Recently, multi-shape-memory polymers have attracted significant attention due to their technological impact. This study reports novel zwitterionic multi-shape-memory polyurethanes (ZSMPUs) from N-methyldiethanolamine (MDEA), hexamethylene diisocyanate (HDI) and 1,3-propanesultone (PS). The ZSMPUs feature excellent multi-shape-memory properties that are capable of remembering four different shapes, and shape recovery decreases with increasing sulfobetaine content. Ionic interactions greatly influence the structure, morphology and properties. Increasing the sulfobetaine content promotes the phase mixing and zwitterions serve as organic fillers in the zwitterionic polyurethane. Immersing the zwitterionic polyurethane in moisture-rich conditions and drying at low temperature preserves the shape-memory capabilities and demonstrates good self-healing properties. Furthermore, both the shape memory effect and self-healing effects are repeatable. The self-healing mechanism is ascribed to the spontaneous attraction of zwitterions, followed by slower re-entanglement.

•Novel zwitterionic polyurethane is prepared successfully from N-methyldiethanolamine, etc.•Zwitterionic polyurethane contains sulfobetaine groups for biomedical applications.•Zwitterionic polyurethane shows both good biocompatibility and antibacterial activity.Zwitterionic polyurethanes show great potential applications in biomedical field. This paper reports a novel approach to prepare zwitterionic polyurethanes from N-methyldiethanolamine (MDEA), hexamethylene diisocyanate (HDI) and 1,3-propanesultone (1,3-PS). Results show that sulfobetaine groups are successfully grafted onto the MDEA based polyurethanes. The introduction of sulfobetaine group improves cell biocompatibility of polyurethanes. Moreover, good antibacterial activity of zwitterions is retained in this MDEA based polyurethanes. This work provides another substantiation to integrate antimicrobial and non-fouling properties.

Supramolecular liquid crystalline polymers and shape memory polymers are attracting increasing interest as materials. In this paper, we describe the development of a supramolecular liquid crystalline shape memory polyurethane (SLCSMPU) complex that exhibits both liquid crystalline properties and shape memory properties. The complex is formed by incorporating 4-hexadecyloxybenzoic acid (HOBA) into a pyridine-containing shape memory polyurethane (PySMPU). The HOBA is tethered to the PySMPU by strong hydrogen bonding between the pyridine rings and the COOH of the HOBA, forming a SLCSMPU complex. Heat treatment plays an important role in the formation of hydrogen-bonded supramolecular liquid crystalline structures in these SLCSMPU complexes. Thus, the SLCSMPU complex not only maintains the intrinsic liquid-crystalline properties of HOBA, but can also form a stable polymeric film for various shape memory applications. Additionally, the SLCSMPU complex forms a two-phase separated structure composed of an amorphous polyurethane matrix and a HOBA crystalline phase, which includes the hydrogen-bonded crystalline HOBA phase and the free HOBA crystalline phase. Therefore, a simple one-step programming process is developed that produces SLCSMPU complexes with excited triple-shape functionalities due to their multiple phase transitions, especially when the molar ratio of HOBA/BINA is less than 0.8.

Recently, multi-shape-memory polymers have attracted significant attention due to their technological impact. This study reports novel zwitterionic multi-shape-memory polyurethanes (ZSMPUs) from N-methyldiethanolamine (MDEA), hexamethylene diisocyanate (HDI) and 1,3-propanesultone (PS). The ZSMPUs feature excellent multi-shape-memory properties that are capable of remembering four different shapes, and shape recovery decreases with increasing sulfobetaine content. Ionic interactions greatly influence the structure, morphology and properties. Increasing the sulfobetaine content promotes the phase mixing and zwitterions serve as organic fillers in the zwitterionic polyurethane. Immersing the zwitterionic polyurethane in moisture-rich conditions and drying at low temperature preserves the shape-memory capabilities and demonstrates good self-healing properties. Furthermore, both the shape memory effect and self-healing effects are repeatable. The self-healing mechanism is ascribed to the spontaneous attraction of zwitterions, followed by slower re-entanglement.

Supramolecular liquid crystalline polymers and shape memory polymers are attracting increasing interest as materials. In this paper, we describe the development of a supramolecular liquid crystalline shape memory polyurethane (SLCSMPU) complex that exhibits both liquid crystalline properties and shape memory properties. The complex is formed by incorporating 4-hexadecyloxybenzoic acid (HOBA) into a pyridine-containing shape memory polyurethane (PySMPU). The HOBA is tethered to the PySMPU by strong hydrogen bonding between the pyridine rings and the COOH of the HOBA, forming a SLCSMPU complex. Heat treatment plays an important role in the formation of hydrogen-bonded supramolecular liquid crystalline structures in these SLCSMPU complexes. Thus, the SLCSMPU complex not only maintains the intrinsic liquid-crystalline properties of HOBA, but can also form a stable polymeric film for various shape memory applications. Additionally, the SLCSMPU complex forms a two-phase separated structure composed of an amorphous polyurethane matrix and a HOBA crystalline phase, which includes the hydrogen-bonded crystalline HOBA phase and the free HOBA crystalline phase. Therefore, a simple one-step programming process is developed that produces SLCSMPU complexes with excited triple-shape functionalities due to their multiple phase transitions, especially when the molar ratio of HOBA/BINA is less than 0.8.