Research On The Influence Of Nanostructure Of Machined Fused Quartz On The Pollutant Adsorption

As one of the most important components of the optical system,the fused quartz material plays an important role for device working normally and cost cutting in the optical system.However,plenty of nanostructures can be left on the surface or subsurface because the fused silica material is affected by the processing tool during the process of machining to be optical elements.The presence of these nanostructure makes it easy for organic pollutants in the environment to adsorb on its surface and permeate into subsurface and can be hard to be washed away,even with cleansers.Working under extreme conditions,the area which contains the pollutants can absorb more energy leading to a rising temperature and end up with explosions locally at these positons.Thus decrease the efficiency of optical system and its life-span and increase the prime cost at the same time.Therefore,it is necessary to carry out research on the pollutants absorption characteristics of nanostructures on fused quartz machined surface.Firstly,this dissertation describes the previously chosen for ensemble and potential function of Molecular Dynamics(MD)simulation and the process of modeling is introduced in detail.The characteristics of nano-machining is introduced form the cutting force,cutting energy,atomic motion,surface formation and chip formation mechanism,the differences between conventional maching process and the micro-nano processing are briefly analyzed.Secondly,the nano-cutting model was established using the molecular dynamics software and nano-cutting mechanism is ananlyzed.The changes of atom aggregation are the essential reason for influence of machining parameters on the machining process produces.The parameters discussed in this dissertation are the shape of tool,processing speed,processing depth and the fix method of substrate.Delphi software package is used to calculate the temperature distribution cloud map of the system,the effect of nanostructure processing procedure is discussed from the view of substrate temperature range during the different stage of the process.The Radial Distribution Function(RDF)before and after the process are compared and new phase is find out of the comparasion.The aggregation of atomic changes as the result of tool pressing before and after processing is analyzed.Thirdly,the effect of processing on the adsorption properties of water molecules is studied by establishing the relation model of nano-cutting and adsorption of water molecules.It is found that the the changes of atomic aggregation are the main reason for the effect that the processing parameters have on wettability change.Analysis from the atom scale found that the horizontal silicon oxygen rings on the machined surface have better adsorption ability than the inclined silicon oxygen ring on ideal surface,small density of silicon oxygen rings on the machined surface have better adsorption performance than the scattered rings on the ideal surface.Finally,the effect of processing on the adsorption properties of organic adsorption is studied by establishing the relation model of nano-cutting and adsorption of oil molecules,the adsorption rules of organic oil is studied.The adsorption ability differences between the two kinds of surface is obtained by comparing the oil density distribution on the ideal and machining surface which are under the same parameters.The adsorption properties of organic oil adsorption on nanostructure surface are summarized under the influence of different processing parameters.The adsorption rules is discussed at atomic level.MD simulation is appled to study the processing procedure of nanostructures on surface adsorption ability is analyzed.The influence of diverse parameters on the processing procedure,wettability and oil adsorption is stated in order to provide reference for micro-nano machining technology.