# Improvement of reversible compressibility of ultralight carbon nanotube/carboxymethyl cellulose materials through hydrophobic surface treatment

## TL;DR

This paper shows that treating ultralight carbon nanotube/cellulose materials with hydrophobic agents improves their ability to bounce back after compression, even in humid conditions.

## Contribution

The study introduces hydrophobic surface treatment as a novel method to enhance the reversible compressibility of ultralight CNT/CMC materials.

## Key findings

- Hydrophobized CNT/CMC materials showed a 65% recovery rate under high humidity (80% RH).
- Surface treatment with silane coupling agents improved the material's mechanical resilience.
- The treatment conditions were optimized to affect microstructure and surface chemical properties.

## Abstract

The mechanical properties of ultralight materials are influenced by their constituent materials, internal porous structures, and surface states. The surface chemical state is particularly crucial for materials composed of hydrophilic polymers such as cellulose, where interactions with ambient water are significant. In this study, we report that the reversible compressibility of ultralight carbon nanotube (CNT)/carboxymethyl cellulose (CMC) materials can be enhanced by hydrophobic surface treatment with silane coupling agents. We examined the treatment conditions for hydrophobization and investigated their impact on the microstructure and surface chemical properties of the ultralight material. The hydrophobized ultralight CNT/CMC materials with a bulk density of 1.6 mg/cm3 demonstrated superior reversible compressibility, with a 65% recovery rate even under high humidity conditions (80% RH).

This study investigated the effect of surface functional groups on the reversible compressibility of ultralight materials and succeeded in producing samples with reversible compressibility even under high humidity.