胶体粒子比原子大得多，且粒子间的相互作用容易调节，这使得胶体成为一个从时间尺度和空间尺度上均高度放大的研究凝聚态物质的模型体系，该体系中无序到有序的结晶和相变过程的研究，有助于深化对晶体生长规律的认识。通过环境因素控制胶体粒子之间的相互作用，可以有效调控胶体体系的结晶过程，对于深入理解胶体晶体结晶动力学规律、晶体结构和稳定性的影响因素，以及利用胶体结晶构建具有特定功能新材料等方面均具有重要意义。基于此，本文开展了壁面曲率、蒸发、耗散引力和温度场等环境因素对胶体晶体结晶过程的影响规律的研究，主要的研究内容和成果可以概括如下：

1、研究了壁面曲率对胶体晶体壁面生长的影响规律并给出了相应的机理分析。通过反射光谱测量了不同曲率壁面的胶体体系在结晶过程中结构参数的演变，发现不同曲率壁面下的结构参数显示出不同程度的振荡特性，表明晶体状态、尺寸和数量的波动存在差异。对于不同曲率壁面的胶体晶体稳定性，从晶体生长过程中弹性能和界面能的竞争进行了机理分析：当晶体弹性能小于界面能时，晶体可以稳定存在；当晶体弹性能等于界面能时，晶体会从弯曲壁面脱落，随后又会重新在弯曲壁面处生长，从而导致结构参数的波动现象。此外，胶体粒子浓度不会影响晶体的稳定性，但是会影响晶粒尺寸和晶粒数量。

2、系统研究了胶体体系在毛细管蒸发过程中完整的结构转变过程和浓度演变过程。针对初始状态为无序、体心立方和面心立方等不同结构的胶体体系，通过蒸发诱导的结构转变过程，可以快速得到无序-有序相转变的临界结晶浓度和体心立方胶体晶体向面心立方胶体晶体转变的浓度范围，对于确定胶体悬浮液在不同浓度下的相区具有重要的参考意义。此外，研究结果表明三种胶体体系蒸发过程中的浓度演变规律是一致的，根据粒子浓度的变化可将悬浮液划分为四个区：密堆积区、过渡区I、初始状态区和过渡区II。通过耦合蒸发、扩散和对流影响，建立了胶体悬浮液在毛细管中蒸发的物理模型，且模型计算的数值结果和实验测量结果基本吻合，进一步验证了该模型的有效性和可靠性。

3、基于单粒子分辨率的原位显微观察研究了耗散引力下的胶体晶体成核和生长过程。胶体晶体成核过程符合经典成核理论，且实验测量的临界晶核尺寸和理论计算结果基本一致。通过结晶度和晶体尺寸定量研究了胶体晶体的生长过程，发现晶体生长速率和Wilson-Frenkel理论结果基本吻合。此外，详细探讨了粒子浓度和高分子浓度对胶体体系结晶过程的影响和调控机制。增加粒子浓度和高分子浓度都会促进胶体的结晶，但是过高的粒子浓度导致聚集体的形成，反而不利于晶体生长；此外，过高的高分子浓度导致悬浮液粘度增加，也不利于晶体生长。因此，只有在合适的参数条件下胶体才可自发结晶。

4、在微通道内研究温度场对胶体体系结晶过程的影响。针对微通道中存在高分子的胶体体系，保持微通道两侧恒定的温度差，可基于热泳效应控制胶体粒子定向运动，实现了热泳作用下胶体体系从无序到有序的结晶过程。与耗散引力下的结晶过程不同，温度场通过对粒子的定向调控进而控制胶体体系结晶的空间位置分布，可以使原本不能自组装形成胶体晶体的体系结晶，且最终形成的晶体可以保持很好的稳定性。对于可自组装形成胶体晶体的体系，温度场调控形成的晶体的结晶度和晶粒尺寸均显著增大。此外，系统研究了粒子浓度、高分子浓度和温度场等参数对胶体体系结晶过程的影响，基于显微观察和定量分析发现粒子浓度主要影响晶体尺寸；温度场会影响胶体晶体结晶度和晶体尺寸；而高分子浓度的增加会增大耗散引力，但是同时又增加体系的粘度，因而在较低的高分子浓度范围内，浓度增大会促进胶体晶体的形成；而在较高的浓度范围内，浓度增大反而会阻碍胶体晶体的形成。因此，只有满足一定的参数条件，才可以通过温度场有效促进胶体的结晶过程。

Colloidal particles are much larger than atoms, and the interactions between particles are easily regulated, which makes it become an ideal model system with enlarged temporal and spatial scale for studying condensed matter. The study of the crystallization and phase transition from disorder to order in the colloidal system is helpful to deepen the understanding of crystal growth law. By controlling the interactions between particles by environmental factors, the crystallization process of the colloidal system can be effectively regulated. It is of great significance to understand the crystallization kinetics, crystals structure, crystals stability and in the application to form new materials with specific functions. Based on this, we studied the influence of environmental factors such as wall curvature, evaporation, depletion interaction and temperature field on the crystallization process of colloidal crystals. The main research contents and results are as follows:

1. The influence of wall curvature on the crystallization process of colloidal crystals was studied systematically and the corresponding mechanism was analyzed. The evolution of structural parameters of the colloidal systems inside different curvature walls during crystallization process was determined by the reflection spectrum. It was found that the structural parameters showed different degrees of fluctuation properties, indicating the fluctuation of crystal state, size and quantity was different. The mechanism about the crystals stability is analyzed from the competition between elastic energy and interfacial energy. When the elastic energy of crystals is less than the interfacial energy, the crystals can exist stably. When the elastic energy of crystals is equal to the interfacial energy, the crystals will fall off from the curved wall and then grow back on the curved wall again, which leads to the fluctuation of structural parameters. In addition, the particles concentration does not affect the crystals stability, but does affect the grain size and grain number.

2. The complete structure transformation and concentration evolution of colloidal suspension during drying process in the tube were systematically studied. Through the evaporation induced crystallization process of disordered suspension, bcc suspension and fcc suspension, we can quickly obtain the critical crystallization concentration from the disordered-ordered transition and the concentration range from bcc-fcc transition, which has important reference value for determining the phase region of colloidal suspension at different concentrations. In addition, the concentration evolution law of three colloidal suspensions during drying process is consistent. According to the difference of particle concentration, the suspension can be divided into four regions, namely, the close packed region, transition region I, initial concentration region and transition region II. By coupling the effects of evaporation, diffusion and convection, we established an evaporation model of colloidal suspension in the tube, and the numerical results calculated by the model are in good agreement with the experimental results, which further proves the validity and reliability of the model.

3. The nucleation and growth processes of colloidal crystals under depletion interaction were studied based on in situ microscopic observation at single particle resolution. The nucleation process of colloidal crystals accords with the classical nucleation theory, and the critical nucleation size measured by experiment is basically consistent with the theoretical calculation results. The growth process of colloidal crystals was quantitatively studied by crystallinity and crystal size, and it was found that the crystal growth rate was basically consistent with the results of Wilson-Frenkel theory. In addition, the influence and regulation mechanism of particle concentration and polymer concentration on crystallization process of colloid system were discussed in detail. Increasing particle concentration and polymer concentration can promote the crystallization, but too high particle concentration leads to the formation of aggregates, which is not conducive to crystal growth; too high polymer concentration leads to the increase of suspension viscosity and is also not conducive to crystal growth. Therefore, colloidal suspension can spontaneously crystallize only under appropriate parameters.

4. The influence of temperature field on the crystallization process of colloidal suspension was studied in the microchannel. For the colloidal suspension with polymer in the microchannel, by keeping a constant temperature gradient on both sides of the microchannel, the crystallization process of colloidal suspension from disorder to order is realized based on the directional movement of the colloidal particles controlled by thermophoresis. Different from the crystallization process under depletion interaction, the temperature field controls the spatial position distribution of the colloidal crystals through directional regulation of the particles, which can crystallize suspensions that cannot self-assemble to form crystals, and the final formed crystals can maintain high stability. For the suspensions that can self-assemble to form crystals, the crystallinity and crystals size of colloidal crystals formed by temperature field regulation are greatly improved. In addition, the effects of particle concentration, polymer concentration and temperature field on the crystallization process of colloidal suspensions were systematically studied. Based on microscopic observation and quantitative analysis, it was found that particle concentration mainly affects the crystal size. The temperature field affects the crystallinity and crystals size. The increase of polymer concentration will increase the depletion interaction, but at the same time increase the viscosity of the suspension, so in the lower polymer concentration range, the increase of the concentration will promote the formation of colloidal crystals; but in the higher concentration range, the increase of concentration will hinder the formation of colloidal crystals. Therefore, the crystallization process of colloidal suspension can be effectively promoted by temperature field only if certain parameter conditions are met.