Optimization of Biomimetic Oyster Cement for Commercial Applications

Polymer modified cement (PMC) is a composite material formed by incorporating polymers into cement. This improves various mechanical properties of cement, such as its flexibility, adhesion, and toughness, providing solutions to a wide range of engineering challenges. Looking to nature for inspiration, oysters produce biological cement to build extensive reef communities underwater. Previous studies have shown this cement is composed of 12% organics (peptides, carbohydrates, and lipids) and 85% calcium carbonate (CaCO3), with the remainder being water. The organic matrix is mostly uncharacterized, with previous studies showing signs of phosphate-based moieties.

This thesis applies oyster cement chemistry to commercial cement, to create a biomimetic PMC system that uses phosphate-functionalized polymers to increase adhesion and compression strength. This polymer and CaCO3 system is optimized through a series of ladder studies, tested against commercial benchmarks, and eventually incorporated into commercial mortar mix. This leads to a 300% increase in compressive strength and a 700% increase in adhesive strength on wetted substrates.

This thesis also includes the preliminary results of characterization of the chemical adhesive of poison ivy (Toxicodendron radicans) aerial rootlets using histological staining methods and fluorescence microscopy. Although unrelated to the main subject of this thesis, the Wilker lab had never performed tests and staining procedures for the characterizations described. This thesis memorialized the work performed for reference to future students in the lab who will perform similar testing.