Preparation of superhydrophobic titanium surface via the combined modification of hierarchical micro/nanopatterning and fluorination

Zhen Wang,Bing Ren

doi:10.1007/s11998-021-00576-9

Abstract

Adhesion of bacteria and platelets on blood-contact implants and surgical devices is one of the causes of infections and thrombus. A superhydrophobic surface serving as a protective layer can minimize adhesion and contamination due to the low surface energy. The objective of this paper is to construct a superhydrophobic surface on a titanium implant by a combination of a topological structure and chemical coating. First, a micro/nano hierarchical morphology is obtained by sandblasting, acid-etching, and anodic oxidation. Then, a low surface energy coating material (fluoroalkylsilane, as the example case in this study) is used to modify the surface further. The effects of the morphology of micro and/or nanoscales and corresponding fluorination on the wettability are investigated. The results show that a hierarchical surface with microroughness and nanotubes is successfully constructed, and the contact angle (CA) is 44.9°, indicating good hydrophilicity. Interestingly, after being modified by fluoroalkylsilane, the surface converted from hydrophilic to superhydrophobic with a CA of 151.4°. In contrast, the fluorination modification of single micro or nanofeatures cannot achieve superhydrophobicity, indicating that the micro/nanostructures may show a synergistic effect for an efficient fluorination coating later on. Overall, our results demonstrate the feasibility of achieving a superhydrophobic surface via the micro/nano topological patterning and fluorination modification. The proposed method is expected to enrich the preparation technologies of superhydrophobic titanium surfaces.Graphic abstract

Highlights

Preparation technology of superhydrophobic surfaces has been inspired by various objects in nature like lotus leaves, cicada wings, and rice foliage, which have unique wettability with water contact angles (CA) above 150°
The preparation of superhydrophobic Ti surfaces is essential for further biomedical applications in the future
A superhydrophobic surface was successfully prepared on Ti substrates by the combined modification of micro/nanoengineering and fluorination

Summary

Introduction

Preparation technology of superhydrophobic surfaces has been inspired by various objects in nature like lotus leaves, cicada wings, and rice foliage, which have unique wettability with water contact angles (CA) above 150°.1–4 Many special functions of these surfaces, such as low adhesion, reduced drag, and self-cleaning, have been found to be attributed to the superhydrophobicity.[2,5,6] the preparation of superhydrophobic surfaces has attracted considerable attention for the promising application in pipeline protection,[7] shipbuilding,[8] and biomedical instruments.[9]. Thrombotic occlusion of the stented vessel segment can lead to in-stent restenosis, which is one of the implantation’s major failures and highly risky to the patients.[18,19] As a result, surface modification is essential to improve the antithrombogenic properties by creating a protective layer at the interface.[20] It has been reported that superhydrophobic surfaces can be utilized to improve blood compatibility and anticoagulation performance,[21,22] and reduce the adhesion of bacteria, minimizing the risk of implant-associated infections.[23] the preparation of superhydrophobic Ti surfaces is essential for further biomedical applications in the future

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Conclusion