Daful Asfaw Gezae, Mackie Allan D
School of Chemical and Bio Engineering, Addis Ababa Institute of Technology, Addis Ababa University, P.O. Box 385, Addis Ababa, Ethiopia.
Departament d'Enginyeria Química, ETSEQ, Universitat Rovira i Virgili, Av. dels Països Catalans 26, 43007 Tarragona, Spain.
J Chem Phys. 2014 Mar 14;140(10):104905. doi: 10.1063/1.4867894.
The concentration induced shape transitions of linear model surfactants, H(x)T(y), on a lattice have been studied using Monte Carlo simulation. It has been found that a sphere to cylinder shape transition is generally found on shortening the hydrophilic part of the surfactant and anticipates an eventual phase transition. Asymmetric surfactants with longer heads than tails (x > y) prefer to form only spherical micelles independent of total surfactant concentration while asymmetric surfactants with longer tails than heads (x < y) form spherical micelles at lower concentration and undergo a shape transition to cylindrical micelles on increasing the total concentration. Finally, in the case of symmetric surfactants with x = y, only the shortest surfactants H1T1 and H2T2 undergo a sphere to cylinder shape transition on increasing surfactant concentration. Longer symmetric surfactants are always found to prefer to form spherical micelles.
利用蒙特卡罗模拟研究了线性模型表面活性剂H(x)T(y)在晶格上浓度诱导的形状转变。研究发现，在缩短表面活性剂的亲水部分时，通常会出现从球形到圆柱形的形状转变，并预示着最终的相变。头比尾长的不对称表面活性剂（x > y），无论总表面活性剂浓度如何，都倾向于仅形成球形胶束；而尾比头长的不对称表面活性剂（x < y）在较低浓度下形成球形胶束，并在增加总浓度时经历形状转变为圆柱形胶束。最后，对于x = y的对称表面活性剂，只有最短的表面活性剂H1T1和H2T2在增加表面活性剂浓度时会发生从球形到圆柱形的形状转变。发现较长的对称表面活性剂总是倾向于形成球形胶束。
