Osmotic propulsion:: The osmotic motor
Osmotic propulsion:: The osmotic motor
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DOI：
10.1103/physrevlett.100.158303
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发表时间：
2008-04-18
影响因子：
8.6
通讯作者：
Brady, John F.
中科院分区：
文献类型：
--
作者：
Cordova-Figueroa, Ubaldo M.;Brady, John F.
本文提出了一种胶体粒子-渗透马达-浸入分散液中的自推进模型。由表面化学反应引起的浴颗粒的非平衡浓度在马达上产生渗透压不平衡，导致其移动。反应速度与扩散速度的比率决定了用于计算马达上的驱动力的浴粒子分布，并且从浴粒子分布确定自诱导渗透速度。对于慢反应，自推进与反应速度成正比。当表面反应超过扩散时，渗透速度不能超过浴颗粒的扩散速度。这些功能不同浴颗粒体积分数和电机尺寸的影响进行了讨论。理论预测相比，布朗动力学模拟。
A model for self-propulsion of a colloidal particle-the osmotic motor-immersed in a dispersion of "bath" particles is presented. The nonequilibrium concentration of bath particles induced by a surface chemical reaction creates an osmotic pressure imbalance on the motor causing it to move. The ratio of the speed of reaction to that of diffusion governs the bath particle distribution which is employed to calculate the driving force on the motor, and from which the self-induced osmotic velocity is determined. For slow reactions, the self-propulsion is proportional to the reaction velocity. When surface reaction dominates over diffusion the osmotic velocity cannot exceed the diffusive speed of the bath particles. Implications of these features for different bath particle volume fractions and motor sizes are discussed. Theoretical predictions are compared with Brownian dynamics simulations.