Self-Assembly of Chiral Menthol Molecules from a Liquid Film into Ring-Banded Spherulites

Tamás Kovács,Gábor Holló,Zita Zuba,János Molnár,Rózsa Szűcs,István Lagzi,Hugo K Christenson

doi:10.1021/acs.cgd.9b00465

Abstract

We investigate the growth of spherulites in the wake of a solidification front in a thin film of liquid menthol. We observed that the two enantiomeric forms of menthol ((−)-menthol and (+)-menthol)...

Highlights

Phase transitions are general phenomena in nature and in the laboratory that have a significant effect on natural processes and on applications in industrial processes.[1]
Sometimes, when the pattern formation started from several centers, the evolving fronts merged together, forming empty linear edges (Voronoi patterns), which were observed in some other chemical systems (Figure 2).[45,46]
We found that the enantiomeric pure menthol produces ring-banded spherulites, whereas their racemic mixture forms only nonbanded spherulites

Summary

■ INTRODUCTION

Phase transitions (including crystallization and solidification) are general phenomena in nature and in the laboratory that have a significant effect on natural processes and on applications in industrial processes (e.g., zone melting, polymer formation).[1]. Garner and Randall concluded that the rhythmic solidification occurs due to the temperature differences of crystallization at liquid−air and liquid−glass interfaces.[16] MacMasters and coworkers suggested a simple model for the rhythmic crystallization of different dichromate substances that showed similar Liesegang ring phenomena.[17] Shtukenberg et al investigated the helical fibril formation of D-mannitol as a function of additive content and temperature and concluded that periodic oscillation of circular birefringence occurs due to the periodic variation of the misorientation of the overlapping lamellae.[18] Benbow and Wood suggested that is a high degree of supercooling required for rhythmic solidification to occur and a large variation in surface tension with temperature is essential.[19] They suggest that the emitted latent heat is passed rapidly onto the surrounding supercooled melt if solidification is started from a highly supercooled liquid. To initiate the phase transition and a solidification front, a perturbation must be applied

■ RESULTS AND DISCUSSION

■ CONCLUSIONS

■ ACKNOWLEDGMENTS

■ REFERENCES