Fabrication Of Conductive Microfibers Based On Microfluidics For Flexible Electronics

Flexible electronics is a newly-developing technology,which means circuits or electronic components could still keep their corresponding functions during the free bending conditions.In recent years,along with the development of electronic materials research,flexible electronics has successfully integrated with electronics,material science,physics,and many other fields together,becoming one of the hot topic areas of interdisciplinary research.Compared with traditional solid-state electronics,flexible electronics shows great advantages in portability,biocompatibility,wearable mechanical stability,flexibility,and etc.Therefore,flexible electronics has achieved great progress in the next-generation electronic devices with remarkable performances and elastic mechanics response,including flexible health monitor,intelligent biochemical sensors,and smart flexible energy storage and collection device.In the infrastructure of various flexible electronic systems,microfibers play an important role in many industries,such as membrane textile and wearable devices,owing to their advantages of light weight,good mechanical flexibility and versatility.However,most current strategies for preparing conductive microfibers are only based on meeting some certain characteristics of flexible electronic systems,which is difficult to meet the actual needs of applications.Therefore,it is urgent to develop some novel technologies or other bio-inspired strategies to improve the performance of functional flexible electronic devices,which is of great significance to promote the development of flexible electronic field.Inspired by the silk spinning of spiders in nature,microfluidic technology has been developed to realize the function of controlling and manipulating fluids in microchannels,which has been considered as a powerful technology to manufacture flexible electronic systems.Additionally,by adjusting microfluidic parameters,including the choice of fluid phase and its viscosity as well as the flow velocity,microfibers with diverse geometrical shapes can be successfully prepared.In this paper,we realize the preparation of conductive microfibers based on microfluidic technology.Through the study of biophysical characteristics of microfibers,their potentials in the field of flexible electronics are revealed.The main research contents are as follows:(1)Based on the single-channel glass capillary microfluidic device,elastic MXene hydrogel microfiber was successfully prepared by combining the conductive two-dimensional material(MXene)with the dual-network biological hydrogel material.On the basis of the above microfluidic device,by introducing another embedded glass capillary channel,core-shell structured conductive microfibers could be fabricated in the form of straight and helical.In addition,microfibers with PEDOT encapsulation could be realized by adjusting the embedded glass capillary channel as theta glass capillary.By introducing another embedded glass capillary channel,elastic conductive polyurethane(PU)microfibers with multi carbon nanotubes(CNTs)cores could be fabricated.(2)On the basis of conductive microfibers fabricated from microfluidics,the variety of physical or biological properties were studied,including the electrical and mechanical performances of material itself.Meanwhile,dynamic mechanical changes of these conductive microfiber were investigated for the electrical response performance,which meant the weak mechanical changes could be inverted into easily monitoring electrical signals.Additionally,through several times of electrical stimulation,the repeatability of dynamic electrical response performance of conductive microfibers was demonstrated.The biological compatibility performance of microfibers was explored by co-culturing with cells.(3)Flexible electronic systems can be established based on the electrical,mechanical and biological properties of conductive microfiber materials prepared by microfluidics.Thanks to the electrical properties,effective conduction of current could be realized as wires,and the coreshell structure could avoid external interference to a certain extent.From the dynamic electrical response performances,practical applications in motion monitoring,gesture recognition,and temperature sensing were investigated.In addition,the application of flexible woven material in energy storage was studied through the capacitance characteristics of conductive microfiber materials.