Strengthened, conductivity-tunable, and low solvent-sensitive flexible conductive rubber films with a Zn2+-crosslinked one-body segregated network

A high-performance flexible conductive material based on cheap carboxymethyl chitosan (CMCS) and carboxylated styrene-butadiene rubber (XSBR) was fabricated via latex film-forming technique. Nano zinc oxide (ZnO) was introduced to react with CMCS, generating a Zn2+-crosslinked CMCS one-body segregated (Zn2+-COBS) network. Differing from reported conductive fillers with segregated structures, this Zn2+-COBS network was a continuous framework structure, which could be turned into conducting network by absorbing moisture. Superior tensile strength of 22.6 MPa was achieved with 30 wt% CMCS and 2.5 wt% ZnO owing to the reinforced concrete structure effect of Zn2+-COBS architecture. The order of volume resistance (Rv) of the films could be tailored between x 10(8) and x 10(4) Omega cm by changing the water content from 0 to similar to 20%, although at 20% water content the strength decreased to about 2 MPa. Particularly, the material with 30 wt% CMCS and 2.5 wt% ZnO achieved a Rv of 7.8 x 10(3) Omega cm with 18.7% water content. Thanks to the abundant hydrogen bonding interactions between CMCS chains, this special architecture provided a strong swelling restriction on the rubber matrix and dramatically improved the conducting stability of film in solvents. The R-t/R-0 in toluene, petroleum ether and anhydrous alcohol for 2 h were only 7.52, 1.35 and 1.47 for the films with a water content of 4.9%, 5.3% and 8.8%, respectively. These results demonstrate a promising method to fabricate an economical, conductivity-tunable, and flexural film material with potential applications in humidity detectors or in solvent environments.

Automated summary

A high-performance flexible conductive material was developed using cheap CMCS and XSBR, with added ZnO to create a Zn2+-COBS network for improved conductivity. The material exhibited superior tensile strength and adjustable volume resistance, showing better conductivity performance at higher water content, making it suitable for humidity detectors or solvent environments.