Zhang Xi, Aziz Shazed, Salahuddin Bidita, Zhu Zhonghua
School of Chemical Engineering, The University of Queensland, Brisbane, QLD 4072, Australia.
ACS Appl Mater Interfaces. 2024 Oct 30;16(43):59202-59215. doi: 10.1021/acsami.4c11779. Epub 2024 Oct 22.
Soft actuators made of thermoresponsive polymers have great potential for intelligent robotics and biomedical devices due to their reversible deformation capability in response to temperature fluctuations. However, they are constrained by a predefined phase transition temperature, limited directional deformation, and nonbiocompatible formulations, thereby restricting their practical utility. Herein a new biomimicry approach is presented to overcome these limitations by developing hydro- and hydrothermally responsive soft actuators made of biocompatible and pliable materials i.e. cotton yarn and polyurethane. We mimic the tubular shape of elephant trunks with their unique muscle orientation by embedding a helical cotton yarn within a hydrophilic polyurethane tube, followed by targeted surface patterning. Unlike the narrow-range shape morphing across the phase transition temperature boundary of typical thermoresponsive hydrogel actuators, we harness hydrothermal stiffness variations in polyurethane to obtain consistent morphing capabilities over a much wider temperature range. The developed actuators can perform versatile activities such as linear, bending, curvilinear, and rotating movements, overcoming the unidirectional motion limitations of conventional soft actuators. The cell viability assay on the building block materials also confirms the high biocompatibility of the actuators. The reported facile fabrication strategy provides new insights for designing complex yet free-standing soft actuators from readily available supple materials.
由热响应性聚合物制成的软致动器因其能响应温度波动而产生可逆变形，在智能机器人和生物医学设备领域具有巨大潜力。然而，它们受到预定义的相变温度、有限的定向变形和非生物相容性配方的限制，从而限制了其实际应用。在此，我们提出一种新的仿生方法，通过开发由生物相容性和柔韧性材料（即棉纱和聚氨酯）制成的水响应和水热响应软致动器来克服这些限制。我们通过将螺旋棉纱嵌入亲水性聚氨酯管中，然后进行有针对性的表面图案化，来模仿象鼻的管状形状及其独特的肌肉取向。与典型热响应水凝胶致动器在相变温度边界处的窄范围形状变形不同，我们利用聚氨酯中的水热刚度变化，在更宽的温度范围内获得一致的变形能力。所开发的致动器可以执行多种活动，如线性、弯曲、曲线和旋转运动，克服了传统软致动器的单向运动限制。对构建材料的细胞活力测定也证实了致动器具有高生物相容性。所报道的简便制造策略为用易于获得的柔软材料设计复杂但独立的软致动器提供了新的思路。
