Quasi block copolymers noncovalent bonded by stereocomplex crystals

• Published in: Giant (Oxford, England) England), 2023-06, Vol.14, p.100150, Article 100150
• Main Authors: Wu, Jiali, Chen, Yihang, Wang, Hengti, Li, Yongjin
• Format: Article
• Language: English
• Subjects: Nanostructure; Noncovalent compatibilization; Quasi-block copolymer (qBCPs); Stereocomplex crystal junction
• ISSN: 2666-5425; 2666-5425
• DOI: 10.1016/j.giant.2023.100150

Self-assembly of block copolymers (BCPs) yields unparalleled opportunities to integrate exquisite characteristics for preparation of advanced nanotechnology materials. The high-yield manufacturing of BCP is extremely desired, yet rarely exploited. Herein, we displayed that stereocomplex crystals (sc) of poly lactide (PLA) enantiomers, acting as pseudo linkage between adjacent polymer chains, enable formation of quasi-block copolymer (qBCPs) by straightforward melt compounding. Identical content of poly (D-lactide) (PDLA) and poly (L-lactide) (PLLA) were pre-grafted onto the backbones of poly styrene (PS) and poly (methyl methacrylate) (PMMA), respectively. Due to the complementary multiple hydrobonding interactions between PDLA and PLLA grafted moieties, PS-“block”-PMMA connected by cocrystallized sc was induced during the subsequent melt processing of PDLA-g-PS/PLLA-g-PMMA, thus allowing local segregation of PS-“block” and PMMA-“block” with nanometer size. The refined morphology, which was resembled with micro-phase separation of classical BCP, can be facilely tuned by varying the length and ratio of enantiomeric PDLA/PLLA grafts. More interestingly, the PS-“block”-PMMA typed qBCPs demonstrated superiority in compatibilizing immiscible PS/PMMA polymer blends, as compared with the classical compatibilizer (PS-block-PMMA) via reactive blending. Overall, our strategy represents a general method to construct noncovalent linked di-block copolymer via industrially relevant melt processing, which is quite challenging to achieve by existing synthetic technologies. We for the first time demonstrate the role of stereocomplex crystals (sc) of PLA enantiomers as pseudo linkage in constructing quasi-block copolymer (qBCPs) by straightforward melt compounding. In addition, a novel “noncovalent compatibilization methodology” by interfacial qBCPs for immiscible polymer blend is further established. [Display omitted]