Li Ting I N G, Olvera de la Cruz Monica
Department of Materials Science and Engineering, Northwestern University, Evanston, Illinois 60208, USA.
J Chem Phys. 2015 Dec 28;143(24):243156. doi: 10.1063/1.4938533.
Surface energy is a fundamental material property that determines important functions such as catalytic, sensing, and imaging properties. Over the past century, various experimental studies and models including the broken bond theory and Wulff construction have been developed to analyze surface free energies. However, it remains a challenge to measure or predict thermal fluctuation effects on surface energies. In particular, crystals of functionalized building blocks, such as self-assembling proteins and DNA-functionalized nanoparticles, assembled via the specific surface interactions of the building blocks, are highly sensitive to thermal fluctuations. In the case of DNA-functionalized nanoparticles, it has been shown that the crystals are formed as a result of thermally active hybridizations. We show here that the surface energy along different planes can be obtained from the ratio of hybridization events. The surface energy fluctuations in these systems are shown to bear a nearly linear correlation with the fluctuations in DNA hybridization events in the bulk. We further demonstrate that short DNA chains and high DNA loading increase the volume density of the DNA sticky ends. The relationship between thermally active hybridizations and surface energy found here can be used to aid the design of single crystals of functionalized colloids with active surface groups.
表面能是一种基本的材料属性，它决定了诸如催化、传感和成像特性等重要功能。在过去的一个世纪里，已经开展了各种实验研究并建立了包括断键理论和伍尔夫构造在内的模型来分析表面自由能。然而，测量或预测热涨落对表面能的影响仍然是一个挑战。特别是，通过构建单元的特定表面相互作用组装而成的功能化构建单元晶体，如自组装蛋白质和DNA功能化纳米颗粒，对热涨落高度敏感。就DNA功能化纳米颗粒而言，已经表明晶体是热活性杂交的结果。我们在此表明，沿不同平面的表面能可从杂交事件的比率中获得。这些系统中的表面能涨落与本体中DNA杂交事件的涨落呈现出近乎线性的相关性。我们进一步证明，短DNA链和高DNA负载量会增加DNA粘性末端的体积密度。此处发现的热活性杂交与表面能之间的关系可用于辅助设计具有活性表面基团的功能化胶体单晶。
