Architectural scale biomimetic composites based on chitosan and alginate hydrogels

Thesis: S.B., Massachusetts Institute of Technology, Department of Materials Science and Engineering, June 2015.Cataloged from PDF version of thesis. "May 2015."Includes bibliographical references (pages 44-46).Developmental research and characterization was conducted on novel biomaterials for a larger project of product and architectural scale digital fabrication using natural bioplastics and hierarchical computational design carried out by the Mediated Matter team, led by Laia Mogas-Soldevila and Jorge Duro-Royo. Chitosan and alginate (among other natural polymers) are processed from shellfish waste and algae, respectively, and highly viscous solutions are extruded as a layer-by-layer printing material which dries into a solid, single material product with spatially variable functionality. Additional solid materials are added including cellulose microfibers and kaolinite platelets as volumetric aggregates, strengthening or stiffening aggregates, and as modes for directional properties. All materials used for aggregates, like that of the hydrogel matrices, were naturally sourced and recyclable. These composite materials were analyzed through microscopy and mechanical testing to begin to determine their agency in the aforementioned purposes. The most promising materials were selected and then discussed at length in an attempt to understand the factors behind ease of production, scalability, and potential for optimization, and as the research continues, they will be tested in the digital fabrication platform at the installation scale.by Daniel Lizardo.S.B