Biomimetic In Situ Self-Assembly of Metal Nanoparticles into Hierarchical 3D Mesostructures: Synthesis, Analysis, and Prospects

Abstract

Studies of the properties of nano-, micro-, and macrostructures of natural materials such as wood, bone, seashells, and spider webs stimulated the development of a new field of materials science called "biomimetics" and "bioinspired materials". The subject of research is the processes of self-assembly of particles, leading to a hierarchical multiscale structure of the material and the search for answers to the fundamental challenge of materials science about the relationship between the composition−structure−properties−function of the material. The declared goal of research is to advance our understanding of multifunctional natural materials and to design artificial materials with increased functionality that mimic the principles of the structure of natural materials. Design of a multiscale structure of artificial material; creation of a composite material with a hierarchical structure, consisting of organic and inorganic components; manufacture of "smart" materials capable of adequately responding to certain external influences�this is the level of complexity that faces the problems along this path. The greatest challenge in manufacturing bioinspired materials is to design artificial structures with organizational complexity like their biological analogues and to control their properties through a hierarchical architecture. Currently, it is possible to achieve a given combination of nano-and microstructures of a polymer material, which ensures its superhydrophobic properties, through controlled polymerization. Another approach is to organize the process of self-assembly of colloidal particles to create a material with useful optical properties (opalescence, SERS). In this perspective, we briefly review approaches to solving these problems and consider in more detail the technique of biomimetic in situ self-assembly of metal nanoparticles for fabricating hierarchical 3D mesostructures by deposition of metal onto a cathode template from a solution under a programmable pulsed electric current. The developed methodology makes it possible to grow micrometer-sized mesostructures made of either ensembles of nanoparticles, woven nanowires, or nanoplates of regular metals (Cu, Ag, Zn), ferromagnets (Ni, Fe−Ni, Pd−Ni), superconductors (Pb−In, Pb−Bi, Pb−Sn), semiconductors (Bi 2 Se 3 , InSb), and composites. The obtained samples exhibit an embedded hierarchical structural order, intricate complexity of forms, and similarity with biological species, mushrooms, plants, and seashells (hence, biomimetics). We analyze the main factors affecting the result of directed assembly of particles and the prospects for the development of techniques for solving the problems of creating materials with increased functionality.