Undergraduate Research that Sticks
I am a rising senior studying Polymer Science at the University of Southern Mississippi (USM). For the past two years at USM, I have worked in Professor Simon’s research group investigating the coassembly behavior of linear amphiphilic triblocks in the fabrication of polymer vesicles. Having worked in a polymer synthesis lab, I wanted to explore the bulk properties of polymers through an engineering focused research. My interests seemed a natural fit for the program in the School of Materials Engineering at Purdue University. This summer, I am studying the debonding mechanisms of rigid microparticles from elastomeric substrates under the mentorship of Professor Chelsea Davis and Professor David Bahr. While I am not technically a Purdue MSE undergrad, I have been enjoying the opportunity to get to know the School from an outsider’s perspective while I learn more about engineering research.
My SURF project is focused on understanding how to control the adhesion and detachment of rigid microspheres to soft polymer substrates. The insights gained from this project will benefit industries that require precision in powder and particulate handling. Energetic materials and active pharmaceutical ingredients are often manufactured and processed in small quantities of particles, so developing new methods for immobilizing them on a substrate, transporting them, and then releasing them in a controlled manner are necessary. I am studying the effects of applying a tensile deformation to the elastic substrate on the adhesion of a spherical particle to the substrate. With guidance from my graduate mentor, Naomi Deneke, a PhD candidate in Professor Davis’s group, I have built an experimental setup that is comprised of an optical microscope, a micromechanical tensile load frame, and a contact adhesion testing device. My experiments allow me to monitor the change in contact area between a spherical glass bead and a poly(dimethylsiloxane) (PDMS) substrate as the PDMS experiences a lateral strain. I measure the normal load and displacement of the bead as it is pushed into contact with the substrate and then pulled away. From this data, I can compare the work of adhesion values when PDMS is stretched to different strains. I am also investigating effects of the substrate modulus and the size of the particle on adhesion. So far, we have figured out that the work of adhesion decreases when we increase the amount of strain in the elastic substrate. Also, we have observed that the shape of the contact area changes when the substrate is stretched. These early fundamental results are teaching us exciting new approaches for how to manipulate particles simply by controlling the deformation of the adhesive substrate.
Besides these scientific insights, by working on this project, I have learned a new approach to conducting research. My problem-solving skills have been strengthened as I worked to discover the best method of organizing and assembling several instruments to get useful data. Overall, I have gotten an experience of what life is like as a graduate student, working as a full-time researcher this summer. I have relished my time as a SURF student at Purdue this summer and am excited to continue this path ahead. After my graduation in May 2020, I would like to pursue a doctoral degree in Materials Engineering, particularly studying polymers. Spending my summer at Purdue has not only given me the opportunity to do hands on experiments, but also has made me realize the vast array of research topics and how science can impact our lives. I was awestruck to hear Professor Kendra Erk talk about the usefulness of incorporating something as delicate as hydrogels into concrete as an internal curing agent, leading to a tougher structural material. One of the graduate students in the Davis research group demonstrated the formation of perfect wrinkles in a glassy thin film by subjecting it to varying stress environments, utilizing fundamental buckling mechanics to guide her experiments. Needless to say, my own project captivated me when I realized that multiple phenomena come into play when I simply bring two objects into contact with each other. This summer, I have learned to think and to expand my horizon of curiosity, which I believe will be of the greatest value as I continue my career as a researcher.
