基底弹性形变对纳米气泡界面形貌和力学性质影响的研究

The astonishing large contact angle and high stability of interfacial nanobubbles at the solid-liquid interface, because of their significances and potential applications in the fields of the industry, biology, medicine, and environment, have become very hot topics studied by many researchers. Contact line pinning is theoretically assumed to be one of the key factors to induce the abnormalities of interfacial nanobubbles. The substrate elastic deformation can change the contact line pinning of nanobubbles on the substrates, and consequently, significantly affects the interfacial morphology, mechanical property and stability of nanobubbles. Based on our previous advantages on interfacial nanobubbles, the present project will, combining multiple modes of atomic force microscopy (AFM), in situ and quantitatively study the interfacial morphology and mechanical property of nanobubbles on soft substrates. Through a systematical investigation of the effect of the substrate elastic deformation due to the changes of substrates Young’s modulus, liquids surface tension and nanobubbles size on the contact line pinning of nanobubbles, a complete contact line pinning model with the substrate elastic deformation included of nanobubbles on soft substrates will be constructed based on the experimental and theoretical analysis. This study will be helpful to deeply understand the contact line pinning theory of interfacial nanobubbles, so as to explain their abnormalities. It will also offer a reference for the practical applications of interfacial nanobubbles with soft materials.

固液界面纳米气泡的奇异性——超大接触角和超高稳定性，由于其在工业、生物、医学和环境等领域中的重要意义和潜在应用，已成为多学科科研工作者的研究热点。理论研究认为接触线钉扎是导致界面纳米气泡奇异性的关键因素之一。基底弹性形变会改变纳米气泡在基底上的接触线钉扎特性，从而对纳米气泡的界面形貌、力学性质和稳定性产生重要影响。本项目基于前期纳米气泡研究的优势，拟结合多种模式的原子力显微镜（AFM）技术原位定量地研究软基底上纳米气泡的接触线钉扎特性，通过系统探讨由于基底杨氏模量、液体表面张力及纳米气泡尺寸的改变引起的基底弹性形变对纳米气泡界面形貌和力学性质的影响，结合理论分析构建软基底上含基底弹性形变的纳米气泡接触线钉扎模型。该研究将有助于深入理解固液界面纳米气泡的接触线钉扎理论，揭示界面纳米气泡奇异性的物理机制，并为开展界面纳米气泡与软材料相结合的实际应用提供参考。

纳米气泡、纳米弯液面和纳米液滴具有类似的纳米尺度液气界面，对其界面特性的研究不仅在从微观角度上理解宏观润湿现象方面有重要的科学意义，而且在工业、环境和生物医学等领域可能具有重要的潜在应用价值。本项目研究了界面纳米气泡的力学性质，建立了基于原子力显微镜（AFM）技术鉴别纳米液滴、纳米气泡和微固颗粒的实验方法，测量了纳米气泡的刚度，从理论上解释了纳米气泡刚度对其尺寸的依赖性。通过测量纳米孔中纳米弯液面的刚度和研究纳米多孔表面的宏观润湿转变，将微观表界面性质定量地与宏观的润湿特性相联系，揭示了微观表界面性质对固体宏观润湿行为的调控机制，对超疏水材料的设计和应用具有重要的指导意义。建立了基于AFM技术精确测量软表面弹性毛细形变的实验方法，从实验上首次发现了软表面形变的弹性-毛细转变，将为微流控器件、软体机器人及软光刻技术的设计创新提供可能的新思路。