Nacre crystal growth as a paradigm of island growth mode: Hydrophobic substrate is one of the keys to the biomineralization

Abstract

Nacre is a multilayered film material consisting of alternating layers of aragonitic tablets and organic membranes (OMs). However, at this time, no authors have discussed the growth mode of nacre from the perspective of the science of typical film materials. Here, for the first time, we focus on measuring the contact angles of the nacre growth surface (GS) using the contact angle meter. Additionally, we also investigate the GS's structure and phases using field emission scanning electron microscopy and X-ray diffractometer, respectively. We firstly found that: (1) The contact angles of the GS are always greater than 90°, with a maximum value of 113° and minimum value of 91°, indicating that the GS is hydrophobic. (2) The growth mode of GS is similar to the island growth mode (V-W) of the typical films. (3) The hydrophobicity of OMs plays an important role in the nucleation and growth of nacre. This research may provide new insights into the mechanism underlying nacre formation. In the field of thin-film, this conclusion will provide a new direction for the preparation and research of hydrophobic substrates, and a new idea for the development of thin-film technology.