基于微纳米结构表面的浸润性及液滴蒸发行为的研究

发布时间：2018-05-27 02:38

本文选题：浸润性 + 液滴　；参考：《西北大学》2016年博士论文

【摘要】：浸润性是材料重要的基本属性之一,其用来描述两相界面接触时的状态。在人们生产生活中的众多方面都需要材料拥有特定的浸润性,这造就了人们对材料表面浸润性机理研究的动力。随着研究的进行,人们从自然界中的生物材料上发现,材料表面微纳米级别的结构是影响浸润性的一个重要因素。随着近几十年纳米材料的蓬勃发展,越来越多的人造微纳米结构被用于调节材料表面浸润性。而与浸润性密切关联的蒸发现象同样在众多领域中扮演着重要角色。由于人造微纳米结构表面的出现,原有的蒸发现象和理论都出现了新的变化。伴随着微纳米材料越来越广泛的应用,微纳米材料表面的浸润性和在其之上的蒸发现象的探究也显得越发重要和迫切。特别是蒸发与浸润性相耦合的研究领域还有很多待解决的问题。本论文旨在研究微纳米结构表面浸润性的调节,及以此为基础对液滴蒸发现象与材料表面结构及浸润性间的相互关系。文章内容主要包含以下几个方面：在第一章中,介绍了浸润性、微纳米结构及蒸发现象相关的基本概念,发展历史,以及三者之间的联系。在第二章中,我们首先从浸润性原理出发,以热激发的手段实现了纳米阵列材料表面浸润性大跨度的可控调节。并借助多种表征手段,将材料浸润性在这种情况下改变的内在机理予以了说明。最后建立起了材料浸润性与激发参数间的函数关系。在第三章中,我们首先从能量角度的估算开始,提出液体表面能可以破坏疏水涂层的假设。之后我们选择了特定的涂层材料和纳米线阵列制备了作为实验模型的疏水基底。在此基底上我们通过液滴蒸发实验验证了我们的假设。此后我们从能量与力学角度阐明了这一现象的机理,即表面张力主导的液滴接触线运动对表面疏水涂层的剥离作用机制。在第四章中,我们首先介绍了胶体液滴在纳米阵列材料上特殊的蒸发行为与沉积现象。之后从通过系统实验展示微纳结构上胶体颗粒的蒸发沉积结构及动力学演化过程,揭示了纳米阵列材料对蒸发液滴内部流动加速作用,以及纳米阵列材料在胶体液滴蒸发沉积过程中对胶体颗粒结晶的抑制作用。分析了微纳纹理化的结构所形成的特殊纳米弯月面所引起的毛细作用力对纳米颗粒在蒸发后期对最终自组织沉积结构的影响,同时讨论了微纳结构化基底与毛细力耦合作用下颗粒稳定性与运动形式。在第五章中,为研究扩散主导与对流主导两种不同机制下,蒸发对溶液从流体到固体转变过程中的稳定性,我们将高分子溶液作为研究对象。首先介绍了胶体液滴在蒸发过程中皮肤层的存在、产生机理及对蒸发产物结构的影响。之后先以喷雾蒸发手段探究了高分子微液滴在空中自由蒸发的结果与过程,后又基于纳米颗粒组成的超疏水基底研究了高分子液滴在超疏水状态下的蒸发。其中,通过系统地研究各项参数对蒸发产物结构的影响和对液滴在超疏水基底上的蒸发过程的分析,解释了各结构出现的机理,并得出了蒸发产物各结构触发条件的关系。
[Abstract]:Infiltration is one of the most important basic properties of material, which is used to describe the state of contact at the interface of two phases. In many aspects of people's production and life, the material needs a specific wettability, which makes people study the mechanism of the infiltration mechanism on the surface of the material. At present, the micro and nano structure of the material surface is an important factor affecting the wettability. With the rapid development of nanomaterials in recent decades, more and more artificial microstructures are used to adjust the surface wettability of materials. The evaporation phenomenon closely related to wettability also plays an important role in many fields. The appearance of the micro nano structure surface, the original evaporation phenomenon and the theory have appeared new changes. With the more and more extensive applications of micronanomaterials, the wettability of the surface of micronanomaterials and the evaporation phenomenon on it are becoming more and more important and urgent, especially in the field of coupling of evaporation and wettability. The purpose of this paper is to study the surface wettability of micro nanostructures and the relationship between droplet evaporation and the surface structure and wettability of materials. The main contents of this paper include the following aspects: in the first chapter, the fundamentals of infiltration, micro nanostructures and evaporation are introduced. In the second chapter, we first realized the controllable adjustment of the surface wettability of nanoscale array materials by means of thermal excitation in the second chapter, and explained the internal mechanism of the change of material wettability in this case by means of a variety of characterization methods. In the third chapter, we first start from the estimation of the energy angle, and propose the assumption that the liquid surface can destroy the hydrophobic coating. Then we choose a specific coating material and nanowire array to prepare the hydrophobic substrate as the test model. In the fourth chapter, we first introduce the special evaporation behavior of colloidal droplets on nanoscale materials. The deposition structure and dynamic evolution process of colloidal particles on micro nano structure were demonstrated by systematic experiment. The acceleration of nano array materials on the internal flow of evaporative droplets and the inhibition effect of nano array materials on the crystallization of colloid particles during the evaporation deposition of colloidal droplets were revealed. The effect of the capillary force on the final self organized deposition of nanoparticles in the later evaporation of the special nanoscale curved surface formed by the texture of a textured structure is also discussed. The particle stability and motion form under the coupling of the micronano structured substrate and the capillary force are discussed. In the fifth chapter, the study of diffusion dominated and convection dominated two Under different mechanisms, the stability of evaporation in the process of the solution from the fluid to the solid is taken as the research object. Firstly, the existence of the skin layer, the mechanism and the effect on the structure of the evaporation products during the evaporation process are introduced. The result and process of free evaporation, then based on the superhydrophobic substrate composed of nanoparticles, studied the evaporation of polymer droplets under the superhydrophobic state, and the mechanism of each structure was explained by the systematic study of the effects of various parameters on the structure of the evaporation products and the analysis of the evaporation over the superhydrophobic substrate. The relationship between the triggering conditions of each structure of evaporation products was obtained.
【学位授予单位】：西北大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：O552

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