Guest-Induced Large and Tunable Negative Thermal Expansion in Soft Microporous Carbon.
basic_science · Level V
Where this comes from
- Record sourced from PubMed, PMID 41579404.
- Also identified by DOI 10.1021/acsnano.5c17601 and PMC identifier 12895563.
- Licence recorded as CC BY-NC-ND.
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Abstract
Materials that exhibit negative thermal expansion (NTE) are of fundamental interest due to their rarity and counterintuitive behavior. While research in this area has been directed toward the discovery of materials that display NTE and explaining its origin, there has been less attention to describing the complexities of a secondary phase or other guests that could influence the magnitude and mechanism of NTE. We report herein that zeolite-templated carbon (ZTC), a soft carbonaceous framework solid with ordered microporosity, exhibits a large and widely tunable thermal expansion in the presence of adsorbed guests. For ZTC in the presence of CO<sub>2</sub> at 1 bar, the largest coefficient of isotropic NTE ever observed (-8.4 × 10<sup>-4</sup> K<sup>-1</sup>) is measured between 200 and 220 K. These results comprise a tunable mechanism of thermal expansion based on the interaction between two independent, positively expanding phases that together give rise to an anomalous guest-induced NTE under certain conditions.