Micro Flow Study Of Liquid Crystal Polymer Injecting Molding Process

With the development of micro fluidic system,especially the development of the biochip and the chip lab technology,the micro flow measuring technology has attracted more and more attention of the researchers.Compared with the macro flow,the micro flow in micro-fluidic system is more various and complex,so the measuring technology of macro flow is not feasible to the micro flow.It is urgent to develop new measuring technology based on the characteristics of micro flow.In this thesis,we developed a new measuring technology special for the liquid crystalline micro flow induced by the change of the thermal field based on the micro-PIV technology.The achievements of this study can enrich the research method in micro-fluidic drive and control field and lay a solid foundation for the application of liquid crystalline backflow drive and control technology.The main contents of this thesis are as follows:(1)The design and manufacture of the key instruments of the measuring system.The temperature changing is the key factor to cause liquid crystalline micro flow,so the measuring system must control the temperature changing precisely.So firstly a low-voltage electric cooling-and-heating stage was designed and manufactured with semiconductor and 3D printing technology.The functions are: firstly,the process of heating,cooling and thermostatic can be controlled precisely;secondly,electric field can be applied to the sample.Compared with the similar products,the self-made stage can meet all the requirements of the measuring;(2)The hardware set up of the measuring system and measuring experiments.The hardware equipments including three parts: micro flow excitation part,the observation and data recording parts.The micro flow caused by the temperature changing was measured by the system.The measuring experiments was divided into two stage: firstly,the formation of large area of stable liquid crystalline defects;secondly,a large number of experimental data were obtained by measuring the micro flow caused by the interaction of the liquid crystalline defects;(3)The measuring result image processing part.This part is the software part of the measuring system,the velocity data of the micro flow could be obtained through theimage processing.The treatment process is: extract the gray level data from the specific image of the experimental video by MATLAB programming;put the gray level data into the micro flow equations,the tilt angle data of the liquid crystalline molecules and the velocity data could be achieved;(4)The theoretical verification of the measuring data.In this part the appearance and disappearance temperature of the liquid crystalline defects were verified by the method of molecular dynamic simulation.The software of Material Studio was used.(5)The control experiment of the liquid crystalline micro flow.On the basis of measuring micro flow successfully,the controlling experiment of the micro flow was conducted with the measuring system.The laser engraving machine was used to carve different patterns to the glass plates to control the position and intensity of the defects,and then micro flow.