Woodruff School of Mechanical Engineering
Living systems as design guides for tunable response and ultrafast motion
Dr. Symone Alexander
Georgia Tech School of Chemical and Biomolecular Engineering
Wednesday, February 12, 2020 at 11:00:00 AM
MRDC Building, Room 4211
From nanoscale to macroscale architectures, structured polymeric materials connect disciplines of physics, biology, and engineering and serve as a foundation for understanding the complex interactions leading to motion. As an NSF graduate research fellow, Dr. Alexander utilized transport phenomena in pinecones as bio-inspiration to design stimuli-responsive composites. Pinecones change shape in response to hydration using a bilayer structure composed of active and passive layers. To mimic this behavior, molecular gels are used to reinforce the passive layer and increase hydrophobicity, while electrospun nanofibers are used to increase swelling in the active layer and decrease the layer modulus. Additionally, switching from randomly oriented to aligned electrospun nanofibers enabled control over curvature, shape, and response rate. The two fiber networks were embedded in a single elastomer, forming a durable, seamless interface. With this body of work, fundamental design concepts in nature were used to expand the application of molecular gels in polymer composites, while introducing facile strategies to achieve tunable, hygromorphic actuator platforms. As an Eckert Postdoctoral Research Fellow, Dr. Alexander is investigating a tiny arachnid native to the Peruvian Amazon Rainforest known as the Slingshot Spider. This spider employs a conical 3-D web to achieve accelerations exceeding 1300 m/s2 without sustaining physiological harm. In this research, Dr. Alexander is investigating how slingshot spiders achieve ultrafast motion using polymeric materials, fundamental physics concepts, and engineering design, while sharing insight about the utility of this extraordinary prey capture strategy.
Dr. Symone Alexander is an Eckert Postdoctoral Research Fellow at Georgia Institute of Technology in the Department of Chemical and Biomolecular Engineering. She is currently leading investigations on extreme organismic biophysics with a focus on ultra-fast motion in nature in Prof. Saad Bhamla's research group. She earned her Ph.D. in Macromolecular Science and Engineering as an NSF Graduate Research Fellow at Case Western Reserve University, advised by Prof. LaShanda Korley. During her graduate career, she led research on the influence of high molecular weight polymers on self-assembling small molecules and how those networks can be utilized to generate responsive polymer composites. She obtained a B.S. in Chemical Engineering from Howard University in 2013, where she investigated DNA-polymer assemblies utilizing Atomic Force Microscopy under the advisement of Dr. Preethi Chandran and Dr. Joseph Cannon. Dr. Alexander recently served as the elected chair of the 2019 Polymers Gordon Research Seminar (GRS) and actively participates in science communication through her role as a social media contributor for the Biophysics Journal. She is a recipient of numerous awards and honors, including numerous fellowships, selection as a 2020 Emerging Leader by Georgia Tech Dept. of Mechanical Engineering, selection as a 2019 American Chemical Society Future Faculty Scholar (ACS PMSE), and being selected as a 2018 Rising Star in Chemical Engineering by the Massachusetts Institute of Technology (MIT).