同比例的C_(10)_H_(21)SO_4Na-C_3F_7CH_2OH、C_7F_(15)COONa-C_3H_7CH_2OH混合水溶液的表面张力,加入C_3F_7CH_2OH可增加阴离子表面活性剂的表面活性;在表面层中,C_3F_7CH_2OH与C_(10)H_(21)SO_4Na间分子相互作用比C_3F_7CH_2OH-C_7F_(15)COONa体系弱;这是由于CF链与CH链间“互疏”作用的结果;随着C_3F_7CH_2OH浓度增加,对C_(10)H_(21)SO_4Na胶团反离子结合度也随之增加。     

不等链长的碳氟、碳氢正负离子表面活性剂混合体系的表面活性

研究了全氟辛酸钠与溴化十四烷基三甲铵混合水溶液的表面活性. 测定了不同比例混合物水溶液的表面张力-浓度曲线, 得出临界胶团浓度(cmc)及监 界胶团浓度时的溶液表面张力(γcmc)值. 应用Gibbs吸附公式及吸附层中两表面活性剂分子相互作用参数法求出表面总吸附量、吸附层组成及两表面活性剂分别吸附量等. 指示此吸附层具有多分子层性质. 这可能是碳氢、碳氟正负离子混合体系的特点.     

含羧基的三核钼原子簇

本文总结了作者研究的一组合有羧基的三核钼原子簇的结果。这些簇合物分为两类。第一类有: (C_2H_5)_4N[Mo_3(μ_3-O)(μ-O_2CH)_3(μ-Cl)_3Cl_3] (Ⅰ) (CH_3)_4N[Mo_3(μ_3-O)(μ-O_2CH)_3(μ-Cl)_3Cl_3] (Ⅱ) (CH_3)_4N[Mo_3(μ_3-O)(μ-O_2CH)_3(μ-Br)_3Cl_3] (Ⅲ) (C_5H_7S_2)[Mo_3(μ_3-O)(μ-O_2CCH_3)_3(μ-Cl)_3Cl_3] (Ⅳ) (C_5H_7S_2)[Mo_3(μ_3-O)(μ-O_2CCH_3)_3(μ-Br)_3Cl_3] (Ⅴ) (C_2H_5)_4N[Mo_3(μ_3-O)(μ-O_3CCH_3)(μ-Cl)_3X_3] (Ⅵ) (X为Cl和Br统计分布的簇合物) (C_2H_5)_4N[Mo_3(μ_3-O)(μ-O_2CCH_2CH_3)_3(μ-Cl)_3Cl_3] (Ⅶ) (C_2H_5)_4N[Mo_3(μ-O)(μ-O_2CCH_2CH_2CH_3)_3(μ-Cl)_3Cl_3] (Ⅷ) (Ⅰ)-(Ⅷ)的簇阴离子具有下述通式: [Mo_3(μ_3-O)(μ-O_2CR)_3(μ-X)_3X_3~′]~-; R=H,CH_3,CH_3CH_3,CH_2CH_2CH_2:X和X′=Cl或Br。 属于第二类型的目前只有一个,即: [(C_2H_5)_4N]_2[Mo_3(μ_3-O)(μ-O_2CCH_3)_2(μ-Cl)_3Cl_5) (Ⅸ) 本文将扼要介绍这些簇合物的合成方法,晶体和分子结构的主要特征,并对成簇规律、结构变化规律以及μ_3-O的红外光谱的指认,给予简单的讨论。     

芳香叔胺引发丙烯腈光聚合的引发机理

芳香叔胺引发丙烯腈(AN)光聚合是通过形成激基复合物(exciPlex)进行的。紫外光谱和荧光光谱表明,芳香叔胺在基态可以和AN形成电荷转移复合物(CTC),而在激发态可和AN形成exciplc(称定域激发)。CTC经光照亦可激发(称CTC激发)。 定域激发引起光聚合速率为CH_3C_6H_4N(CH_3)_2>C_6H_5N(CH_3)_2>HOCH_2·C_6H_4N(CH_3)_2>CH_3C_6H_4N(CH_2CH_2OH)_2,与芳胺荧光被AN淬灭的Stern-Vo-lmer常数顺序一致。CTC激发引起的光聚合顺序为:CH_3C_6H_4N(CH_3)_2>CH_3C_6H_4N(CH_2CH_2OH)_2>HOCH_2C_6H_4N(CH_3)_2>C_6H_5N(CH_3)_2,与芳胺上取代基推电子能力一致。端基分析表明聚合物有芳胺端基。     

碳氟-碳氢表面活性剂混合水溶液在油面上铺展

本文研究RfCONH(CH2)3N(C2H5)2CH3I/CnH2n 1,COONa及RfCOONa/CmH2m 1N(CH3)3Br(Rf=F[CF(CF3)CF2O]2CF(CF3);n=7,8.11,13;m=8,10,12)两类正，负离子碳氟－碳氢表面活性剂混合水溶液在油面上的铺展及对油面的密封性能。研究表明在碳氟表面活性剂中加入异电性碳氢表面活性剂可大大降低碳氟表面活性剂水溶液的铺展浓度，也可使一些因素表面张力较高而不能铺展的碳氟表面活性剂水溶液在油面上铺展。在碳氟表面活性剂中加入异电性碳氢表面活性剂可提高水膜对油面的密封性。若在混合表面活性剂中加入黄原胶，水膜的密封性能更好。     

碳氟表面活性剂与碳氢表面活性剂混合水溶液的表面吸附和胶团形成 I: 全氟辛酸钠-溴化辛基三甲铵体系

The surface adsorption and micelle formation of the mixed aqueous solutions of sodium perfluorooctanoate (7CFNa) and n-octyltrimethylamonium bromide (C8NBr) have been investigated by studying the surface tension-concentration relations of the solutions. It has been found that (1) The surface activity of the mixed system is much higher than that of 7CFNa and C8NBr. C8NBr is a very effective synergist for 7CFNa in surface activity, and vice versa. (2) By applying Gibbs adsorption equation, the total amount of adsorption (\I\t), the individual adsorption amount of the single surfactants (\I\7CF-, \I\C8N+) and the average molecular areas of them have been calculated. The adsorption value (saturated, \I\T) increases by 54% as the molal ratio of 7CFNa-C8NBr varies from 100:1 to 1:300. (3) From the adsorption data, it appears that the structure of surface layer of the 7CFNa-C8NBr solutions is peculiar and quite different from that of the cationic-anionic hydrocarbon surfactants. Firstly, the molal ratio of the two components in the surface layer of the 1:1 mixed solution is not 1:1 (7CFNa is adsorbed perferentially). Secondly, the molecular area at the maximum adsorption is very small (22.7A2). This could be attributed to the balancing of the electrical attraction between positive and negative ions and the mutual phobicity between the fluorocarbon and hydrocarbon chains. It has been concluded that the saturated adsorption film would possibly have a double-layer structure: the upper layer consists of the oriented 7CF- with the fluorocarbon chain toward the gaseous phase and the lower layer consists of randomly oriented C8N+ with the positive ionic head attached to the negative ionic head of 7CF- -- thus the 7CF- adsorption layer would behave as a platform for the adsorption of C8N+. (4) The limiting surface tension of the mixed solutions is very low (-15mNm-1) even if the molal ratio of 7CFNa-C8NBr is small, and so is the oil-water interfacial tension. Therefore it is capable of spreading the dilute aqu     

The surface adsorption and micelle formation of the mixed aqueous solutions of fluorocarbon and hydrocarbon surfactants: II. Sodium perfluorooctanoate-sodium decylsulfate system

The adsorption and micellar behavior of the mixed solutions of sodium perfluorooctanoate (7CFNa) and sodium decylsulfate (C₁₀SNa) have been studied at constant ion strength of 0.1m. The adsorption was calculated from the surface (and interfacial) tension-concentration curves by applying Gibbs equation. It was found that the cmc's of 7CFNa and C₁₀SNa are of nearly the same value (1.66 × 10⁻²m and 1.45 × 10⁻²m, respectively), but γ_cmc of 7CFNa solution is ∼23 mNm⁻¹, which is much lower than that of C₁₀SNa solution. This implies that 7CFNa would have a much higher surface activity than C₁₀SNa and be adsorbed preferentially; for instance, 7CFNa has a surface mole fraction of about 0.8 in the saturated adsorption layer of the 1:1 mixed solution. The mole fractions of 7CFNa at the surface are always greater than those in the bulk solutions. The adsorption at the n- heptane-aqueous solution interface is quite different from that at the air-solution surface. Here C₁₀SNa is preferentially adsorbed owing to “Mutual phobicity” between the HC-chain of n-heptane and the FC-chain of 7CFNa at the interface. All the cmc's obtained from the γ-log m relations of 7CFNa (or C₁₀SNa) in the mixed solutions have nearly the same value and the cmc-x curves show a positive deviation from the ideal case. This further indicates that in the mixed solutions of fluorocarbon and hydrocarbon surfactants no completely miscible micelle but essentially the individual micelle of each surfactant exist due to the “Mutual phobicity” between FC- and HC-chain in the micellization process.     

The influence of mixed cationic–anionic surfactants on the three-phase contact parameters in silica–solution systems

The formation of thin wetting films on silica surface from aqueous solution of (a) tetradecyltrimetilammonium bromide (C₁₄TAB) and (b) surfactant mixture of the cationic C₁₄TAB with the anionic sodium alkyl- (straight chain C₁₂–, C₁₄– and C₁₆–) sulfonates, was studied using the microscopic thin wetting film method developed by Platikanov. Film lifetimes, three-phase contact (TPC) expansion rates, receding contact angles and surface tension were measured. It was found that the mixed surfactants caused lower contact angles, lower rates of the thin aqueous film rupture and longer film lifetimes, as compared to the pure C₁₄TAB. This behavior was explained by the strong initial adsorption of interfacial complexes from the mixed surfactant system at the air/solution interface, followed by adsorption at the silica interface. The formation of the interfacial complexes at the air/solution interface was proved by means of the surface tension data. It was also shown, that the chain length compatibility between the anionic and cationic surfactants controls the strength of the interfacial complex and causes synergistic lowering in the surface tension. The film rupture mechanism was explained by the heterocoagulation mechanism between the positively charged air/solution interface and the solution/silica interface, which remained negatively charged.     

Dynamical and rheological properties of fluorinated surfactant films adsorbed at the pressurized CO2-H2O interface

The dynamics of adsorption, interfacial tension, and rheological properties of two phosphocholine-derived partially fluorinated surfactants FnHmPC, designed to compensate for the weak CO(2)-surfactant tail interactions, were determined at the pressurized CO(2)-H(2)O interface. The two surfactants differ only by the length of the hydrocarbon spacer (5 CH(2) in F8H5PC and 11 CH(2) in F8H11PC) located between the terminal perfluoroalkyl chain and the polar head. The length of this spacer was found to have a critical impact on the adsorption kinetics and elasticity of the interfacial surfactant film. F8H5PC is soluble in both water and CO(2) phases and presents several distinct successive interfacial behaviors when bulk water concentration (C(W)) increases and displays a nonclassical isotherm shape. The isotherms of F8H5PC are similar for the three CO(2) pressures investigated and comprise four regimes. In the first regime, at low C(W), the interfacial tension is controlled by the organization that occurs between H(2)O and CO(2). The second regime corresponds to the adsorption of the surfactant as a monolayer until the CO(2) phase is saturated with F8H5PC, resulting in a first inflection point. In this regime, F8H5PC molecules reach maximal compaction and display the highest apparent interfacial elasticity. In the third regime, a second inflection is observed that corresponds to the critical micelle concentration of the surfactant in water. At the highest concentrations (fourth regime), the interfacial films are purely viscous and highly flexible, suggesting the capacity for this surfactant to produce water-in-CO(2) microemulsion. In this regime, surfactant adsorption is very fast and equilibrium is reached in less than 100 s. The behavior of F8H11PC is drastically different: it forms micelles only in the water phase, resulting in a classical Gibbs interface. This surfactant decreases the interfacial tension down to 1 mN/m and forms a strongly elastic interface. As this surfactant forms a very cohesive interface, it should be suitable for formulating stable water-in-CO(2) emulsions. The finding that the length of the hydrocarbon spacer in partially fluorinated surfactants can drastically influence film properties at the CO(2)-H(2)O interface should help control the formation of microemulsions versus emulsions and help elaborate a rationale for the design of surfactants specifically adapted to pressurized CO(2).     

Adsorption of protein-surfactant complexes at the water/oil interface

Interfacial tension measurements have been performed at the water/hexane interface on mixtures of the bovine milk protein β-lactoglobulin and positively charged cationic surfactants (alkytrimethylammonium bromides). The addition of surfactants with different chain lengths leads to the formation of protein-surfactant complexes with different adsorption properties as compared to those of the single protein. In this study, the formation of complexes has been observed clearly for protein-long chain surfactant (TTAB and CTAB) mixtures, which has shown in addition to specific electrostatic interactions the relevance of hydrophobic interactions between surfactant molecules and the protein. The modeling of interfacial tension data by using a mixed adsorption model provides a quantitative understanding of the mixture behavior. Indeed, the value of the adsorption constant of the protein obtained in the presence of surfactants has strongly varied as compared to the single protein. Actually, this parameter which represents the affinity of the molecule for the interface is representative of the hydrophobic character of the compound and so of its surface activity. Even if a more hydrophobic and more surface active protein-surfactant complex has been formed, the replacement of this complex from the interface by surfactants close to their cmc was observed.     

Mutual influence of cetyltrimethylammonium bromide and Triton X-100 on their adsorption at the water–air interface

On the basis of surface tension values of the aqueous solution of cetyltrimethylammonium bromide (CTAB) and Triton X-100 (TX-100) mixtures measured at 293 K as a function of CTAB or TX-100 concentration at constant TX-100 or CTAB concentration, respectively, the real surface area occupied by these surfactants at the water–air interface was established which is inaccessible in the literature. It appeared that at the concentration of the CTAB and TX-100 mixture in the bulk phase corresponding to the unsaturated monolayer at the water air-interface this area is the same as in the monolayer formed by the single surfactant at the same concentration as in the mixture. In the saturated mixed monolayer at this interface the area occupied by both surfactants is lower than that in the single surfactant monolayer corresponding to the same concentration in the aqueous solution. However, the decrease of the CTAB adsorption is lower than that of TX-100 and the total area occupied by the mixture of surfactants is also lower than that of the single one. The area of particular surfactants in the mixed saturated monolayer changes as a function of TX-100 and CTAB mixture concentration and at the concentrations close to CMC or higher the area occupied by both surfactants is the same. The changes of the composition of the mixed surface monolayer are connected with the synergetic effect in the reduction of the water surface tension by the adsorption of CTAB and TX-100 at the water–air interface. This effect was confirmed by the values of the standard Gibbs free energy of adsorption of both individual surfactants and their mixtures with different compositions in the bulk phase determined by using the Langmuir equation if RT instead of nRT was applied in this equation.     

Molecular behavior and synergistic effects between sodium dodecylbenzene sulfonate and Triton X-100 at oil/water interface

Significant synergistic effects between sodium dodecylbenzene sulfonate (SDBS) and nonionic nonylphenol polyethylene oxyether, Triton X-100 (TX-100), at the oil/water interface have been investigated by experimental methods and computer simulation. The influences of surfactant concentration, salinity, and the ratio of the two surfactants on the interfacial tension were investigated by conventional interfacial tension methods. A dissipative particle dynamics (DPD) method was used to simulate the adsorption properties of SDBS and TX-100 at the oil/water interface. The experiment and simulation results indicate that ultralow (lower than 10(-3) mN m(-1)) interfacial tension can be obtained at high salinity and very low surfactant concentration. Different distributions of surfactants in the interface and the bulk solution corresponding to the change of salinity have been demonstrated by simulation. Also by computer simulation, we have observed that either SDBS or TX-100 is not distributed uniformly over the interface. Rather, the interfacial layer contains large cavities between SDBS clusters filled with TX-100 clusters. This inhomogeneous distribution helps to enhancing our understanding of the synergistic interaction of the different surfactants. The simulation conclusions are consistent with the experimental results.     

全氟壬烯氧基苯磺酸钠/辛基酚聚氧乙烯醚-10复配体系的铺展性能

分析全氟壬烯氧基苯磺酸钠(OBS)与辛基酚聚氧乙烯醚-10(OP-10)复配比例对溶液的表面张力、油/水界面张力及铺展性能的影响,寻求最佳复配比例和最佳铺展浓度.研究结果表明,OBS/OP-10混合水溶液与OBS单一组分水溶液相比,表面张力略有增加,界面张力显著降低,因此混合水溶液的铺展性能显著改善,原来在环己烷上不铺展,复配后变得铺展.尤其以质量比为1∶3,浓度为3.12 mmol/L体系水溶液的铺展性能最好,可以在环己烷上快速铺展,而且显著降低了OBS的用量,约降低了67％ OBS用量,提高了经济效益.同时对OBS/OP-10不同复配比例的水溶液最佳铺展浓度进行了研究,发现由表面张力确定的临界胶束浓度、界面张力确定的临界胶束浓度并非最佳铺展浓度,三者之间有一定偏差,其中,最佳铺展浓度介于表面临界胶束浓度、界面临界胶束浓度之间,差额取决于氟碳表面活性剂和碳氢表面活性剂的性质及配比.