Nanomechanics of Mechanically Active Polymers

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Nanomechanics of Mechanically Active PolymersPI: William P. King1, Co-PI: Ken Gall1,21George W. Woodruff School of Mechanical Engineering, 2School of Materials Science and Engineering, Georgia Institute of Technology, Atlanta, GA 30332Nanometer scale organic actuators perform critical functions in various biological systems. Although much research has characterized synthetic organic actuation at relatively large scales, it is highly desirable to reduce the size of present actuators to allow direct interaction with certain biological systems and facilitate integration with emerging nanosystems. Active polymer deformation at small scales would have applications in biology, medicine, and engineering. The goal of the proposed research is to investigate nanomechanics in advanced active polymer materials. The specific objectives are to: (1) Understand the fundamentals of nanometer-scale strain storage and recovery in shape memory polymers and liquid crystal elastomers using atomic force microscopy (AFM) and imprint lithography experiments. (2) Resolve the physical phenomena in the storage and recovery of nanometer-scale strains in shape memory polymers and liquid crystal elastomers using molecular dynamics modeling. (3) Use the research program as a vehicle to create a unique and exciting educational opportunity for students at all levels to learn about nanoscience and nanotechnology.The proposed research combines experimental and theoretical approaches and expertise in AFM, active polymers, and atomistic modeling. AFM impression experiments will be used to study the effects of deformation size-scale, temperature, and polymer structure on strain storage and recovery in shape memory polymers and light activated actuation in liquid crystal elastomers. Multi-scale molecular dynamics simulations will be used to ascertain operant deformation mechanisms in the materials and to help interpret results of AFM experiments. The experiments and simulations will be tightly coupled so experimental findings help to drive modeling studies and vice-versa. The research is driven by two technology test-beds; a nanopackage delivery system and an active biological scaffold. The intellectual merit of the research lies in the first-ever measurements and modeling of mechanically active polymers at nanometer scales. The research achieves broad impact through a fundamental advancement in the understanding of active polymers that will aid polymer scientists and engineers at all length scales. The research is the necessary first step in the rational design of engineered biomimetic systems capable of nanometer-scale energy storage, processing, and delivery. The research emphasizes the participation, education, and training of elementary school and high school students, undergraduates, graduate students, who will all benefit from exposure to nanoscience and nanotechnology research.