MMAE Seminar by Oluwaseyi Balogun: Viscoelastic Characterization of Biofilms and Soft Materials based on Optical Coherence Elastography

Armour College of Engineering’s Department of Mechanical, Materials, and Aerospace Engineering will welcome Oluwaseyi Balogun, an associate professor in the Departments of Civil and Environmental Engineering and Mechanical Engineering at Northwestern University, to present a lecture, “Viscoelastic Characterization of Biofilms and Soft Materials Based on Optical Coherence Elastography” on March 24 from 3:30–4:30 p.m. 

The seminar is open to the public. Contact Elena Magnus at magnus@iit.edu for the seminar details and a link to join.

Abstract

Quantitative characterization of viscoelastic properties in biofilms and other soft materials are crucial to understanding the origin of their dynamic heterogeneous architecture, mechanical stability, and mechanical responses to external stimuli. The optical coherence elastography (OCE) technique has emerged as a powerful nondestructive characterization tool that relies on low coherence interferometry for the measurement of elastic wave propagation in transparent media. In this lecture, Balogun will present a frequency domain OCE approach that facilitates measurement of the dispersion relation of guided transverse waves in soft transparent materials. Balogun will discuss the numerical modeling approach that we adopted to predict the dispersion relation of viscoelastic transverse wave modes in flat plates, curved plates, and semi-infinite substrates, subjected to different boundary conditions. The model provides a useful tool to study the sensitivity of the wave speed to various properties—including viscoelastic properties, hydrostatic pressure, thickness, curvature, and density—for inverse analysis of mechanical properties, and to select experimental parameters for optimal sensitivity. Balogun will present experimental results and numerical calculations that demonstrate how Balogun’s research group has applied the combination of the modeling approach and the frequency domain OCE measurements to characterize the viscoelastic properties of various hydrogels and environmental biofilms, and the hydrostatic pressure-dependent mechanical properties of corneal tissue phantoms.

Biography

Balogun is an associate professor in the Departments of Civil and Environmental Engineering and Mechanical Engineering at Northwestern University. He received the Ph.D. degree in mechanical engineering from Boston University in 2006 and completed post-doctorate fellowships in the materials science and engineering department at the Johns Hopkins University and the Engineering Directorate at the Lawrence Livermore National Laboratory before joining the faculty at Northwestern University. Balogun directs an interdisciplinary research group that focuses on developing optical methods for quantitative characterization of elastic and viscoelastic properties, elastic stress wave propagation studies, and novel scanning probe microscopy methods for nanoscale heat transport and near-field optical measurements in materials. He is a member of the IEEE UFFC and IEEE Nanotechnology societies and a 2020 and 2021 Distinguished Lecturer recipient from the IEEE Nanotechnology Council.