Continuous and high throughput production of alginate fibers using co-flow in a millifluidic T-junction

We present a new technique for continuous production of alginate fibers using off-the-shelf millifluidic components and syringe pumps. The components are quickly assembled to form a T-junction to deliver co-flowing streams of sodium alginate and calcium chloride allowing formation of hydrogel fibers in the exit channel. We vary the flow rates of the two streams, calcium chloride concentrations and length of exit channel and identify conditions where fibers of uniform and nonuniform thickness are produced. We find that uniform fibers can be produced at a maximum total flow rate of 10 mLmin(-1). As expected, for uniform fibers, we observe that the fiber diameter increases with increase in alginate solution flow rate, and we propose a simple model that predicts the fiber diameter as a function of flow rate ratio. We investigate the source of fiber nonuniformity and explain it using an empirical model that involves crosslinking time and gel strength. Our approach features easy device assembly and operation and enables continuous fiber production without clogging risks. Fiber production rates in the order of 10 mmin(-1) are achievable using our approach. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47120.