Facile Fabrication of Microfluidic Chips for 3D Hydrodynamic Focusing and Wet Spinning of Polymeric Fibers.

Akin Gursoy,René M Rossi,Alexis Tello,Kongchang Wei,Fabien Sorin,Thijs Defraeye,Kamran Iranshahi,Efe Armagan,Luciano F Boesel,Claudio Toncelli

doi:10.3390/polym12030633

Abstract

Microfluidic wet spinning has gained increasing interest in recent years as an alternative to conventional wet spinning by offering higher control in fiber morphology and a gateway for the development of multi-material fibers. Conventionally, microfluidic chips used to create such fibers are fabricated by soft lithography, a method that requires both time and investment in necessary cleanroom facilities. Recently, additive manufacturing techniques were investigated for rapid and cost-efficient prototyping. However, these microfluidic devices are not yet matching the resolutions and tolerances offered by soft lithography. Herein, we report a facile and rapid method using selected arrays of hypodermic needles as templates within a silicone elastomer matrix. The produced microfluidic spinnerets display co-axially aligned circular channels. By simulation and flow experiments, we prove that these devices can maintain laminar flow conditions and achieve precise 3D hydrodynamic focusing. The devices were tested with a commercial polyurethane formulation to demonstrate that fibers with desired morphologies can be produced by varying the degree of hydrodynamic focusing. Thanks to the adaptability of this concept to different microfluidic spinneret designs—as well as to its transparency, ease of fabrication, and cost-efficient procedure—this device sets the ground for transferring microfluidic wet spinning towards industrial textile settings.

Highlights

Different from conventional wet spinning where the precipitation of polymer fibers occurs in coagulation baths, microfluidic wet spinning confines polymer and coagulant solutions within co-axial laminar flows
We demonstrated the capabilities of such a device in establishing 3D hydrodynamic
We demonstrated the capabilities of such a device in establishing 3D hydrodynamic the device for polymer fiber production by spinning a thermoplastic urethane fiber under different flow focusing by using fluid dynamics simulations as well as flow experiments

Summary

Introduction

Different from conventional wet spinning where the precipitation of polymer fibers occurs in coagulation baths, microfluidic wet spinning confines polymer and coagulant solutions within co-axial laminar flows. This technology permits a higher control of the diffusion interface amid the two laminar flows, allowing the solidification of polymer fibers in a more regulated manner [1]. Several studies have prompted microfluidic wet spinning of fibers featuring different mechanical properties and complex morphologies [2,3]. This was achieved by varying the hydrodynamic shear depending. Microfluidic spinnerets for this purpose should be able to establish

Methods

Results

Conclusion