摘要
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ΔGad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.
The relationship of surface property and hydrophobic branched-chain structure was studied using four branched-alkylbenzenesulfonates with additional alkyl substituents synthesized by our laboratory. From the surface tension measurements in pure water and 0.171 mol (.) L-1 NaCl solutions, the following parameters were calculated: critical micelle concentration (cmc), the surface tension at the cmc (gamma(cmc)), surface excess at the cmc, (Gamma(max)), area per molecule at the cmc (A(min)), p c(20), and standard free energy of adsorption (DeltaG(ad)(circle minus)). Lengthening the branched alkyl chain at the meta-position of sulfonic group, Gamma(max) decreased while gamma(cmc) decreased; at the same time, cmc decreased, p c(20) increased, and DeltaG(ad)(circle minus) became more negative. These results indicated that the hard-disk areas of sodium branched-alkylbenzenesulfonate molecules (a(s)) affected adsorption and surface tension.
出处
《物理化学学报》
SCIE
CAS
CSCD
北大核心
2004年第12期1451-1454,共4页
Acta Physico-Chimica Sinica
基金
国家重点基础研究发展规划项目(G19990225)资助~~
关键词
多支链烷基苯磺酸钠
分子独占面积
临界胶束浓度
饱和吸附量
表面张力
sodium branched-alkylbenzenesulfonates
hard-disk areas of surfactant molecules
cmc
saturation adsorption amount
surface tension
