Zhang Qinghua/Zhan Xiaoli, Zhejiang University, "AFM": Supramolecular Smart SLIPS Marine Antifouling Coatings Inspired by Hagfish: Lubrication Mode Response Switching and Self-healing Performance

Biological pollution has had a serious negative impact on all aspects of human activities, especially on human marine affairs

Recently, the research group of Prof.

Scheme 1.

When stimulated by a predator (mechanical stimulation, light stimulation, etc.

Scheme 2.

【Synthesis process of antifouling paint】

The synthesis process of Azo-modified silicone PU (AzoPU) and acetylated α-CD (AcCD)-modified silicone PU (ACDPU) is shown in Scheme 2

Figure 1.

【Characterization of Surface Elements】

Through the characterization of surface elements before and after the coating response, the lubrication response percolation performance of the coating was verified

Figure 2.

【Surface Morphology Characterization】

The lubricant-responsive leakage of the coatings was demonstrated by characterization of the surface morphologies of the coatings before and after the reaction

Figure 3.

【Responsive switching performance of surface lubrication and wettability】

Responsive leakage of lubricant on the surface also alters the surface lubricity, causing changes in macroscopic properties (WCA and droplet sliding properties)

In addition, some comparative experiments were also performed to demonstrate that this reaction process is caused by the supramolecular interaction of Azo & AcCD under visible light/heating stimulation
.
As shown in Fig.
3c, the droplet sliding speed of the coating increased after visible light or heating, while the droplet sliding speed did not change significantly under dark and unheated conditions
.
These comparative experiments show that the stimulatory effect of visible light/heating on the coating is necessary to induce the penetration of silicone oil
.

Figure 4.
Stability of AzoAcCDPU-15 by silicone oils of different viscosities: a) pH, b) salinity, c) centrifugation, d) dynamic washing (200 rpm); AzoAcCDPU-15 passed e) visible light f) 50°C Hot lubricating oil responds to cyclic self-replenishing properties
.

【Stability and cycle performance】

One of the most important factors affecting the application of slip coatings is insufficient stability
.
"v (mm s-1)" on the y-axis represents the speed at which the water droplet slides over the coating at a certain inclination angle (30°)
.
The main body of the coating substrate and lubricant is PDMS
.
Due to the excellent chemical inertness of PDMS, the lubricity of the coating surface is not affected by the pH (0-14) and salinity (0-7 wt.
%) of the article seawater (ASW), as shown in Fig.
4a,b
.
The stability against external mechanical action (centrifugation and washing) is shown in Fig.
4c,d
.
The stability between the lubricant and the matrix is ​​significantly enhanced due to the proper compatibility of the silicone oil with the PDMS-based matrix, as well as the capillary force between the microcavities and the lubricant stored in the matrix
.
The performance of the cyclic response is shown in Fig.
4e,f
.
In at least 10 "swabbing-response" cycles, the coating could respond repeatedly after removing the surface lubricating layer, demonstrating the reproducibility of the coating's response performance
.

Figure 5.
a) Digital photographs of UV (350 nm), heat (50 °C) cured PU; b) Repair efficiency (RE) and Young's modulus of repaired coatings; c) AzoAcCDPU-0/10/15/20 Digital photo of the healing process under 350 nm UV
.

Figure 6.
Self-cleaning performance of AzoACCDPU-15 (slide size: 25.
4 mm × 76.
2 mm) on a) solid model contaminants and b) liquid model contaminants; c) fluorescence microscope photographs and d) quantitative absorbance-concentration test coating Anti-protein (BSA) adhesion properties of the layer
.

Figure 7.
Performance of PDMS and antifouling paint against E.
coli adhesion: a) LB plate (9 cm diameter) method; b) SEM observation; PDMS and antifouling paint against S.
aureus adhesion: c) LB Plate method d) SEM observation
.

【summary】

In conclusion, hagfish-inspired supramolecular slipsomes were prepared in this study as marine antifouling coatings
.
Due to the responsive supramolecular interaction between azo and α-CD, the smart coating can tune the surface lubricity, switch between "enhanced" and "normal" antifouling modes, and can adapt to different antifouling needs, Optimized for durability
.
Compared with traditional low SE antifouling coatings, this smart SLIPS maintains efficient self-healing effect and responsive antifouling performance, improving practical shallow sea application performance in boom season 180 days
.
This study provides an effective strategy for designing "smart" antifouling coatings, which are expected to be applied in marine, medical, biological and other fields
.