Polymer entanglement drives formation of fibers from stable liquid bridges of highly viscous dextran solutions

Liquid bridges have been studied for over 200 years due to their occurrence in many natural and industrial phenomena. Most studies focus on millimeter scale liquid bridges of Newtonian liquids. Here, reptation theory was used to explain the formation of 10 cm long liquid bridges of entangled polymer solutions, which subsequently stabilize into polymer fibers with tunable diameters between 3 and 20 mm. To control the fiber formation process, a horizontal single-fiber contact drawing system was constructed consisting of a motorized stage, a micro-needle, and a liquid filled reservoir. Analyzing the liquid bridge rupture statistics as a function of elongation speed, solution concentration and dextran molecular weight revealed that the fiber formation process was governed by a single timescale attributed to the relaxation of entanglements within the polymer solution. Further characterization revealed that more viscous solutions produced fibers of larger diameters due to secondary flow dynamics. Verification that protein additives such as type I collagen had minimal effect on fiber formation demonstrates the potential application in biomaterial fabrication.

Automated summary

Liquid bridges have been extensively studied for over 200 years, with recent research focusing on entangled polymer solutions forming long liquid bridges that stabilize into tunable polymer fibers. It was found that the formation process of these fibers is governed by a single timescale related to the relaxation of entanglements within the polymer solution. Additionally, more viscous solutions were observed to produce fibers with larger diameters due to secondary flow dynamics. Further experiments showed that protein additives like type I collagen have minimal effect on fiber formation, indicating potential applications in biomaterial fabrication.