Biological Materials Science: Structural Biological Materials II
Sponsored by: TMS Functional Materials Division, TMS Structural Materials Division, TMS: Biomaterials Committee
Program Organizers: Po-Yu Chen, National Tsing Hua University; Francois Barthelat, McGill University; Michael Porter, Clemson University; Steven Naleway, University of Utah

Wednesday 8:30 AM
March 1, 2017
Room: Pacific 15
Location: Marriott Marquis Hotel

Session Chair: Francois Barthelat, McGill University; Wen Yang, ETH Zurich

8:30 AM  Invited
Bioinspired Design Strategies: Joanna McKittrick1; Steven Naleway2; Michael Frank1; Jay-Young Jung1; Frances Su1; Michael Porter3; 1University of California, San Diego; 2University of Utah; 3Clemson University
    Nature has provided a plethora of structural elements that can be incorporated into the design of synthetic materials and structures. The materials can be fabricated using the ice templating method, where the microstructures can be controlled intrinsically or extrinsically. 3D printing can be used to validate theoretical or computational concepts that are developed from the complex hierarchical structures. This presentation will review how the above can be used to create new, functional materials and structures. This work is supported by a Multi-University Research Initiative through the Air Force Office of Scientific Research (AFOSR-FA9550-15-1-0009).

9:00 AM  
Revisiting Laminated Glass Using Bio-inspired Architectures: Zhen Yin1; Francois Barthelat1; 1McGill University
    Laminated glass is made of alternating layers of glass and of soft, optically transparent polymers. This material is widely used in automotive and construction to contain glass shards in case of impact, but its actual resistance to impact is limited. Here we enhanced the performance of this material using bioinspired concepts. Although nature provides a few examples multilayered materials, most hard biological materials have more complex architectures including brick and mortar, cross-plies or Bouligand structures. We implemented some of these features by using laser engraving on laminated glass models made of borosilicate glass and Ethylene-vinyl acetate (EVA). While the deformation and fracture of basic laminated glass only involved a small fraction of polymers, the more complex architectured laminated glasses triggered specific and controlled deformation and fracture mechanisms that involved larger volumes of polymer. As a result, the bio-inspired architectures added to laminated glass significantly improved deformability, toughness and impact resistance.

9:20 AM  Invited
Impact and Wear Resistant Biological Composites: Insight to Next Generation Multifunctional Materials: Nicholas Yaraghi1; Steven Herrera1; Lessa Grunenfelder1; Nobphadon Suksangpanya2; David Restrepo2; Enrique Escobar de Obaldia2; C. Jeong2; Richard Wuhrer3; Pablo Zavattieri2; David Kisailus1; 1University of California Riverside; 2Purdue University; 3University of Western Sydney
    We investigate the hyper-mineralized combative dactyl club of mantis shrimp, highly aggressive marine crustaceans, and the heavily crystallized radular teeth of chitons, mollusks that graze on hard rock for algae. Our analyses of the mantis’ dactyl club reveal a multi-regional composite of either oriented crystalline hydroxyapatite or amorphous carbonated calcium phosphate, integrated with an architecture-specific chitinous organic matrix. We highlight regional ultrastructures and discuss their role in damage-tolerance and impact-resistance. Similarly, our analyses of the chiton teeth reveal a hierarchically arranged shell of organic-encased, highly oriented nanostructured magnetite rods surrounding a soft core of organic-rich iron phosphate, all connected to a flexible organic support. We discuss these ultrastructures to uncover structure–mechanical property relationships in abrasion resistant and damage tolerant teeth. Finally, we have fabricated biomimetic engineering composites with impact resistance that surpass the performance of composites found in many large commercial aircraft and are developing abrasion-resistant multifunctional coatings.

9:50 AM Break

10:10 AM  
Stretch-and-release Fabrication, Testing and Optimization of a Bioinspired Flexible Ceramic Armor: Roberto Martini1; Francois Barthelat1; 1McGill University
    Protective systems that are simultaneously hard to puncture and compliant in flexion are desirable, but difficult to achieve because hard materials are usually stiff. This conflict can be overcome by combining plates of a hard material with a softer substrate, a strategy which is widely found in natural armors such as fish scales and osteoderms. Here we fabricated and tested a flexible bioinspired armor based on overlapping ceramic scales. The fabrication protocol combines laser engraving and a stretch and release method which allows for fine tuning of the size and overlap of the scales. Compared to a continuous layer of uniform ceramic our fish-scale like armor is not only more compliant, but also more resistant to sharp puncture because of the reduced flexural span of the individual scales. Segmented protective systems therefore do not necessarily compromise resistance to puncture for flexibility, and important finding for the design of bio-inspired armor.

10:30 AM  
The Effect Moisture Content on Mechanical Properties of Lignin and Hemicellulose: Sina Youssefian1; Nima Rahbar1; 1Worcester Polytechnic Institute
    Here, we have utilized atomistic simulations to investigate the mechanical properties and mechanisms of interactions between hemicellulose, LCC and lignin, in the presence of water molecules. Our results suggest that hemicellulose exhibits better mechanical properties and lignin shows greater tendency to adhere to cellulose nanofibrils. Consequently, the role of hemicellulose found to be enhancing the mechanical properties and lignin found to be providing the strength of bamboo fibers. The abundance of Hbonds in hemicellulose chains is responsible for improving the mechanical behavior of LCC. The strong van der Waals forces between lignin molecules and cellulose nanofibrils are responsible for higher adhesion energy between LCC/cellulose nanofibrils. The amorphous regions of cellulose nanofibrils is the weakest interface in bamboo Microfibrils. In presence of water, the elastic modulus of lignin increases at low water content (less than 10% ) and decreases in higher water content, whereas the hemicellulose elastic modulus constantly decreases.

10:50 AM  
The Effect of Freezing, Thawing, and Drying on the Tensile Strength of Galleria mellonella Silk: Mary Glasper1; Jane Batcheller1; Andrew Keddie1; John Nychka1; 1University of Alberta
    Galleria mellonella (Lepidoptera: Pyralidae), the greater wax moth, is a major pest of stored or unattended beehive brood combs. The environment in which Galleria lives requires the continuous production of silk that is both strong and elastic; from the second instar onward, larvae produce large quantities of silk to construct feeding tubes which protect them from the bees. Continuous silk production differentiates Galleria from many other lepidopterans, where silk production is largely restricted to cocoon construction, and thus Galleria silk is a biological material worth investigating for many potential end-uses. To use this silk, the insects must first be euthanized and the cocoons dried to prevent spoiling in storage. The purpose of this study was to determine what effect the steps of freezing, thawing, and drying have on Galleria silk. The effects were evaluated visually using SEM and optical microscopy, and quantitatively using single-bave tensile strength tests.

11:10 AM  Invited
Lessons Learned from the Mighty Dactyl Club of the Mantis Shrimp: Nobphadon Suksangpanya1; Nicolas Guarin-Zapata1; Nick Yaraghi2; David Kisailus2; Pablo Zavattieri1; 1Purdue University; 2University of California Riverside
    The smashing Mantis Shrimp has been known for its heavily smashing blow creating the velocity and acceleration equivalent to a .22 caliber bullet with the forces up to 1.5 kilonewtons and the load-bearing part of its raptorial appendages, so-called dactyl club, having a capability of withstanding such tremendous forces. The focus of this research is on this extraordinary damage tolerant dactyl club. We carry out a combined analytical, computational and experimental investigation of the structure-function relationship of two critical regions of the dactyl club that exhibit unique architectures. The inner periodic region contains mainly a “flat” Bouligand structure (mineralized fiber layers stacked in a helicoidal arrangement); whereas the impact region reveals a sinusoidally-architectured Bouligand structure. This new type of architecture was found to be much more impact resistant than the flat Bouligand structure. Our investigation is mainly focused on the mechanics of these two different regions under different loading conditions.