Triple and Two-Way Reversible Shape Memory Polymer Networks with Body Temperature and Water Responsiveness

Abstract

Shape memory polymers (SMPs), as a class of intelligent materials, have shown great potential in biomedical and robotic fields. Although efforts have been made to design and fabricate SMPs in the past decades, most of the SMPs are not suitable for use in the human body due to their unpleasant triggering conditions. Furthermore, it is of great importance to diversify the shape memory effect (SME) of SMPs to extend their applications. In this work, through thiol-ene chemistry, SMPs based on random cross-linked hydrophobic polytetrahydrofuran (PTHF) and hydrophilic poly­(ethylene glycol) (PEG) oligomers were facilely fabricated. These SMPs showed a body temperature-triggered two-way SME with a reversible strain of up to 25.2%. Besides, the SMPs exhibited a good body temperature- and water-triggered one-way triple-SME. These features bestowed the polymers with a bright future in biomedical applications. Polymer P60-G40 was applied as a new type of esophageal stent, and the in vitro assessment showed that the stent was adjustable, self-expandable, and had the ability to release drugs, which were attributed to the one-way triple-SME and two-way SME.

Solvent Responsive Shape Memory Polymers‐ Evolution, Current Status, and Future Outlook

“…The current research already proves that it is possible to develop SMPs that can recover completely to their original shape (one-way SMP) when excited with solvent molecules. [125] However, an interesting question is whether we can develop two-way reversible SMPs responsive to solvents? The possibility of solvents reversibly dilating and contracting a polymer matrix unfolds the possibility of fabricating SMPs that can be fully autonomous and actuate between two predicted shapes.…”

“…Moreover, with the emergence of 3D printing in developing SMPs (popularly termed as 4D printing), [125] we should anticipate polymers processed via additive manufacturing capable of forming complex 3D shapes that are responsive towards solvents. This shall enable the polymers to be used for advanced engineering and biomedical applications that require intricate design and a complex shape morphing process.…”

Hybrid covalent adaptable networks from cross-reactive poly(ε-caprolactone) and poly(ethylene oxide) stars towards advanced shape-memory materials

“…Mechanical properties in the hydrated state especially of the 51 : 49 sample are compatible for its use as self-deploying oesophageal stent for example. 32 The efficient reconfiguration of flat sheets in more complex shapes by remolding opens the door to on-site shaping of medical device to precisely fit the patient needs answering the rapidly developing personalized medicine requirements.…”

“…The Young modulus also remains higher as compared to SM networks based on PEO and PTHF developed for medical device. 32 Watersensitive shape-memory can thus be foreseen for networks of both compositions.…”

Shape-Memory Polymers Hallmarks and Their Biomedical Applications in the Form of Nanofibers

“…Liang et al, developed a two-way shape-memory polymer network which was reversible with body temperature and was water responsive [54]. SMP (P60-G40), obtained by random crosslinking of hydrophobic poly(tetrahydrofuran) and hydrophilic poly(ethylene glycol) (PEG) oligomers, was applied as a new type of esophageal stent, and the in vitro assessment showed that the stent was adjustable, self-expandable, and had the ability to load and release drugs.…”