Phase-transition-induced jumping, bending, and wriggling of single crystal nanofibers of coronene

Abstract

For decades, it has been reported that some organic crystals suddenly crack, break, or jump when they are heated from room temperature. Recently, such crystals have been intensively studied both in fundamental science and for high-speed mechanical device applications. According to these studies, the sudden crystal motions have been attributed to structural phase transitions induced by heating. Stress created by the phase transition is released through the sudden and rapid motion of the crystals. Here we report that single crystal nanofibers of coronene exhibit a new type of ultrafast motion when they are cooled from room temperature and subsequently heated to room temperature. The nanofibers make centimeter-scale jumps accompanied by surprisingly unique behaviors such as sharp bending and wriggling. We found that the motions are caused by a significantly fast structural phase transition between two polymorphs of coronene. A theoretical investigation revealed that the sudden force generated by the phase transition together with the nanoscale dimensions and elastic properties create dynamical instability in the nanofibers that results in the motions. Our finding demonstrates the novel mechanism that leads to ultrafast, large deformation of organic crystals.

Multifunctional Deformable Organic Semiconductor Single Crystals

“…[14,15] Device components that are based on organic (semi)conductors can be implemented in flexible waveguides,f ield-effect transistors,t elecommunication devices,a nd solar cells.T he light weight, determined by their chemical composition, as well as the mechanical robustness and compliance,r ooted in their non-covalent interactions,s tand among the most important aspects of the performance of organic crystals.A long this line of pursuit, their mechanical attributes,which are critically important for durability and robustness of the ensuing devices,a re becoming apopular subject of exploration within the emerging field of crystal adaptronics. [16][17][18][19][20][21][22][23][24][25][26][27][28][29][30] Thep rospects of using dynamic crystals have already been demonstrated with lab-scale applications that include prototypical fuses, [31] transistors, [32] and switches. [33] Of particular interest are the effects of mechanically induced structural transitions in semiconducting single-crystal electrical devices.…”

Repeatable Actuations of Organic Single Crystal Fibers Driven by Thermosalient‐Phase‐Transition‐Induced Buckling

“…We had previously reported a facile method to control the evaporation speed of a solution that was deposited on a glass substrate and that slow solvent evaporation resulted in the self-assembly of high-quality Small 2022, 18, 2204500 single-crystalline nano/microfibers of coronene and cyanine dye on the substrate. [3,6] We applied this method to TBB and succeeded in preparing nano/microfibers of TBB on a glass substrate (see the Experimental Section). Figure 2a shows an optical micrograph of a sample prepared using an ethanol solution of TBB.…”

“…This value is close to that estimated for the compressive force generated along the long axis of coronene nanofibers at the phase transition (1.2 × 10 −1 MPa). [ 3 ] This may suggest that values of this order are typical for thermosalient crystals of π‐stacked molecules. When the temperature was lowered from T = 40 °C, the fiber rapidly transformed into a straight shape at T ≈ 35 °C, indicating that it transformed back to the β‐polymorph (Movie S4, Supporting Information).…”

Fabrication and Optical Properties of Fiber-Shaped Pseudoisocyanine J-Aggregates Grown Directly on a Glass Substrate

“…Four droplets of the solution (∼5 × 10 –2 mL) were deposited on each cover slip, and a lid was immediately placed over the dish. This led to slow evaporation of the solvent at nearly saturated vapor pressure. , After the solvent was evaporated in ∼2 h, the samples were extracted from the dish and dried under ambient conditions. In this article, the samples prepared using Solutions 1–4 via slow evaporation of the solvent are referred to as Samples 1–4, respectively.…”