Reclined trend of alkyl chain of sodium dodecylbenzenesulfonate molecules induced by friction  

作　　者：Xianzhang WANG Yuan LIU Liran MA Xuefeng XU Yu TIAN 

机构地区：[1]State Key Laboratory of Tribology,Tsinghua University,Beijing 100084,China [2]School of Technology,Beijing Forestry University,Beijing 100083,China

出　　处：《Friction》2022年第9期1353-1364,共12页摩擦（英文版）

基　　金：The work was financially supported by the National Natural Science Foundation of China(Nos.51675297 and 51527901).

摘　　要：Surfactants tend to adsorb on the surface/interface mostly in a directional manner.The alkyl chain orientation and conformation order for molecular monolayers of sodium dodecylbenzenesulfonate(SDBS)at low concentrations are studied by using the sum frequency generation vibrational spectroscopy(SFG-VS).The molecular arrangement of the surfactants adsorbed at the solid/liquid interface is further investigated.It is found that the arrangement of the SDBS at the interface becomes relatively ordered with increasing bulk concentration.Meanwhile,the orientation angle reduces gradually,and the molecules tend to be upright state.In addition,the effect of friction on the conformation order and orientation angle are also analyzed.The intensity of the SDBS vibrational contraction peak becomes lower after friction,which indicates that the anion has a reorientation process at the interface.The arrangement of molecules becomes more disordered due to friction.The orientation angle increases slightly,which indicates the monolayer has an inclined trend relative to the lateral direction on the interface.A modified adsorption model considering friction effect is proposed.This work may provide a reference for the further study of adsorption mechanism and application of surfactants.

关 键 词：FRICTION lubricating film sum frequency generation(SFG) orientation angle conformation order 

分 类 号：TH117[机械工程—机械设计及理论]