Public Research Seminar by Advanced Materials Thrust, Function Hub, HKUST(GZ) - The structure formation and application of disentangled semi-crystalline polymers
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Crystallization of polymers from entangled melts generally leads to the formation of semicrystalline materials with a nanoscopic morphology consisting of stacks of alternating crystalline and amorphous layers. The factors controlling the thickness of the crystalline layers were extensively studied; however, there is no quantitative understanding of the thickness of the amorphous layers. We elucidate the effect of entanglements on the semicrystalline morphology by the use of a series of model blends of high-molecular weight polymers with unentangled oligomers leading to a reduced entanglement density in the melt as characterized by rheological measurements. Small-angle X-ray scattering experiments after isothermal crystallization reveal a reduced thickness of the amorphous layers, while the crystal thickness remains largely unaffected. We introduce a simple, yet quantitative model without adjustable parameters, according to which the measured thickness of the amorphous layers adjusts itself in such a way that the entanglement concentration reaches a specific maximum value. Furthermore, our model suggests an explanation for the large supercooling that is typically required for crystallization of polymers if entanglements cannot be dissolved during crystallization. At the same time, using the same polymer viscoelasticity and crystallography theory, a phase change material with ultra-high phase change enthalpy and stable structure was prepared.
Zefan Wang received his Ph.D in polymer physics from Institute of Chemistry, Chinese Academy of Science (ICCAS) in 2018 under the supervision of Prof. Dujin Wang and Prof. Xia Dong. After postdoctoral work at the Martin-Luther University with Prof. Thomas Thurn-Albrecht, he joined Shenzhen University in 2022. Currently his research interests mainly focus on the rheological behavior and mechanic properties of semi-crystalline polymers, especially on gel-spinning of UHMWPE fibers through the combination of characterization methods, i. e. SAXS, flash DSC, rheological measurements. Now he is editor for the journal of Polymer Crystallization.
Publications and Patents
- Zefan Wang*, Shuxian Liu, Caizhen Zhu*, Jian Xu. Physical entanglement supported polymeric stable phase change materials with ultra-high melting enthalpy. Advanced Materials, Accepted
- Zefan Wang*, Leire Sangroniz, Jian Xu, Caizhen Zhu*, Alejandro J. Mueller*. Polymer physics behind the gel-spinning of UHMWPE fibers. Macromolecular Rapid Communications, Accepted.
- Zefan Wang*, Mareen Schaller, Albrecht Petzold, Kay Saalwaechter, Thomas Thurn-Albrecht. Origin of Lamellar Stack Structures in Dilute Semicrystalline Polymers: Role of Entanglements and Tie-Molecules. Macromolecules 2024, 57, 4, 1632-1641.
- Zefan Wang, Xia Dong, Alejandro J. Müller, Dario Cavallo, Dujin Wang. Promotion of Self-nucleation with Latent Nuclei in Polybutene-1 and its Copolymer Macromolecules 2018, 51(15), 6037-6046.
- Zefan Wang, Mareen Schaller, Albrecht Petzold, Kay Saalwaechter, Thomas Thurn-Albrecht*. How entanglements determine the morphology of semi-crystalline polymers. Proc. Nat. Acad. Sci. 2023, Vol. 120 No. 27 e2217363120 (Direct Submission)
- Zefan Wang, Wenhong Yang, Guoming Liu, Alejandro J. Müller, Ying Zhao, Xia Dong, Kezhi Wang, Dujin Wang. Probing into the Epitaxial Crystallization of β Form Isotactic Polypropylene: From Experimental Observations to Molecular Mechanics Computation. Journal of Polymer Science Part B: Polymer Physics 2017, 55, 418-424 (Cover).
- Zefan Wang, Yucheng He, Alejandro J. Mueller. Using PCL oligomers to study the differences in melting behavior between polymers and small molecules crystals[J]. Polymer 2023,271, (1):125783.
- Zefan Wang, Xia Dong, Guoming Liu, Qian Xing, Dario Cavallo, Qianhong Jiang, Alejandro J. Müller, Dujin Wang. Interfacial Nucleation in iPP/PB-1 Blends Promotes the Formation of Polybutene-1 Trigonal Crystals, Polymer 2018, 138, 396-406
- Guangyu Shi, Zefan Wang, Ming Wang, Guoming Liu, Dario Cavallo, Alejandro J. Mueller, and Dujin Wang. Crystallization, orientation and solid-solid crystal transition of polybutene-1 confined within nanoporous alumina. Macromolecules 2020, 53, 15, 6510-6518 (equal contribution)
- Zefan Wang, Xia Dong, Dario Cavallo, Alejandro J. Müller, Dujin Wang. Peculiar self-nucleation behavior of a polybutene-1/ethylene random copolymer. Polymer Crystallization Accepted. Doi: 10.1002/pcr2.10201
- Zefan Wang*; Yu Wang; Yunlan Su; Qian Xing*; Alejandro J. Müller. Strain controlled shear hardening behavior in suspensions of alumina spheres in a polydimethylsiloxane oligomer matrix. Polymers for Advanced Technologies 2023, N/A(N/A): 1-9.
- 王泽凡*，姜千红，邢倩*，王笃金。聚丙烯片晶厚度对受限空间内聚丁烯-1三方晶型形成的影响。高分子学报 2023，53，5， 514-521。