Aerogels for Biomedical, Energy and Sensing Applications

Abstract

The term aerogel is used for unique solid-state structures composed of three-dimensional (3D) interconnected networks filled with a huge amount of air. These air-filled pores enhance the physicochemical properties and the structural characteristics in macroscale as well as integrate typical characteristics of aerogels, e.g., low density, high porosity and some specific properties of their constituents. These characteristics equip aerogels for highly sensitive and highly selective sensing and energy materials, e.g., biosensors, gas sensors, pressure and strain sensors, supercapacitors, catalysts and ion batteries, etc. In recent years, considerable research efforts are devoted towards the applications of aerogels and promising results have been achieved and reported. In this thematic issue, ground-breaking and recent advances in the field of biomedical, energy and sensing are presented and discussed in detail. In addition, some other perspectives and recent challenges for the synthesis of high performance and low-cost aerogels and their applications are also summarized.

Emerging Trends in Nanotechnology: Aerogel-Based Materials for Biomedical Applications

“…Silanes are not commercially used to produce silica aerogels due to their higher cost and hazardous effects. However, for large scale manufacturing and practicability, sodium silicate is employed as a low-cost precursor in the synthesizing of silica aerogel [ 8 ].…”

“…As a result, ambient drying, modified super critical drying, and freeze drying (lyophilization) were employed. Unfortunately, it was difficult to entirely retain the gel’s microstructure under the drying conditions; thus, damage frequently happened [ 8 ]. Additionally, although there has been substantial advancement in the design and biological analysis of aerogels, additional work is still required to address the difficulties in the commercialization and clinical application of this complex class of materials.…”

“…Following that, important efforts were made to simplify the synthesis methods, particularly drying to achieve a low-cost and simple synthesis of aerogel. This paved the way for a wide range of aerogel to be used in various fields of application due to their open structure and lightweight [ 5 , 7 , 8 ]. To improve aerogel performance, significant growth in the emergence of future aerogel with varied physicochemical features and functional abilities is required [ 9 , 10 ].…”

Valorization of Starch to Biobased Materials: A Review

“…Aerogel is a solid, ultra-lightweight substance with high porosity and other exceptional features [ 180 ]. It consists of a three-dimensional and very porous network created from organic, inorganic, or mixed precursors utilizing a sol-gel approach paired with quick-drying technology to extract the liquid in an alcogel and replace it with another liquid [ 181 , 182 ]. However, in a more generic term, any non-fluid colloidal network or polymer network that is enlarged across its entire volume by a fluid could be referred to as aerogels.…”

Ultralight, Elastic, Hybrid Aerogel for Flexible/Wearable Piezoresistive Sensor and Solid–Solid/Gas–Solid Coupled Triboelectric Nanogenerator

“…The unique 3D porous structures of aerogels provide high porosity, ultralow density, and high specific surface area. [ 15 , 16 , 17 ] Conductive, compressible, and elastic aerogels have been considered as excellent candidates for fabricating flexible/wearable devices [ 18 , 19 , 20 , 21 ] such as piezoresistive sensors, [ 15 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ] and energy harvesting devices. [ 30 , 31 , 32 , 33 , 34 , 35 , 36 , 37 , 38 ] The flexible and compress 3D porous structure of aerogels can provide large numbers of adjustable contact areas which can modulate the electrical resistance under the external pressure.…”