Functionalized carbon nanotube-cellulose nanocrystal (CNT-CNC) composite buckypaper via various methods for improved hydrophilicity performance and behavior

Abstract

Cellulose nanocrystals (CNCs) have inspired great interest in the research community over recent years due to their unique nanostructure and interesting properties such as their flexibility, excellent mechanical properties, and strong hydrogen bonding. These properties have led to it being used as reinforcement in mixtures with inorganic materials, with the resulting material displaying enhanced durability and improved mechanical properties. In this paper, we investigated improving dispersibility and stability by adding CNCs to multi-walled carbon nanotubes (MWCNTs) as reinforcement, and according to the characteristics of durability improvement and the interaction of chemical composition was measured the hydrophilicity of manufactured buckypapers (BPs) by various nanofluids. To improve their properties, the MWCNTs were functionalized using chemical methods such as oxidation or alkalization involving an acid mixture of concentrated solvents to build up carbonyl and hydroxyl functional groups with carboxylic acids. The composite structure of the obtained BPs was investigated by TEM and SEM analysis. The modified nanofluids were characterized using UV/Vis spectrophotometer, Raman, and FT-IR spectrum analysis. Contact angle (CA) measurements were used to determine the resulting BPs hydrophilicity, raw MWCNT BPs were found to be super-hydrophobic with a CA of 132.2 degrees (degrees), while the BP made from MWCNTs after the addition of and chemical treatment with CNCs achieved super-hydrophilic CAs ranging from 46.6 degrees to 81.3 degrees. Our testing has shown that BP made from MWCNTs can be improved by the addition of CNCs in terms of its nano-structure and morphological features; when compared to raw MWCNT BP, the frequent interactions between the constituent CNTs and CNCs lead to improved durability, dispersion, stability, and hydrophilicity due to the -OH structure created.