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采用分子动力学模拟方法对十二烷基磺丙基甜菜碱(SB12-3)在气/液界面微观聚集行为进行研究,模拟结果表明:SB12-3分子在气/液界面处紧密排列形成紧密单分子层界面膜,SB12-3亲水基团-N~+-(CH_2)_3-SO_3~--磺酸基与水分子间相互作用高于季氮离子与水分子间相互作用,水分子更易聚集与磺酸基周围,加入Ca~(2+)后磺酸基中SB12-3分子与水分子之间氢键数量基本保持不变,解释了SB12-3具有较强的耐盐性能;体系中加入Na~+和Ca~(2+)对亲水基团占有面积影响较小,SB12-3疏水链尾端碳原子灵活性与摆动空间序参数较小,有序性较好。
The molecular dynamics simulations were used to study the microscopic aggregation of dodecyl sulfopropyl betaine (SB12-3) at the gas / liquid interface. The simulation results show that the SB12-3 molecules are closely arranged at the gas / liquid interface At the monolayer interface, the interaction between the water-molecule and the water-molecule of the hydrophilic group -N ~ + - (CH_2) _3-SO_3 ~ -sulfonic acid group of SB12-3 is higher than that of the quaternary nitrogen ion- And the number of hydrogen bonds between the SB12-3 molecule and the water molecule in the sulfonic acid group after adding Ca2 + remained almost unchanged, which explained that SB12-3 had strong salt tolerance. The addition of Na ~ + and Ca ~ (2+) in the system has little influence on the occupied area of the hydrophilic groups, while the flexibility and swing space order parameters of the carbon atoms on the tail of SB12-3 hydrophobic chain are less and the orderliness is better.