Visualizing the double-gyroid twin

Abstract

Periodic gyroid network materials have many interesting properties (band gaps, topologically protected modes, superior charge and mass transport, and outstanding mechanical properties) due to the space-group symmetries and their multichannel triply continuous morphology. The three-dimensional structure of a twin boundary in a self-assembled polystyrene-b-polydimethylsiloxane (PS-PDMS) double-gyroid (DG) forming diblock copolymer is directly visualized using dual-beam scanning microscopy. The reconstruction clearly shows that the intermaterial dividing surface (IMDS) is smooth and continuous across the boundary plane as the pairs of chiral PDMS networks suddenly change their handedness. The boundary plane therefore acts as a topological mirror. The morphology of the normally chiral nodes and strut loops within the networks is altered in the twin-boundary plane with the formation of three new types of achiral nodes and the appearance of two new classes of achiral loops. The boundary region shares a very similar surface/volume ratio and distribution of the mean and Gaussian curvatures of the IMDS as the adjacent ordered DG grain regions, suggesting the twin is a low-energy boundary.

Bicontinuous Gyroid Phase of a Water-Swollen Wedge-Shaped Amphiphile: Studies with In-Situ Grazing-Incidence X-ray Scattering and Atomic Force Microscopy

“…An example of such measurement is given in Figure 6 , where AFM phase images of C8Pyr thin films at different RH values are shown. Despite some noise present in the images (the images after filtering are shown in the insets), one can recognize the unique pattern of the 211 plane of the double gyroid phase (see, e.g., Reference [ 39 ]). The observed morphological features of the 211 plane can be viewed relative to the and reciprocal space vectors that direct along and perpendicular to the characteristic “knitting” features of the plane, respectively.…”

“…Taking into account the expressions for both distances given in ref. [ 39 ], one obtains the lattice parameter of the gyroid phase to be 12.4 and 12.8 nm, respectively. These values agree relatively well with the corresponding SAXS unit cell parameter, which validates such AFM-based analysis.…”

Applications of Hybrid Polymers Generated from Living Anionic Ring Opening Polymerization

“…This work led to the observation of periodic double gyroid (DG) behavior, as well as a series of publications displaying an appreciation of the potential for extended novel 3D structures ( Figure 14 ) [ 180 , 181 , 182 ]. As suggested by the DG topological visualizations of Thomas [ 183 ], potential structural, dielectric, charge transport, and mass transport material behavior can be controlled by the direct use of DG block polymers structures or by the removal, conversion, and/or infiltration of a DG microphase.…”

“… Reconstruction of a volume containing a Double Gyroid of PS-b-PDMS (Reprinted with permission from Ref. [ 183 ] Copyright 2021 National Academy of Sciences). …”

Tilt grain boundaries of hexagonal structures: a spectral viewpoint

“…Grain boundaries (GBs) are transition regions between two grains of the same ordered phase with different orientations. Many experimental and theoretical studies have been performed on the GBs of various systems, including metals [3,2,26] and soft matters [17,7]. GBs heavily affect material properties, such as strength, plasticity [21], toughness [27], and corrosion resistance [24].…”