Biopolymer-Targeted Adsorption onto Halloysite Nanotubes in Aqueous Media

Studies on the adsorption of biopolymers onto balloysite nanotubes (HNTs) in water were conducted. Three polymers with different charges anionic (pectin), neutral (hydroxypropyl cellulose), and cationic (chitosan) were chosen. The thermodynamic parameters for the adsorption of polymers onto the HNT surface were determined by isothermal titration calorimetry (ITC). The experimental data were interpreted based on a Langmuir adsorption model. The standard variations in free energy, enthalpy, and entropy of the process were obtained and discussed. Turbitlimory was used to evaluate the stability of functionalized nanoparticles in water. The (zeta-potential clarified the:surface charge properties of functionalized nanotlibes upon polymer adsorption. The interaction of modified nanotubes with polymers led to the formation of a colloidal system with tunable stability and surface properties, which offers different perspectives,on new applications of these dispersions, such as carriers for substances to be released in response to external stimuli.