Microfluidic elaboration of polymer microfibers from miscible phases: Effect of operating and material parameters on fiber diameter

Abstract

Background: fiber diameter is one of the most important morphological parameters which drives the applications of microfibers. This creates a need for the development of processes capable of producing a large variety of microfibers with a given diameter. To this regards, microfluidic spinning has recently emerged as an outstanding and simple technique for the production of micro-and nanofibers with controllable size and morphology.Methods: herein, microfibers were produced from (macro)monomers or prepolymers (core phase) by in situ photoirradiation using a capillary-based microfluidic device and a miscible sheath phase of various viscosity. The effects of the flow rate of both phases as well as the viscosity of the sheath fluid, the capillary dimensions and the monomer volume fraction in core phase were thoroughly studied.Significant findings: by calculating the capillary number ratio from the ratios of sheath to core flow rate and viscosity, an empirical relationship which perfectly predicts the microfiber diameter as a function of monomer volume fraction, the capillary number ratio and capillary inner diameter but independent of its outer diameter is extracted. This result paves the way to the continuousflow production of microfibers with well-controlled morphological characteristics.

Microfluidic Janus fibers with dual thermoresponsive behavior for thermoactuation

“…The side-by-side capillary-based microfluidic system previously reported [31] was used to prepare the thermoresponsive Janus fibers. Thermoresponsive Janus fibers, in which one part consisted of thermoresponsive polymer and the other one of non-thermoresponsive polymer, were produced using two core phases and one sheath phase (Φ sheath ).…”

“…Herein, we report the microfluidic preparation of actuators based on tunable thermoresponsive Janus fibers. Microfluidic spinning using a side-by-side capillary-based device offers the possibility to control various features of the fibers including their diameter, [31] their morphology (Janus and Hecate), [32] but also the composition of the fibers as they can be produced from pre-existing polymers or by photopolymerization of monomers during the fiber process. These Janus fibers were produced to afford fibers with one part being thermoresponsive starting from a monomer known to form polymers exhibiting a LCST-type behavior, and the second one non-thermoresponsive as depicted in Fig.…”

Simultaneous photo-induced polymerization and surface modification by microfluidic spinning to produce functionalized polymer microfibers: the effect of their surface modification on cell adhesion

“…UV-induced photopolymerization is an interesting choice to produce hydrogel-based microparticles 34 and microfibers. 35 Studies have been recently reported in the literature about producing and controlling the diameters and morphologies of fibers and particles using microfluidics. 36 But to the best of our knowledge, no work has described yet the use of microfluidics for the simultaneous production and surface modification of microfibers and particles.…”

Production of Janus/Hecate microfibers by microfluidic photopolymerization and evaluation of their potential in dye removal

“…19 Fibers produced by microfluidic spinning relying on immiscible fluids provide access to jetting conditions only in a very narrow range of flow rates to obtain fibers and thus limits the use of multiple core phases due to the existence of very different interfacial tensions. [20][21][22] Reports using purely miscible core and sheath phases describe the preparation of only single and Janus fibers based on alginate, [23][24][25][26] and also hollow 27 and mosaicked 24 fibers from poly(ethylene glycol) diacrylate until now. However, the preparation of Janus fibers, fibers with a side-by-side arrangement joined at the interface with two parts of different composition offering the possibility to develop materials with unique properties (e.g.…”

“…The width and therefore the volume of each part of the fiber increased with an increase in the flow rate of the respective monomer as we reported for single fibers. 26 Due to the faster diffusion of the less viscous core phase into Φ sheath , the corresponding part of the Janus fiber had a larger diameter ( i.e. TPGDA).…”