Hybrid Superhydrophobic–Photocatalytic Textile Coatings for Antibacterial, Antiviral, and Self-Cleaning Applications

Dr V Ramesh Babu

Professor, Dept of Textile Technology, 

Kumaraguru College of Technology, Coimbatore, India

Veeralakshmi V, B.Tech,

Department of Textile Technology, 

Kumaraguru college of technology, Coimbatore, India

Abstract

Multifunctional textile surfaces that simultaneously prevent microbial adhesion and actively inactivate pathogens represent a promising direction for next-generation protective fabrics. This study proposes a hybrid coating strategy combining superhydrophobic surface structuring with photocatalytic nanocoatings to achieve antibacterial, antiviral, and self-cleaning functionality within a single textile system. By integrating fluid repellency with light-activated microbial inactivation, the approach aims to minimise pathogen deposition while eliminating residual contaminants. The work focuses on engineering trade-offs between repellency, breathability, and durability, which remain insufficiently quantified in current textile research.

Keywords: multifunctional textiles, photocatalytic coatings, superhydrophobic fabrics, antiviral textiles, hybrid finishes

1. Introduction

Textile surfaces used in healthcare, public transport, and protective apparel are continuously exposed to biological contaminants through droplets, aerosols, and physical contact. Conventional antimicrobial and antiviral finishes primarily rely on chemical activity to neutralise microorganisms after contact. However, this approach does not prevent initial contamination and often suffers from durability and leaching concerns. An alternative strategy involves combining passive and active protection mechanisms within a single textile surface. Passive protection reduces contamination through liquid repellency, while active protection inactivates microorganisms that remain on the surface. Multifunctional hybrid coatings that integrate superhydrophobic behaviour with photocatalytic activity offer a compelling pathway toward this goal. This study explores the design rationale, performance metrics, and practical challenges associated with antibacterial, antiviral, and self-cleaning hybrid textile coatings.

2. Concept of Hybrid Functional Protection

Superhydrophobic textile surfaces are characterised by high water contact angles and low surface energy, causing liquid droplets to bead and roll off the fabric. This behaviour reduces wetting and limits the residence time of pathogen-containing droplets. However, repellency alone cannot guarantee complete protection, as some microorganisms may still adhere to fibres or remain trapped within the fabric structure. Photocatalytic materials such as titanium dioxide (TiO₂) and graphitic carbon nitride (g-C₃N₄) introduce an active disinfection mechanism. Under light exposure, these materials generate reactive oxygen species that can damage bacterial cell walls and viral envelopes, leading to microbial inactivation. Previous studies have demonstrated the antibacterial and antiviral potential of photocatalysts, but their integration into breathable, flexible textiles remains challenging. By combining these two mechanisms, hybrid coatings aim to reduce microbial deposition and actively neutralise surviving contaminants, offering a dual layer of protection. (Fig. 1)

Figure 1: Hybrid Functional Protection 

3. Materials Selection and Design Rationale

The selection of photocatalytic materials is critical to the effectiveness of the hybrid system. TiO₂ is widely studied due to its chemical stability and strong oxidative activity under ultraviolet light. However, its limited visible-light response restricts indoor applications. Graphitic carbon nitride has attracted attention as a visible-light-responsive photocatalyst with lower toxicity and improved compatibility with polymer substrates. For hydrophobic surface engineering, low-surface-energy polymers combined with nanoscale roughness are used to achieve superhydrophobicity. The challenge lies in balancing surface roughness with fabric flexibility and air permeability. Excessive coating thickness or pore blockage can significantly reduce breathability, which is unacceptable for wearable textiles. (Fig. 2)

Figure 2: Photocatalytic materials

4. Proposed Coating Strategy

A layered deposition approach is proposed to integrate both functionalities without compromising textile comfort:

4.1  Surface Structuring Layer: The textile is first modified to introduce nanoscale roughness using controlled deposition or etching techniques, followed by application of a low-surface-energy polymer to achieve superhydrophobic behaviour.

4.2  Photocatalytic Nanocoating Layer: A thin, uniform photocatalyst layer (TiO₂ or g-C₃N₄ nanoparticles) is subsequently deposited onto the structured surface. The coating thickness is carefully controlled to preserve air permeability while ensuring sufficient photocatalytic activity.

This sequential approach allows independent tuning of repellency and photocatalytic performance.

5. Performance Evaluation Methods

To assess the multifunctional performance of the hybrid-coated textiles, the following evaluations are proposed:

5.1  Water Contact Angle Measurement: Used to quantify surface repellency and confirm superhydrophobic behaviour.

5.2  Photocatalytic Antimicrobial Testing: Bacterial reduction tests and viral inactivation assays under controlled light exposure to evaluate active disinfection performance.

5.3  Wash Durability Assessment: Repeated laundering cycles followed by re-evaluation of repellency and antimicrobial activity to assess coating stability.

5.4  Breathability Testing: Air permeability measurements to determine the impact of coating layers on wearer comfort.

These metrics allow systematic evaluation of trade-offs between protection and usability.

6. Engineering Trade-Offs and Research Gaps

One of the central challenges in multifunctional textile coatings is the trade-off between surface functionality and comfort. While increased surface roughness enhances hydrophobicity, it may also stiffen the fabric or reduce air flow. Similarly, higher photocatalyst loading improves antimicrobial activity but risks pore blockage and reduced softness. Current literature often reports individual functionalities in isolation, with limited quantitative comparison of these competing effects. There is a clear need for integrated studies that examine repellency, antimicrobial efficiency, durability, and breathability together, rather than as separate performance indicators.

7. Novelty and Significance

The novelty of this approach lies in the simultaneous integration of passive fluid repellency and active photocatalytic disinfection within a single textile system. Unlike conventional antimicrobial finishes, which act only after contamination occurs, the hybrid strategy minimises contamination while addressing residual risk. Furthermore, focusing on engineering trade-offs rather than peak performance values provides practical insight into real-world applicability. Such multifunctional coatings have potential applications in medical textiles, protective clothing, public seating fabrics, and reusable masks. (Fig. 3)

Figure 3: Passive fluid repellency and active photocatalytic disinfection

8. Conclusion

Multifunctional hybrid coatings combining superhydrophobic and photocatalytic properties represent a promising direction for advanced antiviral and antibacterial textiles. By reducing pathogen deposition and actively inactivating remaining contaminants, these systems offer enhanced protection compared to single-function finishes. Future research should prioritise scalable coating techniques, durability under repeated washing, and systematic evaluation of comfort-related parameters. Addressing these challenges will be essential for translating hybrid textile coatings from laboratory concepts to commercially viable products.

9. References

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4. Perelshtein, I., et al. (2021). Hybrid antimicrobial coatings for textile materials. Materials Science & Engineering C, 123, 112004.

5. Zhang, L., et al. (2023). Visible-light-responsive photocatalysts for antimicrobial surfaces. Journal of Cleaner Production, 382, 135308.