Bio-assembled nanocomposites in conch shells exhibit giant electret hysteresis.

Giant electric polarization (2000-4000 μC cm(-2)) is observed in natural conch shells. The nanolaminas and biopolymer layers of their unique hierarchical microstructures exhibit ferroelectret behavior and account for the observed polarization. Such huge polarization leads to extremely high pyroelectric coefficients, 2-3 orders of magnitude larger than those of conventional ferroelectric materials. The possibility of tailoring the giant polarization for various applications is considered.