Crack‐Induced Superelastic, Strength‐Tunable Carbon Nanotube Sponges

Abstract

Lightweight strong aerogels have many applications, but they suffer from the trade‐off between key mechanical properties, and it remains challenging to realize superelastic aerogels simultaneously possessing high strength and excellent structural recovery. Herein, a strategy to overcome such a problem by designing a carbon nanotube (CNT)‐based aerogel consisting of flexible‐rigid core‐shell structure, which achieve a combination of excellent properties including superelasticity (complete recovery at 90%), high strength (over 12 MPa at 90%) and wide tunability (from 101 kPa to 4.5 MPa at 50% strain), is presented. It is found that the outer rigid but brittle amorphous carbon shells crosslink the CNT cores and crack into orderly distributed segments during the first compression cycle, while the flexible CNT cores ensure the integrity of the overall skeleton and tolerance to large deformation. This designed CNT composite sponges exhibit overall superior mechanical properties than previously reported foams/aerogels, and due to such unique crack‐induced superelasticity mechanism, potential applications such as pressure sensors with wide‐range tailored sensitivity and high‐performance energy absorbers have been developed. This flexible‐rigid core‐shell synergia may provide further insight for tunable high‐strength aerogel design and innovative applications.

The Interface Strengthening of Multi-Walled Carbon Nanotubes/Polylactic Acid Composites via the In-Loop Hybrid Manufacturing Method

“…Its utilization in Fused Filament Fabrication (FFF) not only addresses concerns related to environmental pollution, but also leads to the creation of eco-friendly nanocomposites capable of biodegradation into harmless byproducts under standard degradation conditions [41,42]. Meanwhile, multi-walled carbon nanotubes (MWCNTs) are recognized for their exceptional potential in enhancing interlaminar properties, attributed to their high strength modulus and the advantageous characteristics of being high-aspect-ratio fillers [43,44]. This study involved PLA sourced from Shenzhen Creality 3D Technology Co., Ltd. (Shenzhen, China), demonstrating an average tensile strength of 57.8 MPa and an elastic modulus of 3.15 GPa.…”

Wet-Stable Lamellar Wood Sponge with High Elasticity and Fatigue Resistance Enabled by Chemical Cross-Linking

“…As a class of lightweight material with a highly porous threedimensional (3D) network structure, aerogels or foams hold great promise in various applications, including thermal insulation, 1−3 pollutant adsorption, 4,5 catalyst support, 6 strain/pressure sensors, 7−9 and energy storage. 10,11 So far, various aerogel materials have been developed from diverse building blocks such as silica, 12−14 graphene oxide, 7,15,16 carbon nanotubes (CNTs), 17,18 and synthetic polymers. 3,19 Nevertheless, the mechanical fragility of silica aerogels and environmental concerns associated with the use of synthetic polymers as well as the high cost of emerging carbon aerogels are motivating the increasing exploitation of sustainable biomass-based aerogels.…”

“…As a class of lightweight material with a highly porous three-dimensional (3D) network structure, aerogels or foams hold great promise in various applications, including thermal insulation, − pollutant adsorption, , catalyst support, strain/pressure sensors, − and energy storage. , So far, various aerogel materials have been developed from diverse building blocks such as silica, − graphene oxide, ,, carbon nanotubes (CNTs), , and synthetic polymers. , Nevertheless, the mechanical fragility of silica aerogels and environmental concerns associated with the use of synthetic polymers as well as the high cost of emerging carbon aerogels are motivating the increasing exploitation of sustainable biomass-based aerogels. Among them, nanocellulose-based aerogels using abundant and sustainable cellulose as the raw material have gained significant interest owing to their high porosity and large specific surface area (SSA) coupled with the excellent properties of cellulose itself. − Nanocellulose aerogels are often fabricated based on a bottom-up approach, which requires the disassembly of plant cell walls into cellulose nanofibrils followed by structural reassembly into aerogels.…”

Recyclable Wearable Sensor Based on Tough, Self-Healing, Adhesive Polyurethane Elastomer for Human Motion Monitoring

“…These unique characteristics have accelerated their extensive development in various fields, including healthcare monitoring/diagnostic devices, − electronic skin, − soft robotics, and human motion detection. , The principle underlying the sensing mechanism typically involves the change in electrical resistance in conductive elastomers caused by mechanical deformation. The conductive elastomers used in these sensors include conductive sponges, hydrogels, , thin films, , and fibers . Thin sensor films are often prepared by combining flexible elastomers with conductive materials through various composite techniques. − Commonly used conductive fillers include carbon nanotubes (CNTs), − silver nanowires, MXene, − and graphene. , The widespread use of electronic devices such as strain sensors has led to an increasingly severe problem of electronic waste.…”