Elastocapillary Dynamics During Wetting and Drying of Sheets and Fibers

Princeton University, Princeton NJ

Investigators

Abstract

1132835 Stone Surface tension plays a role in many industrial problems and natural phenomena; many of these involve significant elastic effects of the basic materials such as the surrounding substrates and/or porous matrices, e.g. textiles, hair, and filters are just some of the soft materials that readily change shape (and possibly function) when wet or dried. Although static problems involving the interplay between surface tension (capillarity), elasticity, and possibly other forces are well studied, there are very few studies of the dynamics of elastocapillarity, which is the subject of this proposal. Because of the breadth of applications that involve elastocapillary dynamics, spanning material science, and the biological and environmental sciences, we believe that this research area will yield new insights and applications. The research in this proposal is focused on characterizing, both experimentally and theoretically, two common geometries - sheets and fibers - and two common dynamical situations - spontaneous wetting and drying. In addition, we will study the dynamics of wetting and drying of a model soft porous material consisting of a fibrous matrix. In this way, we will provide a systematic, yet broad characterization of the dynamics of elastocapillary flow problems. The research described in this proposal may yield new insights such as whether there is an optimum drop size for wetting a fibrous medium and how the drying rate of a fibrous medium is influenced by the softness (elasticity) of the fibers. Broader impacts: In addition to publishing our findings in journals that span engineering, physics, and materials science, the PI will continue his multi-faceted outreach activities, including hosting visitors from different disciplines and educational institutions, engaging undergraduate students in research and giving talks at conferences, leading professional development activities for undergraduate, graduate, and postdoctoral colleagues, and participating in mentoring programs for young researchers from under-represented groups. Also, the PI has successfully incorporated research themes into "holiday" lectures for children and parents that he has given over the past 9 years and which he will continue to develop and present. Overall, the research will have a direct impact on our understanding of wetting and drying of common soft fibrous materials, which arises in a wide variety of industrial and natural systems.