Micellar‐Mediated Block Copolymer Ordering Dynamics Revealed by In Situ Grazing Incidence Small‐Angle X‐Ray Scattering during Spin Coating

Abstract

Spin coating is one of the most versatile methods to generate nanostructured block copolymer (BCP) thin films which are highly desired for many applications such as nanolithography or organic electronics. The self‐assembly pathways through phase separation, both in solvent and in bulk, strongly influence the final BCP structure obtained after spin coating. As a demonstration, the formation of highly ordered in‐plane lamellae is elucidated herein by using in situ grazing incidence small‐angle X‐ray scattering. A key step in this complex fast organization process is the formation of intermediate micellar phases triggered by solvent affinity toward one of the block. Indeed, directional coalescence of a short‐lived intermediate hexagonal structure of cylindrical micelles enables the development of a final highly ordered lamellar structure, predominantly oriented parallel to the substrate surface. These results suggest that the existence of such transient micellar phases is a crucial process in order to produce highly ordered structures with a specific orientation directly after the BCP thin film deposition; and should be the focus of further optimization for the directed self‐assembly and, more generally, in the bottom‐up nanostructure fabrication.

Mechanism of Crystal Formation in Ruddlesden–Popper Sn‐Based Perovskites

“…Next, we investigated the mechanism of formation that brings the RDP hybrid Sn‐based perovskites to adopt the observed layered structure, as well as the mechanism of formation of the pure 3D and pure 2D perovskite thin films during spin coating by in situ GIWAXS. A home built on line spin coater used for previous in situ GISAXS experiments [ 37,38 ] was equipped with a remotely controlled injection system able to sequentially dispense two different solutions under N 2 gas inert atmosphere (Figure S5, Supporting Information). The spin coating experiments have been performed at 2000 rpm, without and with antisolvent injection.…”

Synthesis of High χ–Low N Diblock Copolymers by Polymerization‐Induced Self‐Assembly

“…Similar observations were recently reported for poly(1,1-dimethyl silacyclobutane)-poly(methyl methacrylate) diblock copolymer films cast from nanoparticle dispersions prepared via traditional post-polymerization processing. [22] However, PISA offers decisive advantages over post-polymerization processing for industrial scale-up, since the latter approach invariably involves multiple steps, toxic organic co-solvents and relatively dilute copolymer solutions. Overall, aqueous PISA formulations enable both the efficient synthesis and convenient processing of high clow N diblock copolymers, allowing the facile preparation of thin films with small feature sizes (in this case with L 0 /2 = 8.9 nm).…”

Solvent‐Actuated Self‐Assembly of Amphiphilic Hole‐Transporting Polymer Enables Bottom‐Surface Passivation of Perovskite Film for Efficient Photovoltaics

“…This inference is totally accordant with a recent report, in which ordering dynamics of an amphiphilic block copolymer during spin‐coating has been studied, revealing a micellar‐mediated self‐assembly behavior in such a fast process of solvent evaporation. [ 19 ]…”