Structure and Energetics of Grain Boundaries in Self-Assembled Double-Gyroid Block Copolymer Networks
Year: 2026
Type: article
Abstract: Grain boundaries (GBs) are ubiquitous defects in crystalline materials but remain less explored in block copolymer ordered phases. Here, we develop a self-consistent field theory framework to investigate GB structure and energetics in double-gyroid (DG) diblock copolymer networks. Two energy landscapes are obtained for tilt and twist GBs as functions of GB orientations, revealing multiple local minima. The lowest-energy GB among the sampled GBs is an asymmetric-tilt network-switching GB ([1̄1̄1] ATNS) rather than the experimentally observed (422) twin boundary (TB) among the sampled GBs. Comparative analyses of tilt ([1̄1̄1], [100] ATNS) and twist ((422) TB, [01̄1̄] TNS) GBs reveal that, unlike enthalpy-dominated hard matter, GB stability in DG networks is entropy-driven. Twist-type GBs generate new nodes and disrupt nodal coplanarity, causing chain-packing frustration and entropy penalties. Although the [100] ATNS does not generate new nodes, its disruption of nodal coplanarity still incurs large entropy penalties. Conversely, the [1̄1̄1] ATNS preserves favorable network connectivity and minimizes conformational constraints, making it the energetically preferred GB.
Source: Macromolecules
Authors: Jing Chen, Aiping Zhu, Dan Wei, An-Chang Shi, Kai Jiang
Institutions: Xiangtan University, McMaster University, Wuhan University
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
Funders: Innovative Research Group Project of the National Natural Science Foundation of China, Natural Science Foundation of Hunan Province, Xiangtan University, Hunan Provincial Innovation Foundation for Postgraduate, Science and Technology Program of Hunan Province, Natural Sciences and Engineering Research Council of Canada, National Key Research and Development Program of China
OpenAlex ID: W7162522691