Self-Patterning Tetrathiafulvalene Crystalline Films

St John Whittaker, Merritt McDowell, Justin Bendesky, Zhihua An, Yongfan Yang, Hengyu Zhou, Yuze Zhang, Alexander G. Shtukenberg, Dilhan M. Kalyon, Bart Kahr, Stephanie S. Lee

Research output: Contribution to journalArticlepeer-review


Tetrathiafulvalene (TTF) crystals grown from the melt are organized as spherulites in which helicoidal fibrils growing radially from the nucleation center twist in concert with one another. Alternating bright and dark concentric bands are apparent when films are viewed between crossed polarizers, indicating an alternating pattern of crystallographic faces exposed at the film surface. Band-dependent reorganization of the TTF crystals was observed during exposure to methanol vapor. Crystalline growth appears on bright bands at the expense of the dark bands. After a 24 h period of exposure to methanol vapor, the original spherulites were completely restructured, and the films comprise isolated, concentric circles of crystallites whose orientations are determined by the initial TTF crystal fibril orientation. While the surface of these outgrowths appears faceted and smooth, cross-sectional SEM images revealed a semiporous inner structure, suggesting solvent-vapor-induced recrystallization. Collectively, these results show that crystal twisting can be used to rhythmically redistribute material. Crystal twisting is a common and often controllable phenomenon independent of molecular or crystal structure and therefore offers a generalizable path to spontaneous pattern formation in a wide range of materials.

Original languageEnglish (US)
Pages (from-to)8599-8606
Number of pages8
JournalChemistry of Materials
Issue number20
StatePublished - Oct 24 2023

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Materials Chemistry


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