Controlling Self‐Assembly in Gyroid Terpolymer Films By Solvent Vapor Annealing

Abstract

The efficacy with which solvent vapor annealing (SVA) can control block copolymer self-assembly has so far been demonstrated primarily for the simplest class of copolymer, the linear diblock copolymer. Adding a third distinct block-thereby creating a triblock terpolymer-not only provides convenient access to complex continuous network morphologies, particularly the gyroid phases, but also opens up a route toward the fabrication of novel nanoscale devices such as optical metamaterials. Such applications, however, require the generation of well-ordered 3D continuous networks, which in turn requires a detailed understanding of the SVA process in terpolymer network morphologies. Here, in situ grazing-incidence small-angle X-ray scattering (GISAXS) is employed to study the self-assembly of a gyroid-forming triblock terpolymer during SVA, revealing the effects of several key SVA parameters on the morphology, lateral order, and, in particular, its preservation in the dried film. The robustness of the terpolymer gyroid morphology is a key requirement for successful SVA, allowing the exploration of annealing parameters which may enable the generation of films with long-range order, e.g., for optical metamaterial applications.

Metasurfaces Atop Metamaterials: Surface Morphology Induces Linear Dichroism in Gyroid Optical Metamaterials

“…Scanning electron microscopy (SEM) and polarized optical microscopy images in Figure confirm the successful fabrication of a gold gyroid optical metamaterial with long‐range order. The SEM image in Figure a reveals an arrangement and symmetry of pores which are consistent with a gyroid morphology oriented with the 〈110〉 direction normal to the substrate . This is also consistent with previous results using the same and similar triblock terpolymers under identical and near‐identical fabrication conditions, which were additionally characterized by (grazing‐incidence) small‐angle X‐ray scattering (SAXS) .…”

“…The SEM image in Figure a reveals an arrangement and symmetry of pores which are consistent with a gyroid morphology oriented with the 〈110〉 direction normal to the substrate . This is also consistent with previous results using the same and similar triblock terpolymers under identical and near‐identical fabrication conditions, which were additionally characterized by (grazing‐incidence) small‐angle X‐ray scattering (SAXS) . Linearly polarized optical microscopy (Figure b) reveals domains randomly oriented in‐plane with lateral sizes of ≈50–200 µm, where the color and intensity contrast arises from the linear dichroism of the gyroid metamaterial …”

Strong Circular Dichroism in Single Gyroid Optical Metamaterials

“…ing [40]. We note that grazing-incidence small-angle X-ray scattering of similar gyroid terpolymer films revealed a slight distortion in the out-of-plane direction, which is related to the film processing [45]. Importantly, the subsequent processing of the gold and silver gyroid manufacture differ.…”

Surface Reconstruction Limited Conductivity in Block‐Copolymer Li Battery Electrolytes

“…At thermodynamic equilibrium, this terpolymer phase separates into the alternating gyroid morphology (space group I 4 1 32) consisting of intertwined PI and PEO network struts separated by a PS matrix. [33] This polymer was chosen because of its 3D continuous PEO network providing isotropic ionic conductivity. The glassy PS matrix gives the material the desired mechanical integrity.…”