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Humidity responsive materials sense, respond and adapt to the environment in response to changes in humidity. An important potential application of this material technology is the creation of “smart textiles” that facilitate moisture management in clothing. Materials used for clothing must have characteristics such as elasticity, washability and abrasion resistance, but smart textiles that have been demonstrated to date lack these characteristics. It is the need for improved materials that motivated the present study. Here, we developed spore-cellulose nanofiber composites (CNF) and spore-polyurethane (PU) composites, which are two biologically-based humidity-responsive materials that derive their high energy density humidity responsiveness from spores. We demonstrate the use of these hygromorphing materials for smart textiles by coupling the responsive materials to fabrics to create a textile that vents in humid environments and closes in dry environments. This material can be used in clothing to enable fast evaporation of sweat from the skin and improved comfort. Because the spore-CNF composite is not elastic stretchy or water resistant and therefore is undesirable for real world clothing applications, we also developed a stretchy spore-PU composite that is simultaneously humidity responsive, stretchy and water and abrasion resistant. In addition, we fabricated spore-PU based hygromorphing fabric bilayer actuators to create venting smart textiles with adaptive permeability properties that are compatible with clothing applications. These smart fabrics have the potential to improve the functionality and utility of garments, especially those intended for athleticwear, workwear and protective garments.

Thesis (M.S.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 1980. / MICROFICHE COPY AVAILABLE IN ARCHIVES AND ENGINEERING. / Bibliography: leaves 91-93. / by Byung Hoon Kim. / M.S.

In this dissertation, we introduce a framework for simulating the dynamics between liquid and thin structures, including the effects of buoyancy, drag, capillary cohesion, dripping, and diffusion. After introducing related works, Part I begins with a discussion on the interactions between Newtonian fluid and fabrics. In this discussion, we treat both the fluid and the fabrics as continuum media; thus, the physical model is built from mixture theory. In Part II, we discuss the interactions between Newtonian fluid and hairs. To have more detailed dynamics, we no longer treat the hairs as continuum media. Instead, we treat them as discrete Kirchhoff rods. To deal with the thin layer of liquid that clings to the hairs, we augment each hair strand with a height field representation, through which we introduce a new reduced-dimensional flow model to solve the motion of liquid along the longitudinal direction of each hair. In addition, we develop a faithful model for the hairs' cohesion induced by surface tension, where a penalty force is applied to simulate the collision and cohesion between hairs. To enable the discrete strands interact with continuum-based, shear-dependent liquid, in Part III, we develop models that account for the volume change of the liquid as it passes through strands and the momentum exchange between the strands and the liquid. Accordingly, we extend the reduced-dimensional flow model to simulate liquid with elastoviscoplastic behavior. Furthermore, we use a constraint-based model to replace the penalty-force model to handle contact, which enables an accurate simulation of the frictional and adhesive effects between wet strands. We also present a principled method to preserve the total momentum of a strand and its surface flow, as well as an analytic plastic flow approach for Herschel-Bulkley fluid that enables stable semi-implicit integration at larger time steps. We demonstrate a wide range of effects, including the challenging animation scenarios involving splashing, wringing, and colliding of wet clothes, as well as flipping of hair, animals shaking, spinning roller brushes from car washes being dunked in water, and intricate hair coalescence effects. For complex liquids, we explore a series of challenging scenarios, including strands interacting with oil paint, mud, cream, melted chocolate, and pasta sauce.