Study On Wax Electrostatic Printing For Fabrication Of Paper-Based Microfluidic Chips

Recently,microfluidic paper-based analytical devices??PADs?have been widely concerned in life sciences,food testing,,environmental monitoring,and other fields for their advantages of low cost,low consumption,ease of handling,portability,and environmental friendliness.Although scientists have studied ?PADs in depth and developed a variety of manufacturing methods,their development is still at an initial stage.How to manufacture ?PADs at a low cost,high efficiency,and in large quantities remains to be solved.It impedes the commercialization of ?PADs.In this paper,we developed a method that can rapidly manufacture ?PADs via electrostatic atomization technology and wax.On this basis,we deposited nanofiber membranes via electrospinning to replace paper,and fabricated 3D-?PADs by electrostatic printing.The specific works are summarized as follows:1.A electrostatic atomization device was developed to realize the wax printing,and the effects of voltage and heating temperature on the wax atomization were explored.The voltage of the electric field can directly affect the atomization mode of wax and the diameter of the droplets.Increasing the temperature can effectively reduce the diameter of the droplet.The Taylor cone shape,atomization mode and particle size of broken droplets under different electric field voltages and liquid properties were simulated to verify the experimental results via FLUENT.2.The influence of collecting distance,voltage and moving speed of collector plate on the wax printing was investigated.Reducing collection distance can increase print quality.The voltage needs to be matched with the moving speed of the collection plate to achieve the best printing effect.After orthogonal test,the best printing parameters of wax were found:heating temperature 100?,collecting distance 3mm,electric field voltage 5kV,and collecting plate moving speed 2.5mmls.3.The infiltration of paraffin on the paper was studied,and an ion concentration analysis device was fabricated based on paper.The experimental results show that the device can measure the concentration of Fe³⁺ in the range of 0.001?0.09mol/L via colorimetric method.4.Nanofibers were deposited by electrospinning to replace paper.A nanofiber-based 3D microfluidic chip was fabricated by depositing multiple film layers and printing and printing a wax pattern on each layer of film.Based on this method,a three-dimensional analysis device was developed to measure ion concentration.The results prove that it can quantitatively determine Fe³⁺ within the concentration range of 0.001?0.09mol/L.5.The differences between polyimide film and filter paper in the analysis rate,porosity and mechanical properties were compared.The results show that the polyimide film has higher resolution and higher elongation,but paper has greater porosity and can withstand more tensile stress.In this paper,we developed a new fabrication method of pPADs that can quickly spray wax onto a substrate to form flow channels.The method has the advantages of low manufacturing cost,high processing efficiency and simple operation.It is favorable for promoting the commercial manufacture of ?PADs.