Can we observe surface-induced intratubular flow with molecular dynamics simulations?

Tubular flows are common natural phenomena. Examples include blood and lymphatic flows in animals and xylem and phloem flows in plants. The main driving force for the flow is typically acknowledged to be a pressure gradient. Recently, an unexpected finding of an intratubular flow that occurs without the presence of a pressure gradient has been made (see for instance Li, Z. and Pollack, GH Surface-induced flow: A natural microscopic engine using infrared energy as fuel. Science Advances 6(19) 2020: eaba0941; DOI: 10.1126/sciadv.aba0941). This surprising discovery arose during the study of the properties of the so-called exclusion zone (EZ). The EZ is a region of structured aqueous solution next to various hydrophilic surfaces that effectively prevent the entry of particles and solutes. The molecular underpinning of the EZ-guided flow remains difficult to track. This project pursues the molecular investigation of intratubular flows in hydrogels with structure modelling and advanced molecular dynamics simulations at the nanoscale (Bonomi M, et al. Nature Methods 2019). This combination will offer new insight for the understanding of the molecular foundations underlying the generation of microscopic, surface-induced flow, fueled by infrared energy. In the long-term, we aim to translate such understanding into rules supporting the design of improved materials and nanotechnologies.