Molecular Dynamics Simulation of Ice Crystal Growth Inhibition by Hexadecyl-trimethyl-ammonium Bromide
Molecular Dynamics Simulation of Ice Crystal Growth Inhibition by Hexadecyl-trimethyl-ammonium Bromide
复制标题
十六烷基三甲基溴化铵抑制冰晶生长的分子动力学模拟
DOI：
10.1021/acs.langmuir.8b01903
复制
发表时间：
2018
期刊：
影响因子：
3.9
通讯作者：
Kenji
中科院分区：
文献类型：
--
作者：
Shimazu;Naoya; Takaiwa;Daisuke; Suh;Donguk; Kawaguchi. Touru; Fuse;Takuya; Kaneko;Takashi; Yasuoka;Kenji
最近的实验发现十六烷基三甲基溴化铵（CTAB）具有优异的冰核抑制性能[J]。理论物理。化学。121年,6580]。抑制作用发生的机制尚不清楚。因此，采用分子动力学方法模拟了水/CTAB/冰体系的冰结晶过程。比较了基片[0001]、第一棱柱[101′0]和副棱柱面[112′0]在纯水体系中的冰结晶速率，其中基片棱柱面生长最慢，其次是第一棱柱面。当CTAB加入冰-液态水体系时，结晶明显受阻。即使当冰开始远离CTAB分子生长时，亲水的头也会在某个时候突出并被困在水/冰界面中。一旦CTAB的头部被包裹在前进的界面中，疏水体就会四处蠕动，破坏对冰生长至关重要的氢键网络的形成。当界面清除CTAB分子体的长度时，冰结晶以正常的速度恢复。综上所述，对冰生长的抑制是亲水性头部作为锚和疏水尾部的动态运动的结合，阻碍了冰生长的稳定氢键。
Recent experiments have found hexadecyl-trimethyl-ammonium bromide (CTAB) to have superior ice nucleation inhibition properties [J. Phys. Chem. B 121,6580]. The mechanism of how the inhibition takes place remains unclear. Therefore, molecular dynamics was used to simulate ice crystallization of a water/CTAB/ice system. The ice crystallization rate for a pure water system was compared for the basal [0001], first prism [101̅0], and secondary prism plane [112̅0], where the basal plane grew the slowest followed by the first prism plane. When CTAB was added to the ice–liquid water system, crystallization was clearly impeded. Even when ice starts growing away from the CTAB molecule, the hydrophilic head would at some point protrude and get caught in the water/ice interface. Once the head of the CTAB was encapsulated in the advancing interface, the hydrophobic body would wriggle around and disrupt the formation of hydrogen bond networks that are essential for ice growth. When the interface clears the length of the body of the CTAB molecule, ice crystallization resumes at its normal pace. In summary, the inhibition of ice growth is a combination of the hydrophilic head acting as an anchor and the dynamic motion of the hydrophobic tail hindering stable hydrogen bonding for ice growth.