Slippery surfaces provide a new way to solve the adhesion problem. This protocol describes how to fabricate slippery surfaces at high temperatures. The results demonstrate that the slippery surfaces showed anti-wetting for liquids and a remarkable anti-adhesion effect on soft tissues at high temperatures.
Anti-adhesion surfaces with high-temperature resistance have a wide application potential in electrosurgical instruments, engines, and pipelines. A typical anti-wetting superhydrophobic surface easily fails when exposed to a high-temperature liquid. Recently, Nepenthes-inspired slippery surfaces demonstrated a new way to solve the adhesion problem. A lubricant layer on the slippery surface can act as a barrier between the repelled materials and the surface structure. However, the slippery surfaces in previous studies rarely showed high-temperature resistance. Here, we describe a protocol for the preparation of slippery surfaces with high-temperature resistance. A photolithography-assisted method was used to fabricate pillar structures on stainless steel. By functionalizing the surface with saline, a slippery surface was prepared by adding silicone oil. The prepared slippery surface maintained the anti-wetting property for water, even when the surface was heated to 300 °C. Also, the slippery surface exhibited great anti-adhesion effects on soft tissues at high temperatures. This type of slippery surface on stainless steel has applications in medical devices, mechanical equipment, etc.
Anti-adhesion surfaces at high temperatures for use with liquids and soft tissues have received considerable interest because of their extensive application potential in electrosurgical instruments, engines, pipelines etc.1,2,3,4. Bioinspired surfaces, particularly superhydrophobic surfaces, are considered the ideal choice because of their excellent anti-wetting abilities and self-cleaning properties5. In superhydrophobic surfaces, the anti-wetting ability should be ascribed to the locked air in the surface structure. However, the superhydrophobic state is unstable because it is in the Cassie-Baxter state6,7. Also, at high temperatures, the anti-wetting for liquid droplets can fail because of the wetting state transition from the Cassie-Baxter to the Wenzel state8. This wetting transition is induced by small liquid droplet wetting in the structures, which results in the failure to lock the air in place.
Recently, inspired by the slippery properties of the peritome of the pitcher plant, Nepenthes, Wong et al. reported a concept to construct slippery surfaces by infusing a lubricant into the surface structures9,10,11. Due to capillary force, the structures can firmly hold the lubricant in place, just as in the locked air pocket on superhydrophobic surfaces. Thus, the lubricant and surface structures can form a stable solid/liquid surface. When the lubricant has a preferential affinity for the surface structure, the liquid droplet on the composite surface can slide easily, with only a very low contact angle hysteresis (e.g., ~2°)12. This lubricant layer also enables the surface to have remarkable anti-wetting capabilities13, demonstrating great potential for medical devices14,15. However, previous studies on slippery surfaces mainly focused on the preparation for application at room temperature or low temperatures. There are very few studies on the preparation of slippery surfaces with high-temperature resistance. For example, Zhang et al. showed that the rapid evaporation of lubricant rapidly causes the failure of the slippery property at even slightly high temperatures16.
Slippery surfaces with high-temperature resistance can widen the application potential; for example, they can be used as liquid barriers to decrease soft tissue adhesion to electrosurgical instrument tips. During the surgical operation, severe soft tissue adhesion occurs because of the high temperature of the electrosurgical instrument tips. The soft tissue can be charred, causing it to adhere to the instrument tip, which then tears the soft tissue around the tip17,18,19. The adhered soft tissue on the electrosurgical instrument tip negatively influences the operation and also may induce the failure of hemostasis19,20. These effects significantly harm people's health and economic interest. Therefore, solving the issue of soft tissue adhesion to electrosurgical instruments is very urgent. In fact, slippery surfaces offer an opportunity to solve this problem.
Here, we present a protocol to fabricate slippery surfaces available at high temperatures. Stainless steel was selected as the surface material because of its high-temperature resistance. The stainless steel was roughened by photolithography-assisted chemical etching. Then, the surface was functionalized with a biocompatible material, saline octadecyltrichlorosilane (OTS)21,22,23,24. A slippery surface was prepared by adding silicone oil. These materials enabled the slippery surface to achieve high-temperature resistance. The anti-wetting property at high temperatures and the anti-adhesion effects on soft tissue were investigated. The results show the potential of using slippery surfaces to solve the anti-adhesion problem at high temperatures.
This manuscript details protocols for fabricating a slippery surface with high-temperature resistance. The slippery property of our prepared surface was demonstrated by observing the easy-sliding behavior of a water droplet. Then, the anti-wetting of the prepared slippery surface at different high temperatures was investigated by depositing a water droplet on the hot surface. The results show that the prepared slippery surface maintained its slippery property even when it was heated to above 300 °C. We also determin…
The authors have nothing to disclose.
This work was supported by the National Natural Science Foundation of China (Grant No. 51290292) and was also supported by the Academic Excellence Foundation of BUAA for PhD students.
Stainless steel | Hongtu Corporation | 316 | Use as received |
Octadecyltrichlorosilane | Huaxia Reagent | 112-04-9 | Use as received |
Photoresist | Kempur Microelectronic Corporation | 317S | Use as received |
Silicone oil | Beijing Chemical Works | 350 cst | Use as received |
Anhydrous toluene | Beijing Chemical Works | 108-88-3 | Use as received |
Phosphoric acid (H3PO4) | Tianjin Chemical Corporation | 7664-38-2 | Use as received |
Hydrochloric acid (HCl) | Tianjin Chemical Corporation | 7647-01-0 | Use as received |
Ferric chloride (FeCl3) | Tianjin Chemical Corporation | 7705-08-0 | Use as received |
Optical upright microscope | Olympus | BX51 | |
Optical stereo microscope | Olympus | SZX16 | |
High speed camera | Olympus | i-SPEED LT | |
Ultrasonic cleaner | KUNSHAN ULTRASONIC INSTRUMENTS CO. LTD | KQ-500E | |
Dynamometer | Yueqing Handapi Instruments Co. Ltd | HP-5 | |
Manipulator | Yueqing Handapi Instruments Co. Ltd | HLD | |
Hot plate | Shenzhen Jingyihuang Corporation | DRB-1 |