Fabrication of Microfibers with Complex Interior by Shape-Changing Polymers
Final Report Abstract
In summary, our project involved understanding the fundamental principles of fabricating layers with embedded stress. We applied this knowledge to fabricate sheets that undergo programmed shape transformation, enabling the fabrication of fibers with complex interiors. We synthesized polymers with different chemical structures and molecular weights and studied the impact of their structure on rheological properties. This understanding was crucial for depositing polymers in a stressed state and programming shape transformation. We explored the use of two deposition techniques: melt electrowriting and electrospinning. Through experimentation, we discovered that melt electrowriting, under its standard working conditions, allows for the deposition of polymers in a stress-free state. However, by pushing melt electrowriting to its limits, we were able to program stress in the deposited polymers, which could be utilized for programmed shape transformation. On the other hand, electrospinning proved to be superior to melt electrowriting in terms of depositing polymers in a stressed state. To stabilize the stressed state, we employed reinforced crystallization at low temperatures. We demonstrated that combining stressed-by-fabrication electrospun polymers with stress-free melt-electrowritten polymers in a bilayer structure enabled programmed shape transformation. Furthermore, by utilizing shape-memory polymers with a crystallizing soft block, we achieved bidirectional shape transformation. This means that the scrolled structure could tighten and untighten cyclically as the temperature changed.
Publications
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Shape-morphing architectures actuated by Janus fibers. Soft Matter, 16(8), 2086-2092.
Zakharov, Andrei; Pismen, Len M. & Ionov, Leonid
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Two-Way Shape Memory Polymers: Evolution of Stress vs Evolution of Elongation. Macromolecules, 54(12), 5838-5847.
Murcia, Andrés Posada; Gomez, Juan Manuel Uribe; Sommer, Jens-Uwe & Ionov, Leonid
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A thermo-, near-infrared light- and water-induced shape memory polymer with healing fatigued shape memory performance. Materials Chemistry Frontiers, 6(9), 1218-1227.
Bai, Yongkang & Ionov, Leonid
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Mechanism of Behavior of Two-Way Shape Memory Polymer under Constant Strain Conditions. Macromolecules, 55(5), 1680-1689.
Posada-Murcia, Andrés; Uribe-Gomez, Juan Manuel; Förster, Stephan; Sommer, Jens-Uwe; Dulle, Martin & Ionov, Leonid
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Smart Mechanically Tunable Surfaces with Shape Memory Behavior and Wetting-Programmable Topography. ACS Applied Materials & Interfaces, 14(17), 20208-20219.
Constante, Gissela; Apsite, Indra; Auerbach, Paul; Aland, Sebastian; Schönfeld, Dennis; Pretsch, Thorsten; Milkin, Pavel & Ionov, Leonid
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Reversibly Photoswitchable High‐Aspect Ratio Surfaces. Small Structures, 4(10).
Constante, Gissela; Apsite, Indra; Schönfeld, Dennis; Pretsch, Thorsten & Ionov, Leonid
