title: Steric stabilization of modified nanoclays triggered by temperature.
abstract: Halloysite clay nanotubes were modified through the adsorption of poly(N-isopropylacrylamide)-amine terminated (PNIPA-NH2) onto the external surface by exploiting electrostatic interactions at pH=6. In spite the amount of attached polymer is rather low (1 wt%), the properties of the nanotubes are deeply modified. The apparent specific volume and isentropic compressibilities of the hybrid nanomaterial dispersed in water evidenced the transferring of the termosensitive property from the polymer to halloysite. The hydrodynamic radius as well as the ζ-potential of the nanohybrid are consistent with the attachment of a positively charged polymer onto the negative surface of the nanotube. The colloidal stability was strongly enhanced in the temperature domain below the lower critical solution temperature. This methodology endowed to obtain hollow nanotubes with a stimuli-responsive corona.
authors.affiliation: Department of Physics and Chemistry, Università degli Studi di Palermo, Viale delle Scienze, pad. 17, 90128 Palermo, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Cavallaro
authors.affiliation: Department of Physics and Chemistry, Università degli Studi di Palermo, Viale delle Scienze, pad. 17, 90128 Palermo, Italy. Electronic address: giuseppe.lazzara@unipa.it.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Lazzara
authors.affiliation: Department of Physics and Chemistry, Università degli Studi di Palermo, Viale delle Scienze, pad. 17, 90128 Palermo, Italy.
authors.forename: Stefana
authors.initials: S
authors.lastname: Milioto
authors.affiliation: Department of Physics and Chemistry, Università degli Studi di Palermo, Viale delle Scienze, pad. 17, 90128 Palermo, Italy.
authors.forename: Filippo
authors.initials: F
authors.lastname: Parisi
keywords: Halloysite; Hydrodynamic radius; Nanoclay; PNIPA-NH(2); ζ-potential