Hierarchical anti-adhesive materials by mimicking insect traps

模仿昆虫陷阱的分层防粘材料

• 批准号: 128306512
• 负责人: Professor Dr. Stanislav N. Gorb
• 金额: --
• 依托单位: Institut für Chemie neuer Materialien
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2015-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/128306512?language=en
• 关键词: Hierarchical; anti; adhesive; materials; mimicking

We aim at elucidation of structure/property relations in hierarchically organised anti-adhesive trapping organs of carnivorous pitcher plants and at the design of bio-inspired prototypes. Structural characterisation of all three hierarchical levels (level 1: lunate cells; level 2: lower wax layer; level 3: upper wax layer) in pitchers of the model plant Nepenthes alata was completed, successive stages in the development of the complex wax coverage were determined, and the absence of the regeneration ability in the lower wax layer was shown. We examined adhesive properties of the complete hierarchical system on the global scale by probing insect attachment and demonstrated specific anisotropic properties of biological level 1. We performed physicochemical and mechanical characterisation of levels 2 and 3 on the local scale and developed an experimental approach for measuring adhesion forces on surfaces with very low adhesive capability. Level 1 lunate cells were mimicked by mechanically stable arrays of polymer spheres. The adhesion of the latter was one order of magnitude lower than that of flat controls, even without the anisotropy of biological level 1 lunate cells. Level 2 in both the biological model and bio-inspired systems does not reduce adhesion. For the biological model reduced adhesion is only found for combinations of lower and upper wax layers (levels 2 and 3). We will implement nanorod coatings as bio-inspired level 3 in artificial anti-adhesives that may allow for reliable one-time detachment of adhering surfaces, for example, in the presence of ice.We will evaluate the absorption ability of different wax layers in N. alata pitchers and the influence of the wax crystal size on adhesion at global and local scales. Microstructure and wetting properties of different functional pitcher surfaces in plants from other carnivorous genera will be characterized. To study the role of fluids at the contact interface of bio-inspired anti-adhesives, single bio-inspired hierarchical levels and combinations thereof containing continuous pore systems will be made by swelling-induced morphology reconstruction of block copolymers. The bio-inspired samples will be characterized by light microscopy, scanning electron microscopy, atomic force microscopy, white light interferometry, and contact angle measurements. Pull-off force tests will be carried out under dry conditions and in the presence of water at the contact interface. We will systematically elucidate the effect of (1) the bio-inspired level 3, (2) the interplay of the bio-inspired level 3 with other hierarchical levels, (3) the fluid at the contact zone, and (4) the polarity/hydrophilicity of the surface on anti-adhesive properties of bio-inspired samples under dry and wet conditions. Porous bio-inspired anti-adhesives will be systematically compared with their solid counterparts.

我们的目标是阐明肉食性猪笼草分层组织的抗粘附捕获器官的结构/性质关系，并设计仿生原型。模型植物翼状猪笼草捕虫笼的所有三个层级（第 1 级：月状细胞；第 2 级：下蜡层；第 3 级：上蜡层）的结构表征已完成，复杂蜡覆盖层发育的连续阶段已完成测定结果表明，下层蜡层不具有再生能力。我们通过探测昆虫附着，在全球范围内检查了完整分级系统的粘合特性，并证明了生物级别 1 的特定各向异性特性。我们在局部规模上对级别 2 和 3 进行了物理化学和机械表征，并开发了一种测量粘附力的实验方法作用在粘合能力极低的表面上的力。 1 级月骨细胞由机械稳定的聚合物球阵列模拟。即使没有生物1级月骨细胞的各向异性，后者的粘附力也比平坦对照低一个数量级。生物模型和仿生系统中的 2 级不会降低粘附力。对于生物模型，仅在下蜡层和上蜡层的组合（2 级和 3 级）中发现粘附力降低。我们将在人造抗粘剂中采用仿生 3 级纳米棒涂层，例如在有冰存在的情况下，可以可靠地一次性分离粘附表面。我们将评估不同蜡层在 N 中的吸收能力翼状捕虫笼以及蜡晶体尺寸对全局和局部尺度粘附力的影响。将表征其他肉食属植物不同功能的捕虫笼表面的微观结构和润湿特性。为了研究流体在仿生抗粘剂接触界面上的作用，将通过嵌段共聚物的溶胀诱导形态重建来制备包含连续孔系统的单个仿生分层水平及其组合。仿生样品将通过光学显微镜、扫描电子显微镜、原子力显微镜、白光干涉测量和接触角测量进行表征。拉脱力测试将在干燥条件下且接触界面存在水的情况下进行。我们将系统地阐明 (1) 仿生级别 3、(2) 仿生级别 3 与其他层级的相互作用、(3) 接触区的流体以及 (4) 极性的影响/表面亲水性对仿生样品在干燥和潮湿条件下的抗粘附性能的影响。多孔仿生抗粘剂将与其固体对应物进行系统比较。