Sodium dodecyl sulfate/epoxy composite: water-induced shape memory effect and its mechanism

With the aim of integrating a family of functional composites, possessing a conspicuous water-induced shape memory effect (SME), a novel sodium dodecyl sulfate-epoxy shape memory composite was constructed. The original fabrication strategy of the composite was designed based on the chemical interaction constructed 3D microvoid on the shape memory composite surface. Compared with the pure epoxy shape memory polymer, the composites display a gratifying water-induced shape memory effect. The results indicate that the water-induced shape recovery rate of the composite is accelerated through increasing the temperature or decreasing the specimen thickness. An immersion test in water suggests that the chemical interaction and physical swelling effect have a significant influence on the water-induced shape memory process. This research advocates the design concept and presents some experimental results of the water-driven smart composite. The potential application range is expected to expand more widely, including a humidity sensor, temperature/humidity switch, underwater deployable structure and a power source transforming chemical energy into mechanical energy for an ultralow-power device.