title: GISAXS Analysis of the In-Depth Morphology of Thick PS-b-PMMA Films.
abstract: The morphological evolution of cylinder-forming poly(styrene)-b-poly(methyl methacrylate) block copolymer (BCP) thick films treated at high temperatures in the rapid thermal processing (RTP) machine was monitored by means of in-depth grazing-incidence small-angle X-ray scattering (GISAXS). The use of this nondisruptive technique allowed one to reveal the formation of buried layers composed of both parallel- and perpendicular-oriented cylinders as a function of the film thickness (24 ≤ h ≤ 840 nm) and annealing time (0 ≤ t ≤ 900 s). Three distinct behaviors were observed depending on the film thickness. Up to h ≤ 160 nm, a homogeneous film consisting of perpendicular-oriented cylinders is observed. When h is between 160 and 700 nm, a decoupling process between both the air-BCP and substrate-BCP interfaces takes place, leading to the formation of mixed orientations (parallel and perpendicular) of the cylinders. Finally, for h > 700 nm, the two interfaces are completely decoupled, and the formation of a superficial layer of about 50 nm composed of perpendicular cylinders is observed. Furthermore, the through-film morphology affects the nanodomain long-range order, which substantially decreases in correspondence with the beginning of the decoupling process. When the thick samples are exposed to longer thermal treatments, an increase in the long-range order of the nanodomains occurs, without any sensible variation of the thickness of the superficial layer.
authors.affiliation: Laboratorio MDM, IMM-CNR , Via C. Olivetti 2, 20864 Agrate Brianza, Italy.|Nanoscience and Materials Division, Istituto Nazionale Ricerca Metrologica , Strada delle Cacce 91, 10135 Torino, Italy.
authors.forename: Federico
authors.identifier: http://orcid.org/0000-0002-1055-8839
authors.initials: F
authors.lastname: Ferrarese Lupi
authors.affiliation: Laboratorio MDM, IMM-CNR , Via C. Olivetti 2, 20864 Agrate Brianza, Italy.|Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale ''A. Avogadro'' , Viale T. Michel 11, 1512 Alessandria, Italy.
authors.forename: Tommaso Jacopo
authors.initials: TJ
authors.lastname: Giammaria
authors.affiliation: Laboratorio MDM, IMM-CNR , Via C. Olivetti 2, 20864 Agrate Brianza, Italy.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Seguini
authors.affiliation: Dipartimento di Scienze e Innovazione Tecnologica, Università del Piemonte Orientale ''A. Avogadro'' , Viale T. Michel 11, 1512 Alessandria, Italy.
authors.forename: Michele
authors.initials: M
authors.lastname: Laus
authors.affiliation: Institut Ruđer Bošković , Bijenička cesta 54, 10000 Zagreb, Croatia.
authors.forename: Pavo
authors.initials: P
authors.lastname: Dubček
authors.affiliation: Institut Ruđer Bošković , Bijenička cesta 54, 10000 Zagreb, Croatia.
authors.forename: Branko
authors.initials: B
authors.lastname: Pivac
authors.affiliation: Elettra-Sincrotrone Trieste , SS 14, Km 163.5, in AREA Science Park, 34149 Basovizza (TS), Italy.
authors.forename: Sigrid
authors.identifier: http://orcid.org/0000-0001-6451-5159
authors.initials: S
authors.lastname: Bernstorff
authors.affiliation: Laboratorio MDM, IMM-CNR , Via C. Olivetti 2, 20864 Agrate Brianza, Italy.
authors.forename: Michele
authors.identifier: http://orcid.org/0000-0001-7431-1969
authors.initials: M
authors.lastname: Perego
keywords: GISAXS; PS-b-PMMA; block copolymers; rapid thermal processing; self-assembly