Phase transitions and crystallization of DNA-coated colloids

非技术摘要胶体是悬浮在液体中的纳米和微米大小的球体。这项研究的目的是探索和开发方法来指导或编程，将这些颗粒组装成特定的有序晶体排列。最终目标是将由聚合物、玻璃、金属和半导体等不同材料制成的胶体悬浮在水(或其他液体)中，并使它们自我组装成预先编程的功能微观排列。这些应用很可能在光电子学、微流体、过滤和催化等技术中得到应用，在这些技术中，不同类型材料在微尺度上的精确排列是其功能的关键。研究小组将使用附着在不同纳米和微米颗粒上的DNA序列，这些DNA序列将用于编程微观胶体颗粒的自组装。该团队将研究这些粒子如何运动并动态地自我排列，以形成各种晶体结构，并将测试这种程序化组装如何发生的理论。这项研究将培训博士和博士后研究人员这些新兴的最先进的胶体自组装方法。技术摘要这个项目的目标是对支配DNA涂层胶体自组装和结晶的微观过程有一个基本的了解。这项工作利用了首席研究员实验室最近在为广泛的胶体材料创造新的DNA涂层方面取得的突破。研究小组将专注于单组分体系的结晶动力学，以及在时间和资源允许的情况下，双组分体系的结晶动力学。这些实验将主要使用光学显微镜和光散射来测量相分离的动力学，但也将使用电子显微镜和流变学。这些实验的目标是在微观(单个粒子)水平上涉及晶体形成的不同动力学过程，包括成核、调幅分解、扩散和退火。包覆DNA的胶体代表了先进材料自组装的新前沿。由于它们具有许多独特的性质，包括可编程的特定相互作用、依赖于温度的对势和空间波动的表面相互作用，它们提出了一些与自组装前沿相关的新的科学挑战，并修改了成核和生长、反常扩散和可编程定向扩散的经典机制。研究小组将开发量化模型来描述和理解他们的观察结果。

Non-technical abstractColloids are nano and micrometer sized spheres suspended in a liquid. The aim of this research is to explore and develop methods to direct, or program, the assembly of these particles into specific ordered crystalline arrangements. The ultimate goal is to take colloids made from diverse materials such as polymers, glasses, metals, and semiconductors, suspend them in a water (or some other liquid) and cause them to self-assemble into preprogrammed functional microscopic arrangements. The applications are likely to be in technologies as diverse as optoelectronics, microfluidics, filtration, and catalysis, where the precise arrangement of different types of materials on the microscale is key to their functionality. The research team will use DNA sequences attached to different nano and microparticles, which will be used to program the self-assembly of the microscopic colloidal particles. The team will investigate how these particles move and dynamically arrange themselves to form various crystalline structures and will test theories of how such programmed assembly occurs. The research will train doctoral and postdoctoral researchers in these emerging state-of-the-art methods of colloidal self-assembly.Technical abstractThe goal of this project is to develop a fundamental understanding of the microscopic processes that govern the self-assembly and crystallization of DNA-coated colloids. The work takes advantage of recent breakthroughs developed in the principal investigator's laboratory for creating new DNA coatings for a wide spectrum of colloidal materials. The research team will focus on the dynamics of crystallization in one-component and, as time and resources permit, two-component systems. The experiments will measure the dynamics of phase separation using optical microscopy and light scattering primarily, but will also employ electron microscopy and rheology. The experiments target the different dynamical processes involved in crystal formation at the microscopic (individual particle) level, including nucleation, spinodal decomposition, diffusion, and annealing. DNA-coated colloids represent a new frontier for the self-assembly of advanced materials. Because they possess a number of unique properties, including programmable specific interactions, temperature-dependent pair potentials, and spatially fluctuating surface interactions, they present a number of new scientific challenges related to the frontiers of self-assembly, and modify classical mechanisms of nucleation and growth, anomalous diffusion, and programmable directed diffusion. The research team will develop quantitative models to describe and understand their observations.