Nanotechnology Research Laboratory, Research School of Engineering , The Australian National University , Canberra ACT 2601 , Australia.
Max Planck Institute for Polymer Research , Ackermannweg 10 , D-55128 Mainz , Germany.
Nano Lett. 2019 Mar 13;19(3):1892-1901. doi: 10.1021/acs.nanolett.8b04972. Epub 2019 Feb 12.
Super-hydrophobic, super-oleo(amphi)phobic, and super-omniphobic materials are universally important in the fields of science and engineering. Despite rapid advancements, gaps of understanding still exist between each distinctive wetting state. The transition of super-hydrophobicity to super-(oleo-, amphi-, and omni-)phobicity typically requires the use of re-entrant features. Today, re-entrant geometry induced super-(amphi- and omni-)phobicity is well-supported by both experiments and theory. However, owing to geometrical complexities, the concept of re-entrant geometry forms a dogma that limits the industrial progress of these unique states of wettability. Moreover, a key fundamental question remains unanswered: are extreme surface chemistry enhancements able to influence super-liquid repellency? Here, this was rigorously tested via an alternative pathway that does not require explicit designer re-entrant features. Highly controllable and tunable vertical network polymerization and functionalization were used to achieve fluoroalkyl densification on nanoparticles. For the first time, relative fluoro-functionalization densities are quantitatively tuned and correlated to super-liquid repellency performance. Step-wise tunable super-amphiphobic nanoparticle films with a Cassie-Baxter state (contact angle of >150° and sliding angle of <10°) against various liquids is demonstrated. This was tested down to very low surface tension liquids to a minimum of ca. 23.8 mN/m. Such findings could eventually lead to the future development of super-(amphi)omniphobic materials that transcend the sole use of re-entrant geometry.
超疏水、超疏油（两亲）和超全疏材料在科学和工程领域具有普遍的重要性。尽管取得了快速进展，但每种独特的润湿状态之间仍然存在理解上的差距。从超疏水性向超（疏油、两亲和全疏）疏水性的转变通常需要使用凹入特征。如今，凹入几何形状引起的超（两亲和全疏）疏水性得到了实验和理论的充分支持。然而，由于几何形状的复杂性，凹入几何形状的概念形成了一种教条，限制了这些独特润湿状态的工业进展。此外，一个关键的基本问题仍然没有答案：极端的表面化学增强是否能够影响超液体排斥性？在这里，通过不需要明确的设计凹入特征的替代途径，对这一问题进行了严格的测试。通过高度可控和可调的垂直网络聚合和功能化，在纳米颗粒上实现了氟烷基的致密化。首次定量地调整了相对氟官能化密度，并将其与超液体排斥性能相关联。展示了具有 Cassie-Baxter 状态（接触角>150°，滑动角<10°）的分步可调谐超两亲纳米粒子薄膜，可抵抗各种液体。这项测试的表面张力低至约 23.8 mN/m。这些发现最终可能导致超（两亲）全疏材料的未来发展，超越了单纯使用凹入几何形状的限制。
