title: Self-immobilization and/or thermal treatment for preparing silica-poly(methyloctylsiloxane) stationary phases.
abstract: Batches of poly(methyloctylsiloxane) (PMOS)-loaded silica were prepared by the deposition of PMOS, into the pores of HPLC silica. Portions of PMOS-loaded silica were allowed to remain at ambient temperature, without further treatment for 2, 9, 20, 31, 51, 105 and 184 days after preparation to undergo self-immobilization (irreversible adsorption of a layer of polymer on silica at ambient temperature in the absence of initiators). Other portions were subjected to a thermal treatment (100 degrees C for 4h) after 1, 2, 5, 7, 9, 15, 20, 25, 70, 111 and 184 days. Self-immobilized and thermally treated samples were characterized by % C, 29Si cross-polarization magic angle spinning (CP/MAS) NMR spectroscopy and reversed-phase column performance. The results show that thermal immobilization accelerates the distribution and rearrangement of the polymer on the silica surface. However, from the time that a monolayer has been formed by self-immobilization (approximately 100 days for PMOS on Kromasil silica), the thermal treatment does not alter this configuration and, thus, does not change the resulting chromatographic parameters.
authors.affiliation: LABCROM-Laboratório de Pesquisas em Cromatografia Líquida, Instituto de Química, Universidade Estadual de Campinas, Caixa Postal 6154, 13084-971 Campinas SP, Brazil.
authors.forename: Carla B G
authors.initials: CB
authors.lastname: Bottoli
authors.forename: Camila R M
authors.initials: CR
authors.lastname: Vigna
authors.forename: Gerd
authors.initials: G
authors.lastname: Fischer
authors.forename: Klaus
authors.initials: K
authors.lastname: Albert
authors.forename: Kenneth E
authors.initials: KE
authors.lastname: Collins
authors.forename: Carol H
authors.initials: CH
authors.lastname: Collins
mesh_terms: D009682:Magnetic Resonance Spectroscopy; D011108:Polymers / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D012833:Siloxanes / Q000737:chemistry*
chemical_list: D011108:Polymers; D012833:Siloxanes; C475630:poly(methyloctylsiloxane); D012822:Silicon Dioxide