Colloquium Schedule

Colloquium: Thursday, December 7, 4:10 PM, Lewis Lab 316

Soft, Strong, Resilient: How Mussels Use Multiscale Structures, Fiber Reinforcement, and Dynamic Bonding to Adhere to Rocks Underwater

Megan Valentine

Associate Professor of Mechanical Engineering
University of California, Santa Barbara

Using marine mussels as a model organism, we explore the role of geometry and internal interfaces in controlling biological adhesion. We observe the dynamics of mussel plaques as they debond from glass using a custom built load frame with integrated dual view imaging capabilities. We previously found that the shape of the holdfast improves bond strength by an order of magnitude compared to other simple geometries and that mechanical yielding of the mussel plaque further improves the bond strength by ~100× as compared to the strength of the interfacial bonds. Moreover, we determined that a porous, heterogeneous network within the plaque gives rise to novel modes of load transfer within the material. Here, I will present new work exploring how cyclic loading of the holdfast affects plaque debonding. We find that multicycle loading decreases small-strain stiffness, but does not compromise the critical strength or maximum extension, as compared to plaques that are monotonically loaded to failure. Strain-dependent plastic damage, observed using scanning electron microscopy, does not appear to be reversible or repairable on hours-long timescales. However, our results suggest that a redundancy of load-bearing mechanisms contributes to plaque toughness in repeated loading. These experiments provide new insight into the physical origins of biomaterials properties, and suggest new avenues for design of biomimetic systems with enhanced properties.
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Physics and Astronomy Colloquia are usually scheduled for Thursdays at 4:10 PM in Lewis Lab room 316. Refreshments and snacks are available in the nearby coffee room at 3:45 PM.


Physics Colloquium Schedule for FALL 2017

Click on Title below for past or upcoming Announcements (where available), and Speaker name for website.        

August 31Wonpil ImLehigh UniversityMechanisms and Energetics of Protein/Peptide Interactions in Biological Membranes
September 7John RogersNorthwestern Univ.Soft, Biocompatible Optoelectronic Interfaces to the Brain
September 14Megan DeCesarLafayette CollegePulsar Searching and Timing with NANOGrav: Toward a Detection of the Gravitational-Wave Background
September 21Gunton Symposium-Symposium in Honor of Prof. James Gunton’s Contributions to Statistical Physics 
September 28David MaiulloRutgers Univ.Bringing Physics to Broadway
October 5Xiaoji XuLehigh UniversityMultimodal Nanoscale Infrared Microscopy with sub 10 nm Spatial Resolution
October 12Anderson JanottiUniv. of DelawareUnravelling the Role of Defects and Small Polarons in Wide-Band-Gap Oxide
October 19Mirjam CveticUniv. of Penn.Modern String Theory Confronts Particle Physics and Black Holes
October 26Steven Van SciverFlorida State U.
November 2Joern DunkelMITGeometrical Control of Microbial Fluids: From Bacterial Spin Lattices to Active Matter Logic
November 9Arjun YodhUniv. of Penn.Self-Assembling Temperature-Sensitive Colloids for Investigation of Phase-Transitions, Frustration,   and Glass Dynamics
November 16Jared Maxson Cornell Univ.
November 23No ColloquiumHappy Thanksgiving-
November 30Patrick ConnollyLehigh UniversityEarly Newtonian Approaches to Gravitational Attraction
December 7Megan ValentineUC Santa BarbaraSoft, Strong, Resilient: How Mussels Use Multiscale Structures, Fiber Reinforcement, and Dynamic Bonding to Adhere to Rocks Underwater
December 14No ColloquiumHappy Holidays-