ABSTRACT
Embedded with an Optical Fiber ................................................ 143 6.4 Electrically Induced Shape-Memory Effect ........................................... 147
6.4.1 Shape-Memory Polymer Filled with Carbon Nanotubes ........ 147 6.4.2 Shape-Memory Polymer Filled with Carbon Particles ............. 149
6.4.2.1 Differential Thermal Scanning Behavior .................... 150 6.4.2.2 Dynamic Mechanical Performances ............................ 150 6.4.2.3 Micro/Nanopatterns of SMP Composite ..................... 152 6.4.2.4 Electroactive Properties for Shape-Memory Effect .... 153
6.4.3 Shape-Memory Polymer Filled with Electromagnetic Fillers ............................................................................................... 156 6.4.3.1 Electromagnetic-Induced SMP Composite .................. 156 6.4.3.2 Electroactive Thermoplastic SMP Composite
Filled with Ni Powder Chains ....................................... 157 6.4.3.3 Electroactive Thermoplastic SMP/CB Composite
Filled with Ni Powder Chains ....................................... 165 6.4.3.4 Electroactive Thermoset SMP Composite Filled
with Ni Powder Chains .................................................. 167 6.4.3.5 SMP Composite Actuated by External Magnetic
Force .................................................................................. 169 6.4.4 Shape-Memory Polymer Filled with Hybrid Fibers ................. 171
Shape-memory polymer (SMP) is specially implied to thermal responsive SMP, of which the shape recovery actuation is always a thermal-induced process, though it can be triggered electrically [1], magnetically [2], or electromagnetically [3]. For some special type of SMPs that are incorporated with photoresponsive monomers can be induced by light with characteristic wavelength. For the SMP composites lled with functional ller or llers in composites are activated by corresponding stimuli such as electric, magnetic, or electromagnetic eld and thereby an inductive thermal effect is indirectly when the composites were heated above the transition temperature by inductive thermal heating, the recovery behavior occurs. Finkelmann et al. [4,5] reported a shape-memory liquid-crystalline (LC) elastomer that can be triggered by light through incorporating azo groups into the LC mesogens. Upon ultraviolet (UV) illumination, the azo groups isomerize to the con guration and sharply bend the mesogens, hampering the nematic ordering. Correspondingly, the material undergoes a photo-induced nematic-isotropic transition, accompanied with a large shape change. Recently, as shown in Figure 6.1, Lendlein et al. [6] reported a novel SMP that is in response to light by introducing molecular switches such as cinnamic acid [7] and cinnamylidene acetic acid [8]. The latter compounds have the capability of undergoing ef cient photoreversible cycloaddition reactions when exposed to alternating wavelengths (k > 260 nm or k < 260 nm). The temporary shape of LC is kept resulting from the formation of new photo-responsive cross-links, while the photo-responsive cross-links can be reversibly cleaved by a UV light irradiation with a wavelength shorter than 260 nm, leading to regaining the original shape. The unique characteristics of the above-mentioned SMPs enable the shape recovery to be driven at ambient temperatures by remote activation rather than external heating; this method eliminates temperature constraints for biomedical and other applications.
