Kang HC, Lee BM, Yoon J, Yoon M
Applied and Engineering Chemistry Division, Korea Research Institute of Chemical Technology, Taejon, 305-600, Korea
J Colloid Interface Sci. 2000 Nov 15;231(2):255-264. doi: 10.1006/jcis.2000.7158.
Several water-soluble cationic surfactants, 4-alkylazobenzene-4'-(oxy-2-hydroxypropyl)trimethylammonium methylsulfate (AZMS) (AZMS-0, AZMS-1, AZMS-2, AZMS-4, and AZMS-8), containing alkylglycidylether and azoarene have been synthesized with high yields of 63-78% and their surface-active properties have been investigated upon irradiation with UV/vis light. All of the trans-AZMS surfactants are isomerized to cis-trans mixtures containing 92.5% cis isomer by UV light irradiation at 350 nm. The cis isomers in the mixtures are reverted to trans isomers by visible light irradiation (lambda>445 nm). Such photoisomerization induces changes in the surface activity of each surfactant. The critical micelle concentration (cmc) of the trans form of AZMS-8 surfactant is about 1.28x10(-4) mol/l. At the photostationary state, 92.5% of the trans form is changed to the cis form which exhibits a slightly higher cmc (3.41x10(-4) mol/l). The new cmc of AZMS surfactants upon photoisomerization is similar to that of the ideal mixed micellar system. In particular, the ratio of cmc(cis) to cmc(trans) of AZMS derivatives is about 1.87-2.85 which increases proportionally with the chain length of alkyl group. The minimum average area per molecule (A(min)(a/w)) for the trans and cis isomers of AZMS-8 is 0.60 and 0.74 nm(2), respectively. The difference in the A(min)(a/w) may originate from the structural differences in the two isomers. These values are quite different as compared to those of the conventional azobenzene surfactants. Copyright 2000 Academic Press.
几种含有烷基缩水甘油醚和偶氮芳烃的水溶性阳离子表面活性剂，4-烷基偶氮苯-4'-(氧-2-羟丙基)三甲基硫酸甲酯铵(AZMS)(AZMS-0、AZMS-1、AZMS-2、AZMS-4和AZMS-8)已被高收率(63 - 78%)合成，并研究了它们在紫外/可见光照射下的表面活性。所有反式AZMS表面活性剂在350 nm紫外光照射下异构化为含有92.5%顺式异构体的顺反混合物。混合物中的顺式异构体通过可见光照射(λ>445 nm)恢复为反式异构体。这种光异构化引起了每种表面活性剂表面活性的变化。AZMS-8表面活性剂反式形式的临界胶束浓度(cmc)约为1.28×10(-4)mol/L。在光稳定状态下，92.5%的反式形式转变为顺式形式，其cmc略高(3.41×10(-4)mol/L)。光异构化后AZMS表面活性剂的新cmc与理想混合胶束体系的cmc相似。特别是，AZMS衍生物的cmc(顺式)/cmc(反式)比值约为1.87 - 2.85，随烷基链长度成比例增加。AZMS-8反式和顺式异构体的每分子最小平均面积(A(min)(a/w))分别为0.60和0.74 nm(2)。A(min)(a/w)的差异可能源于两种异构体的结构差异。与传统偶氮苯表面活性剂相比，这些值有很大不同。版权所有2000年学术出版社。
