Research On The Preparation Of Microfluidic Channel Based On Electrospinning Near Field Direct Writing Technology

In recent years,microfluidic devices have shown strong market potential in biochips,micro-electromechanical systems,and optical applications.Traditional microfluidic devices are mainly prepared by methods such as photolithography and 3D printing,which have the problems of time-consuming,high cost,or low resolution.The manufacturing of high-precision microfluidic devices also has problems such as complicated processes,high costs and high experimental environment requirements,which limits its further promotion in the fields of industrial and scientific research.Therefore,this paper proposes a simple and economical fabrication method of microfluidic devices,mainly by using electrospinning near-field direct-write(NFDW)fiber mold to prepare PDMS microfluidic devices and in-depth study of its key preparation processes.It mainly focuses on four aspects to carry out in-depth research,as follows.Firstly,the controlled variable method was used to study the effects of needle diameter,needle temperature,and collector speed on the surface morphology of a single fiber and the stacking effect of different layers of fiber walls.Moreover,the effects of process parameters on jet deposition behavior and fiber morphology are revealed,which had be used to realize the manufacture of microfluidic devices with different aspect ratios.Furthermore,through the comparative experiments,it was found that adding the auxiliary heating device of the collector effectively strengthened the adhesion of the root fibers.After the above processes,a variety of complex patterned fiber wall structures were successfully prepared,providing a stable basis for the subsequent fabrication of microfluidic devices.Secondly,exploring the influence and evaluation of the array multi-needle EFIF on the solution NFDW.Three methods were used to prove macroscopically the electric field interference(EFIF)between the array multi-needle,and the stress of the charged microelements in the jet process was analyzed to explain why the existing of EFIF.Moreover,Combined with COMSOL simulation,a multi-needle NFDW electric field distribution model was established,and the influence of the needle geometry parameters on the electric field distribution and intensity was analyzed.A quantitative evaluation method was proposed between the geometric parameters of the array needles and the effect of EFIF.Therefore,the suitable structure of array needle was selected for subsequent fabrication of microfluidic devices.Thirdly,the preparation process of the two-needle and single-needle solution NFDW orientation fibers was discussed.Orthogonal experiments were used to select the key parameters affecting the quality of the two-needle solution NFDW,and to explore the effect of each key parameter on the fiber diameter.Then the effect of EFIF between needles on fiber deposition was effectively reduced combining with the NFDW method of parallel arrangement of two needles.At the same time,the control variable method was used to select the suitable parameters for the stable preparation of the submicron fiber mold with a single needle,which provides a process basis for the subsequent preparation of high-resolution microfluidic devices.Finally,the fabrication of PDMS microfluidic devices and the application research of the laminar flow and microdroplet generation of T-shaped and cross-shaped microfluidic devices were carried out respectively,basing on the melt near-field direct write PCL master.Furthermore,the core steps of PDMS microfluidic device fabrication and the key processes of laminar flow and droplet generation were determined through comparative experiments.Then,the single-needle and double-needle solution NFDW PEO fiber mold were used to prepare a higher-resolution microfluidic device on the PDMS.It further proves the applicability and potential of electrospinning NFDW technology in the manufacture of microfluidic devices.