Elastic modulus of biopolymer matrix in nacre measured using coupled atomic force microscopy bending and inverse finite element techniques

A novel approach combining the atomic force microscopy probing of nacre biopolymer strand and the inverse finite element analysis has been used to directly measure the elastic modulus of nacre biopolymer matrix. An elastic modulus of 11 ± 3 GPa was determined for the first time from the direct measurement of the nacre biopolymer matrix. This property is essential for a fundamental understanding of the roles that the biopolymer matrix plays in nacre's strengthening and toughening, and provides guidelines in selecting engineering polymers for biomimetic materials design and fabrication. Such coupled experimental and modeling techniques should find more applications in studying the mechanical behavior of biological materials.

► Modulus of nacre biopolymer was directly measured using AFM and inverse FEM.
► An elastic modulus of 10.57 ± 2.56 GPa was determined for nacre biopolymer matrix.
► New approach developed in this study is useful for testing of biological materials.