Micro/Nano-Rheology of Thin and Thick Coatings of Functional Sol-Gel Hybrids

微/纳米压痕接触流变学的研究主要是为了：(A)建立弹塑性/粘弹性接触力学的理论框架，并将其应用于涂层/基材复合材料体系；(B)考察适合于研究弹塑性和粘弹性接触变形和流动的固体衬底上的溶胶-凝胶涂层的化学/物理条件；以及(C)应用本发明的新技术/纳米压痕流变学分析来原位探测在溶胶-凝胶工艺中缩合化学反应过程中形成的硅氧烷团簇和网络。本课题的主要研究成果如下：(1)对时变弹塑性和时变粘弹性压痕接触变形和流动的本构方程进行了理论研究，并将其推广到…。更多涉及涂层/基材复合系统。在有限元分析的基础上，对本文提出的理论框架进行了分析和数值研究。(2)设计并构建了一种新型的仪器化纳米压痕测试系统。该方法不仅适用于微纳尺度下与时间无关的弹性、塑性和弹塑性响应的研究，也适用于随时间变化的粘弹性和粘性响应的研究。(3)采用溶胶-凝胶法在钠钙玻璃板上制备有机-无机杂化薄膜(MeSiO_&lt；3/2&gt；和phsio_&lt；3/2&gt；)，用于纳米流变性测试。通过对前者的弹塑性分析和对后者的粘弹性分析，考察了在溶胶-凝胶过程中形成的硅氧烷链状网络结构随缩合反应的时间和温度的变化。结果表明，微/纳米压痕流变学对于表征涂层/基材体系不仅具有与时间无关的行为，而且还具有与时间相关的行为是非常有效的。较少

A research project on the micro/nano-indentation contact rheology had been intensively as well as extensively conducted for (a)developing theoretical frameworks of elastoplastic/viscoelastic contact mechanics, and its application to coating/substrate composites systems, (b)examining the chemical/physical conditions of sol-gel-derived coating films on a solid substrate that are appropriate for studying the elastoplastic and viscoelastic contact deformations and flows, and (c)applying the present novel techniques/analyses of nano-indentation rheology to in situ probing the siloxane clusters and networks that are evolved during the condensation chemical reaction in sol-gel processing. The major research results of the present project are summarized in what follows :(1)Theoretical considerations were made for the constitutive equations of indentation contact deformations and flows in the time-independent elastoplastic and the time-dependent viscoelastic regimes, and then they are extended … More to coating/substrate composite systems. Analytical/numerical studies were also conducted on the basis of finite element analyses to scrutinize the theoretical frameworks proposed in this research project.(2)A novel instrumented nano-indentation test system was designed and constructed. It is efficient for researches in micro/nano-regimes not only for the time-independent elastic, plastic, and elastoplastic responses, but also for the time-dependent viscoelastic and viscous responses.(3)Sol-gel-derived thin and thick organic-inorganic hybrid films (MeSiO_<3/2> and PhSiO_<3/2>) coated on a soda-lime glass plate were prescribed for nano-rheological testing. The molecular structures of siloxane chain networks that are evolved in sol-gel processing were examined in terms of the time and the temperature of the condensation reaction, through the elastoplastic analysis for the former hybrid and the viscoelastic for the latter. It was confirmed that the micro/nano-indentation rheology is very efficient for characterizing coating/substrate systems having not only time-independent, but time-dependent behaviors, as well. Less