阳离子和两性表面活性剂对石英表面润湿性的影响

Effects of Cationic and Zwitterionic Surfactants on Wetting of Quartz Surfaces

利用座滴法研究了阳离子表面活性剂十六烷基醚羟丙基季铵盐(C16PC)和两性离子表面活性剂十六烷基醚羟丙基羧酸甜菜碱(C16PB)溶液在石英表面上的润湿性质,考察了表面活性剂类型及浓度对接触角的影响趋势,讨论了黏附张力和黏附功的变化规律.研究发现,两种表面活性剂在高能的石英表面的吸附造成石英-水的界面自由能(γsl)增大.C16PB通过弱相互作用随机吸附到石英表面,其增大γsl的能力与降低表面张力(γ1g)的能力相当,接触角(θ)随浓度变化不大.C16PC随体相浓度增大能够在石英表面通过静电作用形成定向排列的单分子层,而后在临界胶束浓度(cmc)附近形成双层结构,接触角随浓度变化的趋势可分为4个区域,并通过一个极大值.

The wetting behavior of quartz surface by aqueous solutions of cationic surfactant hexadecyl glycidyl ether ammonium chloride（C16PC） and zwitterionic surfactant hexadecyl glycidyl ether glycine betaine（C16PB） were investigated by the sessile drop analysis.The influence of surfactant type and concentration on contact angle were expounded and the change in adhesional tension and adhesion work were discussed.From obtained results it was appeared that an increase in quartz-water interface free emerge（γsl） due to the adsorption of both surfactants at the high-energy quartz interface.For C16PB,its adsorption at quartz surface can occur by weak interactions,which can be expected approximately equal ability of an increase in γsl and reduction of the surface tension of the liquid（γ1g）.As a result,there was little change of the contact angle with increasing bulk concentration.However,in the case of C16PC,the surfactant molecules can form a monolayer with alignment structure on the quartz surface through electrostatic interaction,as the bulk concentration increases,and then the bilayer formed when the concentration is near to critical micelle concentration（cmc）.The contact angle can be divided into four regions and passed through a maximum with increasing concentration.