Jun Taesuk, Park Hyunjun, Jeon Seungbae, Jo Seungyun, Ahn Hyungju, Jang Woo-Dong, Lee Byeongdu, Ryu Du Yeol
Department of Chemical and Biomolecular Engineering, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.
Department of Chemistry, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 03722, Korea.
J Am Chem Soc. 2021 Oct 27;143(42):17548-17556. doi: 10.1021/jacs.1c07313. Epub 2021 Oct 15.
Single-component polymeric materials open up a great potential for self-assembly into mesoscale complex crystal structures that are known as Frank-Kasper (FK) phases. Predicting the packing structures of the soft-matter spheres, however, remains a challenge even when the molecular design is precisely known. Here, we investigate the role of the molecules' enthalpic interaction in determining the low-symmetry crystal structures. To this end, we synthesize architecturally asymmetric dendrons by varying their apex functionalities and examine the packing structures of the second-generation (G2) dendritic wedges. Our work shows that weakening the hydrogen bonding of the dendron apex makes the particles softer and smaller, and leads to the formation of various FK structures at lower temperatures, including the new observation of a FK C14 phase in the cone-shaped dendron systems. As a consequence of the free energy balance between the particle's interfacial tension and the chain's stretching, various packing structures are mainly tuned by designing the hydrogen bonding interaction.
单组分聚合物材料为自组装成中尺度复杂晶体结构开辟了巨大潜力，这些结构被称为弗兰克 - 卡斯帕（FK）相。然而，即便分子设计已精确知晓，预测软物质球体的堆积结构仍是一项挑战。在此，我们研究分子的焓相互作用在确定低对称晶体结构中的作用。为此，我们通过改变其顶端官能团合成了结构不对称的树枝状分子，并研究了第二代（G2）树枝状楔体的堆积结构。我们的工作表明，削弱树枝状分子顶端的氢键会使颗粒更软、更小，并导致在较低温度下形成各种FK结构，包括在锥形树枝状分子体系中首次观察到的FK C14相。由于颗粒界面张力与链拉伸之间的自由能平衡，各种堆积结构主要通过设计氢键相互作用来调节。
