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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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Screw dislocation-induced pyramidal crystallization of dendron-like macromolecules featuring asymmetric geometry
Xinyu Sun1, Xueyan Feng1, Xiao-Yun Yan1,2
1School of Polymer Science and Polymer Engineering, The University of Akron Akron Ohio 44325 USA tliu@uakron.edu scheng@uakron.edu.
Chemical Science
|October 20, 2021
Summary
Dendron-shaped macromolecules crystallize into pyramid structures, not spheres, using mixed solvents. Molecular asymmetry and solvent choice control the formation of 2D nanosheets and 3D pyramidal crystals.
Area of Science:
- Macromolecular science
- Crystallization science
- Materials science
Background:
- Dendron-shaped macromolecules typically form spherical structures in bulk.
- Controlling macromolecular crystallization is crucial for advanced materials.
Purpose of the Study:
- To investigate the crystallization behavior of dendron-shaped macromolecules in mixed solvents.
- To explore strategies for manipulating macromolecular self-assembly into ordered structures.
Main Methods:
- Utilizing mixed solvents to influence crystallization.
- Designing asymmetric molecular architectures.
- Controlling solvent ratios and compositions during evaporation.
Main Results:
- Dendron-shaped macromolecules AB crystallize into ordered, pyramid-like structures in mixed solvents, deviating from bulk spherical motifs.
- Formation of flat nanosheets is observed, driven by solvent selection and crystalline clusters.
- Defects in 2D nanosheets lead to spiral growth via screw dislocation during solvent evaporation.
- Nanosheet size and transition to 3D pyramidal structures are tunable via solvent parameters.
- Higher macromolecular asymmetry results in less ordered polycrystals due to localized stress.
Conclusions:
- Mixed solvents and asymmetric macromolecular design are effective strategies for controlling crystallization into non-spherical, ordered architectures.
- The study demonstrates a method for fabricating 2D nanosheets and 3D pyramidal structures from dendron-shaped macromolecules.
- Understanding the role of solvent composition and molecular asymmetry is key to directing self-assembly processes.
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