Entropy-driven self-assembly of tethered Janus nanoparticles on a sphere  

作　　者：Guolong Zhu Yuming Wang Lijuan Gao Ziyang Xu Xuanyu Zhang Xiaobin Dai Lijun Dai Cuiling Hou Li-Tang Yan 

机构地区：[1]State Key Laboratory of Chemical Engineering,Department of Chemical Engineering,Tsinghua University,Beijing 100084,P.R.China

出　　处：《Fundamental Research》2021年第5期641-648,共8页自然科学基础研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(Grants No.22025302 and 21873053);L.T.Y.acknowledges financial support from the Ministry of Science and Technology of China(Grant No.2016YFA0202500).

摘　　要：Understanding the effect of curvature and topological frustration on self-assembly yields insight into the mechanistic details of the ordering of identical subunits in curved spaces,such as the assembly of viral capsids,growth of solid domains on vesicles,and the self-assembly of molecular monolayers.However,the self-assembly of nanoparticles with anisotropic surface topology and compartmentalization on curved surfaces remains elusive.By combining large-scale molecular simulations as well as theoretical analysis,we demonstrate here that the interplay among anisotropy,curvature,and chain conformation induces tethered Janus nanoparticles to self-assemble into diverse novel structures on a sphere,including binary nanocluster(C_(B)),trinary nanocluster(C_(T)),nanoribbon(R_(N))and hexagon with centered reverse(HR),which are mapped on a phase diagram related to the length asymmetry of tethered chains and Janus balance of the nanoparticles.The dynamical mechanism for the formation of these structure states is analyzed by examining the detailed kinetic pathways as well as free energy.We also show that the centered-reverse state is more prone to emerging around the topological defects,indicating the defect-enhanced entropy effect on a curved surface.Finally,the analytical model that rationalizes the regimes of these structure states is developed and fits simulations reasonably well,resulting in a mechanistic interpretation based on the order through entropy.Our findings shed light on curvature engineering as a versatile strategy to tailor the superstructures formed by anisotropic building blocks toward unique properties.

关 键 词：Curved surface Entropy-driven self-assembly Defect-enhanced entropy effect Topological defect Anisotropic particle 

分 类 号：O17[理学—数学]