乳液体系中影响分散相粒子大小及分布的因素——cmcO及cmcW的协同作用

用马尔文MastersizerMicroplus型激光粒度仪对液体石蜡及环氧树脂E-20与甲苯等有机溶剂以不同比例所形成的体系经乳化后的粒子大小及分布进行研究,结果表明,随着油溶性表面活性剂在油相中溶解性的改善,分散相的粒子大小及分布也明显得到改善.cmcO及cmcW的协同作用对获得理想的分散相粒子大小及分布起到了至关重要的作用     

多支链烷基苯磺酸钠水溶液的表面性质

用自制的四种高纯度多支链烷基苯磺酸钠,研究了支链结构对其表面性质的影响.结果表明,随支链烷基碳数增加,临界胶束浓度降低,标准吸附自由能DGadӨ更负;但是,饱和吸附量Γmax却随支链烷基碳数增加而减小,且临界胶束浓度时的表面张力γcmc随吸附量减小而降低,表现出与一般表面活性剂不同的变化趋势.从多支链烷基苯磺酸钠的分子结构特点,解释了随支链烷基碳数增加Γmax和γcmc的变化规律,探讨了分子的独占面积(as)对Γmax及γcmc的影响.     

Mixtures of antidepressant amphiphilic drug imipramine hydrochloride and anionic surfactant: Micellar and thermodynamic investigation

Aggregation as well as thermodynamic behavior of amphiphilic imipramine hydrochloride (IMH) drug (antidepressant) and anionic surfactant (sodium dodecyl sulfate [NaDS] as well as sodium dodecylbenzenesulfonate [NaDBS]) mixtures as a function of solution composition in aqueous solutions have been evaluated by conductometry method at different temperatures. Surfactant (NaDS and NaDBS) employed in the current study is anionic in nature. Various theoretical models such as Clint, Rubingh, Motomura, and Rodenas were employed to gain information regarding the type of interaction between the components in the solution mixtures. The value of micellar mole fraction evaluated by different utilized models is found to be more for IMH‐NaDBS mixtures in comparison with IMH‐NaDS mixtures, signifying that participation of NaDBS is more in mixed micelles as compared with NaDS. Owing to the different charge of employed drug and surfactant, which sources high synergistic results in the mixed system comparative to the possessions of their pure compounds, means here anionic surfactants were elected in favor of the quantitation of cationic drug. The value of interaction parameters (β) was also evaluated by employing the Rubingh's model. The values of Gibbs free energy (?G⁰_m) for all systems attained to be negative in all studied systems showing that the systems are spontaneous in nature.     

Synthesis and Surface Activity of Anionic Gemini Surfactants with Alkyl Spacers

A series of anionic Gemini surfactants called alkanediyl-α,ω-bis(m-octylphenoxy sulfonate) with different length of (CH₂)_x spacer, C₈C_xC₈ (x = 2, 4, 6, 8), have been synthesized from 4-n-octylphenol and their basic physicochemical properties are investigated. The results indicate that they are different from cationic Gemini surfactants called alkanediyl-α,ω-bis(dimethyldodecylammonium bromide), 12-(CH₂)_s-12, in the literature. It is found that as the carbon atom number of the spacer increases, the cmc (critical micelle concentration) decreases gradually, and the surface area per molecule (A_min) decreases initially and then increases. The breakpoints appear at number 4 of carbon atom in the spacer. Though the length of the spacer is different for the Gemini surfactants from C₈C₂C₈ to C₈C₆C₈, there is no obvious change on the micropolarity.     

A theoretical model for the critical micelle concentration of bile salts

Critical micelle concentration (CMC) is a fundamental parameter in the evaluation of the biological activity of natural and synthetic bile salts. The CMC is logarithmically related to the free energy of solute micellization in aqueous solution. Hydrophobic and hydrogen bonding interaction energies were identified as the primary contributors to this free energy and the logarithm of the CMC was modeled as a linear function of relevant chemical group contributions to the solvent accessible molecular surface area of the solute. The structures (three-dimensional atomic coordinates) of 23 mono-, di-, and tri-hydroxyl bile acids were generated and optimized by energy minimization. The accessible surface area for each structure was computed and partitioned according to calculated charge distribution and polar group orientation. Experimental CMC values were fitted to these computed quantities by least squares multiple linear regression. Two regression equations, based on slightly different surface area partition schemes, were derived and compared. Their significance in explaining the aggregation process and in predicting the CMC of new bile salts is discussed.     

吸收光谱线型分析用于十六烷基溴化铵临界胶束浓度的测量

十六烷基溴化铵;临界胶束浓度;分光光度法;高斯多峰拟合;半高宽     

水介质中药物-AOT混合物的温度依赖的混合胶束化行为(英文)

The mixed micellization behavior of an amphiphilic antidepressant drug amitriptyline hydrochloride(AMT)in the presence of the conventional anionic surfactant sodium bis(2-ethylhexyl)sulfosuccinate(AOT)was studied at five different temperatures and compositions by the conductometric technique.The critical micelle concentration(cmc)and critical micelle concentration at the ideal state(cmcid)values show mixed micelle formation between the components(i.e.,drug and AOT).The micellar mole fractions of the AOT(X1)values calculated using the Rubingh,Motomura,and Rodenas models show a higher contribution of AOT in the mixed micelles.The interaction parameter(β)is negative at all temperatures and the compositions show attractive interactions between the components.The activity coefficients(f1and f2)calculated using the different proposed models are always less than unity indicating non-ideality in the systems.TheΔGmΘ values were found to be negative for all the binary mixed systems.However,ΔHmΘ values for the pure drug as well as the drug-AOT mixed systems are negative at lower temperatures(293.15-303.15 K)and positive at higher temperatures(308.15 K and above).TheΔSmΘ values are positive at all temperatures but their magnitude was higher at T=308.15 K and above.The excess free energy of mixing(ΔGex)determined using the different proposed models also explains the stability of the mixed micelles compared to the pure drug(AMT)and surfactant micelles.     

头孢唑酮对CTAB胶束结构特性的影响

应用电导法和荧光法测定了头孢唑酮对阳离子表面活性剂十六烷基三甲基溴化铵（CTAB）胶束第一cmc1、第二cmc2、胶束聚集数及体系粘度的影响,测定了头孢唑酮在CTAB胶束中的分配系数.结果表明,头孢唑酮的加入使得CTAB胶束的第一cmc和第二cmc均上升,胶束的聚集数和体系的粘度降低.上述结果与头孢唑酮和CTAB分子的相互作用及其在CTAB胶束相和水连续相的分配有关.     

可聚硼酸酯表面活性剂的表面化学性质及与LAS相互作用

用表面张力法研究了可聚合硼酸酯表面活性剂(BES)水溶液不同温度下(288-313 K)的表面活性和热力学函数变化；考察了BES与十二烷基苯磺酸钠(LAS)在0.5 mol·L-1 NaCl溶液中的相互作用. 结果表明, 298 K时, BES临界胶束浓度cmc达到0.066 mmol·L-1, γcmc为29.2 mN·m-1；在所考察的温度范围内BES胶束形成自由能(ΔG0m)在-22.4 - -25.8 kJ·mol-1之间, 胶束形成是熵驱动过程. BES/LAS混合体系为具有较大负偏差的非理想体系, BES/LAS分子间平均相互作用参数βm=-3.48；当溶液体相中BES摩尔分数αBES＝0.5时, 混合胶束中BES摩尔分数X1m为0.46, |βm|达到最大, 而且此时混合溶液cmc为0.017 mmol·L-1, 达到最低, γcmc为27.8 mN·m-1.     

青霉素钾对CTAB胶束性质的影响

研究了青霉素钾对十六烷基三甲基溴化铵（CTAB）的cmc、CTAB胶束聚集数和扩散系数的影响.研究结果表明，青霉素钾(Pen K)的加入使得CTAB胶束的第一cmc、第二cmc上升；CTAB球形胶束的聚集数下降,扩散系数增加；CTAB棒状胶束的聚集数增加,扩散系数降低.