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Updated: Jan 29, 2026
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Synthesis of Monodisperse Cylindrical Nanoparticles via Crystallization-driven Self-assembly of Biodegradable Block Copolymers
Published on: June 20, 2019
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Generalizing the effects of chirality on block copolymer assembly
Hsiao-Fang Wang1, Kai-Chieh Yang1, Wen-Chun Hsu1
1Department of Chemical Engineering, National Tsing Hua University, Hsinchu 30013, Taiwan.
Summary
Chiral block copolymers self-assemble into helical structures, demonstrating chirality transfer from monomers to macroscopic morphology. This study highlights the influence of segment chirality on self-assembly in poly(cyclohexylglycolide)-based materials.
Area of Science:
- Polymer Science
- Materials Chemistry
- Supramolecular Chemistry
Background:
- Chirality in polymers can influence self-assembled structures.
- Previous studies showed chirality transfer in polylactide (PLA)-based block copolymers.
- Understanding chirality's role in self-assembly is crucial for designing advanced materials.
Purpose of the Study:
- To investigate the generality of segment chirality's influence on self-assembled structures in achiral-chiral diblock copolymers.
- To compare poly(cyclohexylglycolide) (PCG)-based chiral block copolymers with previously studied PLA-based systems.
- To determine if chirality at the monomeric level translates to macroscopic helical morphologies.
Main Methods:
- Synthesis of poly(benzyl methacrylate)-b-poly(d-cyclohexylglycolide) (PBnMA-PDCG) and PBnMA-b-poly(l-cyclohexyl glycolide) (PBnMA-PLCG).
- Vibrational circular dichroism (VCD) studies to identify helical chains and interchain interactions.
- 3D transmission electron microscope tomography (3D TEM) to visualize microphase-separated morphologies.
Main Results:
- VCD confirmed opposite-handed helical chains in enantiomeric PCG-based block copolymers, indicating chirality transfer from monomers to intrachain conformation.
- VCD provided evidence for chiral interchain interactions in the melt state.
- 3D TEM revealed a helical phase (H*) with hexagonally ordered, helical tubular domains, whose handedness matched the monomer chirality.
Conclusions:
- Chirality at the monomer and intrachain level dictates the macroscopic, helical symmetry of microphase-separated morphologies.
- Unlike PLA-based systems, the H* phase in PBnMA-PCG is an equilibrium phase due to the lack of competing crystalline states.
- Stronger chiral intersegment forces, arising from bulkier chiral side groups, enhance the thermodynamic stability of the H* morphology.
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