**1. Introduction**

In recent years, the incidence of viruses, bacteria, parasites and fungi has risen considerably, especially among immune-compromised patients, geriatric and pediatric [1]. The uncontrolled growth of infectious diseases, which are becoming harder to treat, is a silent threat with long-term consequences for global public health and economy [2]. The COVID-19 crisis has brought into sharp focus the impact of infectious diseases. There are vital lessons to learn from this pandemic. Now more than ever, we need to make robust and comprehensive investments into the way we prepare and respond to health emergencies. This has the potential to avoid into long-term, global health threats and economic crises. A major challenge facing textile industries is to enhance the production of protective textiles. Natural fibers such as cotton are sensitive to microorganisms attack since their structure is hydrophilic and porous, allowing the retention of oxygen, moisture and nutrients required for microorganism development.

**Citation:** Bouaziz, A.; Dridi, D.; Gargoubi, S.; Zouari, A.; Majdoub, H.; Boudokhane, C.; Bartegi, A. Study on the Grafting of Chitosan-Essential Oil Microcapsules onto Cellulosic Fibers to Obtain Bio Functional Material. *Coatings* **2021**, *11*, 637. https:// doi.org/10.3390/coatings11060637

Academic Editor: Philippe Evon

Received: 15 April 2021 Accepted: 21 May 2021 Published: 27 May 2021

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**Copyright:** © 2021 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

The healthcare sector consumes large amounts of textiles such as staff uniforms, patient clothing, operation room gowns and bed linen. Placing advanced properties and green criteria during production can increase the demand for antimicrobial finishing preventing microorganisms from adhering to the textile surface.

During the last decade, a number of antimicrobial textiles have been developed using techniques like the incorporation of antimicrobial agents into the synthetic fibers during extrusion, the surface grafting of active compounds or the fiber modification by physical or chemical treatments [3].

Several antimicrobial agents were imparted to textiles like triclosan, quaternary ammonium compounds, metal salts, polybiguanides and *N*-halamines [4].

However, the main disadvantage remains that these active components present drawbacks such as leaching of textiles during washing causing environmental problems and toxicity when exposed to sunlight such as for Triclosan, an efficient antimicrobial agen<sup>t</sup> that has been banned by many countries [4].

Textile antimicrobial finishing needs to be effective against microorganisms, but the more important issue is the increasing demand of non-toxicity to the environment and the user [5]. Therefore, medical textile industries need to use new active agents that are safe and which present a broad spectrum of activity to ensure the control of microbes' multiplicity. In addition, optimum efficiency must be reached while providing the properties of textiles.

Recently, essential oils have been emerging as effective antimicrobial agents [6]. They are highly concentrated substances extracted from plant organs such as flowers, leaves, bark and seeds [7].

They contain various aromatic compounds [8]. These natural products have the advantage of providing a broad spectrum of biological activities [9]. This property makes them promising active agents to fight against the spread of multi-resistant microorganisms, which is one of the greatest challenges medical textile industries need to face.

Despite their antimicrobial activity, essential oils are not widely exploited in the textile sector since they do not dissolve in water [10]. To overcome this problem, Chitosan could be used to encapsulate these active compounds [11]. The target of the present work is to achieve cinnamon oil encapsulation using Chitosan and to graft the obtained microcapsules onto the cellulosic fiber's surface. The physio-chemical characteristics and antibacterial activity of finished samples were investigated.

#### **2. Materials and Methods**
