Kollipara Pavana Siddhartha, Lin Linhan, Zheng Yuebing
Walker Department of Mechanical Engineering, The University of Texas at Austin, Austin, TX, 78712, USA.
Materials Science & Engineering Program and Texas Materials Institute, The University of Texas at Austin, Austin, TX, 78712, USA.
J Phys Chem C Nanomater Interfaces. 2019 Sep 5;123(35):21639-21644. doi: 10.1021/acs.jpcc.9b06425. Epub 2019 Aug 8.
It has been well established that thermoelectric (TE) field can arise from different Soret coefficients of salt ions in the aqueous solution under constant temperature gradient. Despite their high relevance to cellular biology and particle manipulations, understanding and controlling of TE field in complex colloidal systems that involve micro/nanoparticles, salt ions and molecules have remained challenging. In such colloidal systems, the challenge arises from the thermal interactions with charged micro/nanoparticles that distort the TE field around the particles. Herein, we provide a framework for TE field in colloidal suspensions with various ions and surfactants at the single-nanoparticle level. In particular, we reveal the spatial variation of TE field around a dielectric particle under temperature gradient to determine the thermoelectric trapping force on the particle. Our theoretical results on the trapping force predicted from the TE force profile match well with the experimental opto-thermoelectric trapping stiffness of particles in the solutions where the temperature gradient was well-controlled by a laser beam. With their insight into TE field and force in complex systems, our framework and methodology can be extended to engineer the TE field for versatile opto-thermoelectric manipulations of arbitrarily shaped particles with non-uniform surface morphology and to advance the scientific research in cellular biology.
已经充分证实，在恒温梯度下，水溶液中盐离子不同的索雷特系数会产生热电（TE）场。尽管它们与细胞生物学和粒子操控高度相关，但在涉及微/纳米粒子、盐离子和分子的复杂胶体系统中，对TE场的理解和控制仍然具有挑战性。在这种胶体系统中，挑战源于与带电微/纳米粒子的热相互作用，这种相互作用会扭曲粒子周围的TE场。在此，我们提供了一个在单纳米粒子水平上研究含有各种离子和表面活性剂的胶体悬浮液中TE场的框架。特别是，我们揭示了温度梯度下电介质粒子周围TE场的空间变化，以确定粒子上的热电捕获力。我们根据TE力分布预测的捕获力理论结果，与通过激光束很好地控制温度梯度的溶液中粒子的实验光热电捕获刚度相匹配。凭借我们对复杂系统中TE场和力的深入理解，我们的框架和方法可以扩展，以设计TE场，用于对具有不均匀表面形态的任意形状粒子进行多功能光热电操控，并推动细胞生物学的科学研究。
