State and Local Joint Engineering Laboratory for Novel Functional Polymeric Materials, College of Chemistry, Chemical Engineering and Materials Science, Soochow University, Suzhou 215123, China.
Jiangsu Key Laboratory of Micro and Nano Heat Fluid Flow Technology and Energy Application, School of Physical Science and Technology, Suzhou University of Science and Technology, Suzhou 215009, China.
ACS Macro Lett. 2023 Mar 21;12(3):369-375. doi: 10.1021/acsmacrolett.2c00753. Epub 2023 Feb 27.
We demonstrate herein a bottom-up strategy for achieving helical crystals via chiral amplification in copolyesters by incorporating a small amount of (d)-isosorbide into semicrystalline polyester, poly(ethylene brassylate) (PEB). During bulk crystallization of poly(ethylene--isosorbide brassylate)s, the molecular chirality of isosorbide in the amorphous region is transferred to PEB crystal chirality and amplified by the formation of right-handed helical crystals. Increasing isosorbide content or reducing crystallization temperature leads to thinner PEB lamellae crystals, strengthening chiral amplification by forming superhelices with a smaller helical pitch. Moreover, the superhelices with smaller helical pitch (larger chiral amplification) endow aliphatic copolyesters with enhanced modulus, strength, and toughness without sacrificing elongation-at-break. The principle outlined here could apply to the design of strong and tough materials.
我们在此展示了一种自下而上的策略，通过在半结晶聚酯聚（对苯二甲酸乙二醇酯）（PEB）中加入少量（d）-异山梨醇，在共聚酯中通过手性放大来实现螺旋晶体。在聚（对苯二甲酸乙二醇酯-异山梨醇酯）的本体结晶过程中，异山梨醇在非晶区的分子手性被转移到 PEB 晶体手性，并通过形成右手螺旋晶体得到放大。增加异山梨醇的含量或降低结晶温度会导致 PEB 更薄的层状晶体形成，通过形成具有较小螺旋间距的超螺旋来增强手性放大。此外，具有较小螺旋间距（更大的手性放大）的超螺旋赋予脂肪族共聚酯更高的模量、强度和韧性，而不会牺牲断裂伸长率。这里概述的原理可适用于设计高强度和高韧性的材料。
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