Research On The Fabrication Of Microchannels And The Interface Morphology Of Two Immiscible Fluids In Microchannels

This paper introduces the selection of the metal organic compounds and reductantsin the chemical reaction system and explores key parameters of the microchannel of thelaboratory preparation, including soft lithography, PDMS curing and bondingparameters. It also makes a study of the interface morphology of two immiscible fluidsin microchannels. The main researches and achievements are as follows:The metal organic compound, copper oleate, is selected and prepared successfully.Studies on the reducibility of sodium hypophosphite, sodium citrate and ascorbic acid tocopper oleate were carried out by means of a series of comparison experiments underthe macroscopic conditions, and the reduction products of the reaction of oleic acidcopper solution and sodium hypophosphite were analyzed by XRD.It studies the influence of the UV light source power and the length of exposuretime on the quality of the soft lithography by means of a series of check experiments,finding the best soft lithography parameters under the condition of near field exposure.PDMS and the curing agent were uniformly mixed at a mass ratio of10:1, stewing for1h and curing for90min under the condition of120℃. An analysis is made on theeffects of different oxygen flow rate and processing time on bonding, and the bestbonding parameters are found. The height of the microchannels on the PDMS wascharacterized by the step profiler to be5.1μm. After the treatment of such plasma asoxygen, the static contact angle of water on the glass surface decreased from58.21°to41.47°, and from116°down to16°on the PDMS surface, and the surfacehydrophilicity was improved.The PDMS subsidence in the channel reserves was the reason why the fluids didnot flow in microchannels, and the solution of this problem was to remove the reservesmechanically. The speed of the oil phase promoting the water phase under certainconditions was determined. The interface morphologies of the two phases in themicrochannels were observed, including finger-shaped flow, drop-shaped flow andpinning phenomenon and the cause of their formations was that the lipophilic of thePDMS walls was not uniform.