| This study reports on the development of a test platform (TP), which not only overcomes the limitations of the previously reported test platforms but is also a versatile tool that can be used to systematically study the tribology of MEMS surfaces.;The designs, actuation procedures and modeling of the various (i.e., seven types of) microinstruments included in the Test Platform are explained in detail in this study. The details of the key features of all the (seven types of) microinstruments are successfully highlighted in this study. Additionally, some of the microinstruments developed in this study are convincingly shown to overcome some of the limitations of the previously reported corresponding microinstruments.;Further, the investigation conducted to study the effect of surface topography reports the successful use of a dodecanethiol-capped gold nanoparticle-based surface texturing technique for tailoring the topographies of the surfaces (in-plane as well as sidewall) of five Test Platform chips. Additionally, it reports the successful investigation of six Test Platform chips (five textured using the dodecanethiol-capped gold nanoparticle-based surface texturing technique and one untextured (control)) conducted to understand the effect that the surface topography of a surface has on its tribological (i.e., stiction and friction) characteristics. The surface topographies of the surfaces of each of the six Test Platform chips investigated in this study are characterized qualitatively using SEM and quantitatively using AFM. The quantitative characterization of the surface topographies of the surfaces of the six Test Platform chips investigated in this study is used to quantify them in terms of two measurable parameters, namely, the rms roughness and the surface coverage of the interacting asperities present on the surface. Further, in order to understand the effects that the surface topography of a MEMS surface has on its stiction and friction characteristics, three important tribological properties of the surfaces of each of the six Test Platform chips investigated in this study, which are the apparent work of adhesion of the in-plane surfaces, the apparent work of adhesion of the sidewall surfaces and the engineering coefficient of static friction of the sidewall surfaces, are determined. The tribological characterization of the surfaces of the six Test Platform chips investigated in this study provided an experimental confirmation of the already believed theory that the friction experienced by contacting MEMS surfaces shows a strong dependence on the stiction experienced by them. Additionally, it indicated that both the micro-scale as well as the nano-scale topographies of a surface have a strong influence on its stiction and friction characteristics.;In order to mathematically correlate the surface topography of a surface with its stiction and friction characteristics, a dimensionless parameter called Tribotopography number (i.e., tautopo) is formulated in this study. Further, the Tribotopography number is successfully used to develop two mathematical correlations, one between the surface topography of a surface and its apparent work of adhesion, and the other between the surface topography of a surface and the friction experienced by it. In order to use the two mathematical correlations developed in this study for a particular type of surface, the value of index alpha, which is the index of the denominator of the fraction that represents the Tribotopography number, for that type of surface must be determined first. The value of index alpha for silicon-type surfaces (i.e., surfaces, whose tribological behaviours are governed by the same type of interfacial forces that govern the tribological behaviour of silicon surfaces) is determined in this study. This study also reports an analysis (i.e., experimental validation), which substantiates the validities of the two mathematical correlations developed to correlate the surface topography of a surface with its stiction and friction characteristics, respectively. Additionally, it also discusses the constraints, under which, the two mathematical correlations are valid. Lastly, the study reports the results of the investigation conducted to determine the influence of the geometry of the contact interface on the effect that the surface topographies of the surfaces forming the interface have on its tribological characteristics. (Abstract shortened by UMI.). |
