Enhancing the dispersibility of multiwalled carbon nanotubes within starch-based films by the use of ionic surfactants

The incorporation of carbon-based nanomaterials into biopolymer matrix, to provide mechanical reinforcement and to obtain electrically conductive bionanocomposites, requires the homogeneous dispersion of the fillers. Herein, it is investigated the influence of surfactant structures on the dispersibility of multiwalled carbon nanotubes (MWNT) within starch matrix. Three different ionic surfactants, sodium dodecyl sulphate (SDS), cetyltrimethylammonium bromide (CTAB) and sodium cholate (SC), are employed to disperse the MWNT. Films with MWNT-SC show better dispersibility and an increase of about 75% of tensile strength and 60% of Young's modulus compared with films using MWNT-SDS and MWNT-CTAB. Nevertheless, MWNT functionalized with CTAB impart the highest values of antioxidant activity (scavenging activity around 30% in 1.5 h) and electrical conductivity (sigma =14.75 S/m) to starch matrix. The properties of starch-based films can be tailored according to the physical adsorption of each surfactant on MWNT surface and/or the interfacial interaction of the surfactant with starch chains.

Automated summary

This study investigates the influence of different ionic surfactants on the dispersibility of multiwalled carbon nanotubes (MWNT) within a starch matrix. Films with MWNT-SC show the best dispersibility and have the highest tensile strength and Young's modulus, while MWNT-CTAB functionalization imparts the highest antioxidant activity and electrical conductivity to the starch matrix. The properties of starch-based films can be tailored based on the physical adsorption of each surfactant on MWNT surface and/or the interfacial interaction of the surfactant with starch chains.