A shape-memory polymer (SMP) named DCSM was developed by incorporating mechanically interlocked [c2] daisy chains into the backbone of a polymer network. This material exhibits remarkable shape-memory properties under thermal control. The [c2] daisy chain crosslinks play a crucial role in driving the shape memory function by increasing the glass transition temperature (Tg) and enabling the storage and dissipation of entropic energy. The supramolecular host-guest interactions within the [c2] daisy chain topology enhance mechanical strength, network stability, and shape recovery properties, while also providing fatigue resistance. The [c2] daisy chain unit, as a building block, has the potential to enable the development of a wide range of shape-memory polymer materials.
The DCSM polymer was synthesized using a photo-induced thiol-ene click reaction between a four-arm sulfydryl monomer and a mechanically interlocked diene bearing dibenzo-24-crown-8 (DB24C8) rings as the supramolecular hosts and ammoniums as the guests. The resulting SMP exhibits excellent shape fixity (Rf) and shape recovery (Rr) values, and can be molded into various predetermined shapes. The DCSM polymer demonstrates its potential as an actuator for releasing and lifting objects. Three control groups were employed to elucidate the role of the [c2] daisy chain topology and the host-guest recognitions in driving the shape memory properties. The [c2] daisy chain topology contributes to the increase of Tg, which is essential in the entropy-driven shape memory effect. The presence of host-guest interactions within the [c2] daisy chain crosslinks greatly increases the mechanical performance and leads to remarkable shape recovery properties and fatigue resistance.
The DCSM polymer was characterized using various techniques, including thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The DCSM polymer exhibited a glass transition temperature (Tg) of around 40°C and a broad endothermic peak at around 90°C associated with the dissociation of host-guest recognition. The DCSM polymer could be used as a potential shape memory material, with a shape fixity of 98.8% and a shape recovery value of 98.6%. The DCSM polymer also demonstrated highly consistent reversible actuation after multiple shape-memory cycles. The recovery kinetics of the shape-memory polymer were investigated, and the DCSM film underwent a 100% shape recovery within a short period (<35 s) when the activation temperature was above 80°C. The DCSM polymer was also able to lift objects, demonstrating its potential in soft robotics through programming stimuli-responsive motions. The DCSM polymer was found to have a maximum tensile strength of 14.2 MPaA shape-memory polymer (SMP) named DCSM was developed by incorporating mechanically interlocked [c2] daisy chains into the backbone of a polymer network. This material exhibits remarkable shape-memory properties under thermal control. The [c2] daisy chain crosslinks play a crucial role in driving the shape memory function by increasing the glass transition temperature (Tg) and enabling the storage and dissipation of entropic energy. The supramolecular host-guest interactions within the [c2] daisy chain topology enhance mechanical strength, network stability, and shape recovery properties, while also providing fatigue resistance. The [c2] daisy chain unit, as a building block, has the potential to enable the development of a wide range of shape-memory polymer materials.
The DCSM polymer was synthesized using a photo-induced thiol-ene click reaction between a four-arm sulfydryl monomer and a mechanically interlocked diene bearing dibenzo-24-crown-8 (DB24C8) rings as the supramolecular hosts and ammoniums as the guests. The resulting SMP exhibits excellent shape fixity (Rf) and shape recovery (Rr) values, and can be molded into various predetermined shapes. The DCSM polymer demonstrates its potential as an actuator for releasing and lifting objects. Three control groups were employed to elucidate the role of the [c2] daisy chain topology and the host-guest recognitions in driving the shape memory properties. The [c2] daisy chain topology contributes to the increase of Tg, which is essential in the entropy-driven shape memory effect. The presence of host-guest interactions within the [c2] daisy chain crosslinks greatly increases the mechanical performance and leads to remarkable shape recovery properties and fatigue resistance.
The DCSM polymer was characterized using various techniques, including thermal gravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The DCSM polymer exhibited a glass transition temperature (Tg) of around 40°C and a broad endothermic peak at around 90°C associated with the dissociation of host-guest recognition. The DCSM polymer could be used as a potential shape memory material, with a shape fixity of 98.8% and a shape recovery value of 98.6%. The DCSM polymer also demonstrated highly consistent reversible actuation after multiple shape-memory cycles. The recovery kinetics of the shape-memory polymer were investigated, and the DCSM film underwent a 100% shape recovery within a short period (<35 s) when the activation temperature was above 80°C. The DCSM polymer was also able to lift objects, demonstrating its potential in soft robotics through programming stimuli-responsive motions. The DCSM polymer was found to have a maximum tensile strength of 14.2 MPa