Self-assembly of block copolymers under non-isothermal annealing conditions as revealed by grazing-incidence small-angle X-ray scattering

Abstract

An accurate knowledge of the parameters governing the kinetics of block copolymer self-assembly is crucial to model the time- and temperature-dependent evolution of pattern formation during annealing as well as to predict the most efficient conditions for the formation of defect-free patterns. Here, the self-assembly kinetics of a lamellar PS-b-PMMA block copolymer under both isothermal and non-isothermal annealing conditions are investigated by combining grazing-incidence small-angle X-ray scattering (GISAXS) experiments with a novel modelling methodology that accounts for the annealing history of the block copolymer film before it reaches the isothermal regime. Such a model allows conventional studies in isothermal annealing conditions to be extended to the more realistic case of non-isothermal annealing and prediction of the accuracy in the determination of the relevant parameters, namely the correlation length and the growth exponent, which define the kinetics of the self-assembly.

Hybrid Metrology for Nanostructured Optical Metasurfaces

“…The lamellar nanostructures’ lateral periodicity L 0 can be extracted by assessing the distance of the first-order diffraction maximum to the zero-diffraction order following the expression: where m is the order of the reflection, in which m = 1 for the first scattering peak, and q y is the scattering peak position of the first diffraction order. In the case of cylindrical nanostructures the two-dimensional hexagonal lattice is expressed as For both morphologies, the first-order intensity peak was found by tracing cuts along the q y at a constant q z as illustrated in Figure m.…”

“…Further analysis of the q 10 intensity peak can be applied to extract information about the long-range lateral ordering of the nanostructures. To this end, the Scherrer formula, relates the full width at half-maximum of the first Bragg order peak to the average grain size of self-assembled patterns, providing direct information on ξ . As reported in Table , all samples, whether lamellar or cylindrical morphologies, exhibit high ξ values exceeding 400 nm.…”

“…To this end, the Scherrer formula, 52 relates the full width at half-maximum of the first Bragg order peak to the average grain size of self-assembled patterns, providing direct information on ξ. 47 As reported in Table 1, all samples, whether lamellar or cylindrical morphologies, exhibit high ξ values exceeding 400 nm. However, two distinct variations on the ξ can be observed for lamellar (LAM146 and LAM160) and cylindrical (CYL82 and CYL102) nanostructures.…”

Study of the Crystal Structure and Hydrogen Bonding during Cold Crystallization of Poly(trimethylene 2,5-furandicarboxylate)

“…In order to monitor by X-ray scattering the crystallization process in similar samples to those used for FTIR experiments (PTF on IR transparent silicon substrates), we used GIWAXS as described elsewhere. 29 GIWAXS measurements were performed in the NCD-SWEET beamline at the ALBA synchrotron (Cerdanyola del Vallès, Barcelona, Spain). The X-ray beam wavelength was set at λ = 0.1 nm.…”

Solvent-assisted self-assembly of block copolymer thin films

“…For analysis of grain-coarsening during slow heating ramps Fernandez-Regulez et al proposed an approach, in which the non-isothermal annealing is divided into short quasi-isothermal intervals. 284 For each growth interval the preexisting grain size ξ 0 , ξ 0 = A ( T ) t α eq is related to the equivalent annealing time, t eq , used to translate the current growth curve to a next thermal interval step ( ξ = A ( T )( t + t eq ) α ). The computation is iterated until final temperature is reached.…”