Chemo-responsive shape memory effect in shape memory polyurethane triggered by inductive release of mechanical energy storage undergoing copper (II) chloride migration

Abstract

In this study, 10% weight fraction of copper (II) chloride (CuCl2) was embedded into shape memory polyurethane (SMPU) by dissolving it in a solvent mixture of tetrahydrofuran and N,N-dimethyl formamide. It is found that CuCl2 particles migrate; they are released from the polymer in the water-driven shape recovery process of SMPU composites. SMPU composites, after various immersion times in water, were characterized by Fourier transform infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis. Experimental results support that hydrogen bonding between polyurethane macromolecules and water molecules is the driving force, resulting from the inductive decrease in the glass transition temperature. Furthermore, the release of the stored mechanical energy in SMPU is demonstrated by means of tracking the migration of CuCl2 particles via x-ray diffraction and scanning electron microscopy tests. This study focuses on the mechanism of release of the stored mechanical energy of a polymer, which is identified as the driving force for the chemo-responsive shape memory effect and inductive decrease in glass transition temperature of SMPU in response to the water.

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

“…Emerging trends such as using biodegradable polymers that respond to solvents are gaining interest [97] owing to their excellent biological properties that make them apt for typical biomedical applications. Ten years ago, the use of solvents had widened the avenue to develop stimuli-responsive polymers that can actuate without heat, and we speculate with the introduction of a variety of solvents, and "multi stimuli-responsive properties" shall further evolve this realm of science, thereby developing more robust and versatile shape-changing polymers.…”

Study on the moisture absorption of zwitterionic copolymers for moisture‐sensitive shape memory applications

“…Recently, Wang et al investigated the water‐induced shape memory effect (SME) in sodium dodecyl sulfate/epoxy composites . Lu et al also reported the chemo‐responsive SME in shape memory polyurethane triggered by inductive release of mechanical energy storage via copper (II) chloride migration . By utilizing the features of thermo/moisture‐responsive SMPs, Sun et al proposed a concept of incorporating micro‐sized devices made of SMPs that were delivered into living cells for surgery or operation .…”

The Difference in Molecular Orientation and Interphase Structure of SiO2/Shape Memory Polyurethane in Original, Programmed and Recovered States during Shape Memory Process

“…However, it can be noted that the crystallinity and crystallite size of the recovered SiO 2 /SMPU composite were slightly lower than those of the original states, which indicates that the recovered SiO 2 /SMPU sample does not completely restore to its original shape. This is because the movement and agglomeration of some SiO 2 particles lead the pore walls to be damaged, resulting in crystal loss and a decrease in the crystallinity of the recovered SiO 2 /SMPU composite [ 26 ]. Although the programming process can cause partial damage, it can improve the intermolecular interaction forces to make the SiO 2 /SMPU composites show stronger mechanical properties.…”