title: Structural ordering of organovermiculite: experiments and modeling.
abstract: The ordering of three different sizes of quaternary ammonium salts (QUATs) has been studied with respect to concentration of guests in the host's interlayer gallery. From the modeling, we could verify that small molecules of n-butylammonium salt build a monolayer structure in the vermiculite gallery without reference to concentration. On the other hand, the larger molecules of dodecyltrimethylammonium and dioctadecyldimethylammonium salts are responsive to the numbers of their molecules in the interlayer space of the host, building mono- or bilayered structures. Supersaturated structure of both QUATs keep an arrangement of alkyl chains nearly perpendicular to silicate layers, while only saturated samples exhibit tilted alkyl chains in the gallery. The ordering changes bring out the calculation of mean crystallite size. Low values of the nonbond energy of supersaturated forms predict that those organovermiculites will readily exfoliate, e.g., in polymer/clay nanocomposite.
authors.affiliation: Nanotechnology Center, VSB-Technical University of Ostrava, 17 Listopadu 15, 708 33 Ostrava-Poruba, Czech Republic. grazyna.simha@vsb.cz
authors.forename: Grazyna
authors.initials: G
authors.lastname: Simha Martynková
authors.forename: Marta
authors.initials: M
authors.lastname: Valásková
authors.forename: Pavla
authors.initials: P
authors.lastname: Capková
authors.forename: Vlastimil
authors.initials: V
authors.lastname: Matejka