Reduction of structural hierarchy translates into variable influence on the performance of boron nitride aerogel

Jingjing Pan,Jingyang Wang

doi:10.1016/j.isci.2021.102251

Abstract

SummaryThe rise of ceramic aerogel offers traditional ceramics a new window. Alongside the emerging prospects, what is open to explore includes the elegant design of a ceramic aerogel with tailorable inner organizations, what would occur when complex hierarchy exists in such an already intricate system, and how the properties get influenced as the complexity fades. Borrowing the wisdom from supramolecular world, we exquisitely transform BN aerogel from a complex hierarchy to a flatten microstructure based on solvent-induced morphology switch of its supramolecular precursor gel. Such reduction in structural hierarchy has insignificant effect on the thermal conductivity (∼0.027 W/(m·K)) but shifts the wettability from hydrophobicity to hydrophilicity and occasions nearly 3-fold difference in ion adsorption rate, as exemplified by lead ions. This work may promote the understanding of special hierarchy existing in delicate systems and inspire other attempts to harness the functionality of aerogels by manipulating structural hierarchy.

Highlights

Nature excels in assembling similar building units into various biological systems, in which different levels of organization and complexity translate to versatile functions
What is open to explore includes the elegant design of a ceramic aerogel with tailorable inner organizations, what would occur when complex hierarchy exists in such an already intricate system, and how the properties get influenced as the complexity fades
Borrowing the wisdom from supramolecular world, we exquisitely transform boron nitride (BN) aerogel from a complex hierarchy to a flatten microstructure based on solvent-induced morphology switch of its supramolecular precursor gel

Summary

Introduction

Nature excels in assembling similar building units into various biological systems, in which different levels of organization and complexity translate to versatile functions. As a ubiquitous phenomenon in nature, molecular assembly contributes to the rise of supramolecular chemistry, a realm inspiring the design of intricate and functional architectures in artificial systems (Dumele et al, 2020; Leclercq et al, 2019; Mako et al, 2019; Meneghin et al, 2020). As the ‘‘glue’’ of supramolecular chemistry, a variety of non-covalent interactions (e.g., hydrogen bonds, charge interactions, and coordination) have been utilized for the organization of small components into fascinating systems with various dimensions (Chakrabarty et al, 2011). Other supramolecular architectures, maintained by other non-covalent forces, such as hydrogen bonding (Bui et al, 2020) or pi-pi stacking (Deng et al, 2020), are primary examples.

Methods

Results

Discussion

Conclusion