Functional Soft Materials Designed Using Colloids and Interfaces at and Beyond Equilibrium PDF Download

Author: Xin Wang
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Languages : en
Pages : 0

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Book Description
Biological systems rely on complex, dynamic and reconfigurable structures to achieve functions that are essential for life, such as directed motion, transport of energy, synthesis and release of hormones to coordinate metabolism. They also operate beyond equilibrium to exchange information and matter with their environment. Inspired by nature, synthetic materials have been used to recapitulate functions of living systems, including the design of adaptive films/emulsions/vesicles that can reorganize and respond to external stimuli, and active matter that can convert energy from their surrounding environments into mechanical work. The research described in this dissertation explores physical principles for the design of various functional soft matter systems. First, I demonstrate the design of adaptive materials as sensors for amphiphiles and dynamical reaction pathways based on liquid crystals that output optical signals, through a tightly coordinated experimental and theoretical approach. The research is enabled by engineering dynamic and reconfigurable hierarchical emulsions and films via a combination of dynamic interfacial processes, including adsorption and desorption of analytes and the generation of interfacial tension gradients (Marangoni stresses). Second, I describe a progression of dynamic self-propelled motion of emulsion systems dictated by phase separation inside the emulsion droplets. Third, adaptive and active emulsion systems that respond to external analytes or chemical gradients and eject cargo are described. In particular, miniature soft machines that respond to external chemical gradients and autonomously eject cargo at a remote location are discussed. Fourth, I describe how advective flows and interfacial tensions can be designed to collect and sort microplastics. The materials systems developed in this dissertation leverage processes both at and beyond equilibrium in the context of adaptive and active matter. To achieve autonomously functioning soft machines, such as droplets and particles, we move beyond stimuli-responsive strategies, which still require intervention by the user or tight control of the environment, to explore the use of dissipative processes to create functional active matter. The strategy for microplastics removal and recycling presented here also develops foundational knowledge for a set of innovative technologies that have the potential to address societal needs on environmental issues facing our planet.