State Key Laboratory of Heavy Oil Processing, China University of Petroleum (Beijing), Beijing 102249, China.
College of Mechanical Transportation Engineering, China University of Petroleum (Beijing), Beijing 102249, China.
Langmuir. 2021 Jul 20;37(28):8410-8416. doi: 10.1021/acs.langmuir.1c00568. Epub 2021 Jul 2.
Strong, reversible, and self-cleaning adhesion in the toe pads of geckos allow the lizards to climb on a variety of vertical and inverted surfaces, regardless of the surface conditions, whether hydrophobic or hydrophilic, smooth or tough, wet or dry, clean or dirty. Development of synthetic gecko-inspired surfaces has drawn a great attention over the past two decades. Despite many external-stimuli responsive mechanisms (i.e., thermal, electrical, magnetic) have been successfully demonstrated, smart adhesives controlled by light signals still substantially lag behind. Here, in this report, we integrate tetramethylpiperidinyloxyl (TEMPO)-doped polydopamine (PDA), namely, TDPDA, with PDMS micropillars using a template-assisted casting method, to achieve both improved adhesion and self-cleaning performances. To the best of our knowledge, this is the first report on PDA being used as a doping nanoparticle in bioinspired adhesive surfaces to achieve highly efficient self-cleaning controllable by light signals. Notably, the adhesion of the 5% TDPDA-PDMS sample is ∼688.75% higher than that of the pure PDMS at the individual pillar level, which helps to explain the highly efficient self-cleaning mechanism. The sample surfaces (named TDPDA-PDMS) can efficiently absorb 808 nm wavelength of light and heat up from 25 °C to 80.9 °C in 3 min with NIR irradiation. The temperature rise causes significant reduction of adhesion, which results in outstanding self-cleaning rate of up to 55.8% within five steps. The exploration of the photoenabled switching mechanism with outstanding sensitivity may bring the biomimetic smart surfaces into a new dimension, rendering varied applications, e.g., in miniaturized climbing robot, artificial intelligence programmable manipulation/assembly/filtration, active self-cleaning solar panels, including high output sensors and devices in many engineering and biomedical frontiers.
壁虎脚趾垫具有强大、可逆和自清洁的粘附力，使蜥蜴能够在各种垂直和倒置的表面上攀爬，无论表面条件是疏水还是亲水、光滑还是粗糙、湿润还是干燥、清洁还是肮脏。过去二十年来，人们对合成壁虎启发式表面的开发产生了浓厚的兴趣。尽管已经成功展示了许多外部刺激响应机制（即热、电、磁），但受光信号控制的智能粘合剂仍远远落后。在本报告中，我们使用模板辅助浇铸法将四甲基哌啶氮氧自由基（TEMPO）掺杂的聚多巴胺（PDA），即 TDPDA，与 PDMS 微柱集成在一起，以实现改进的粘附力和自清洁性能。据我们所知，这是首次将 PDA 用作仿生粘附表面中的掺杂纳米颗粒，以实现高效的自清洁，受光信号控制。值得注意的是，5%TDPDA-PDMS 样品的粘附力在单个支柱水平上比纯 PDMS 高约 688.75%，这有助于解释高效自清洁机制。样品表面（命名为 TDPDA-PDMS）可以有效地吸收 808nm 波长的光，并在 NIR 照射下在 3 分钟内从 25°C 升温至 80.9°C。温度升高导致粘附力显著降低，从而在五个步骤内实现高达 55.8%的出色自清洁率。对具有出色灵敏度的光启用开关机制的探索可能会将仿生智能表面带入一个新的维度，从而实现各种应用，例如在小型攀爬机器人、人工智能可编程操作/组装/过滤、主动自清洁太阳能电池板中，包括在许多工程和生物医学前沿中的高输出传感器和设备。
