**1. Introduction**

Currently, bacterial growth is the main problem of air purification systems such as heaters, air-conditioning and ventilators that are used indoors [1,2]. Some microorganisms are adhered to and absorbed by the parts of the air purifying systems which return to the environment under operational conditions, spreading pathogenic bacteria not only to humans but also to plants and animals [3]. Among the bacteria that are found in the environment and are scattered by air purifying equipment are *Escherichia coli*, *Bacillus subtilis*, *Staphylococcus aureus* and others such as *Serratia marcescens* that cause diseases such as gastroenteritis, urinary tract infections, meningitis and brain abscesses, in addition to pathogenic bacteria that also affect plants and cause cell death such as *Bacillus licheniformis* [4,5]. The alternative to this problem for a long time, has been the combination of air-purifying equipment

filters with nanocoatings that inhibit bacterial growth, using various polymeric materials such as polyimide, polyurethane, polyacrylonitrile and polysulfone, which has generated contamination and low resistance to exposure of the various environmental effects [6,7]. For this reason, one of the polymers that promises to be efficient as a multifunctional material in the design of filters of air purification equipments is polyetheretherketone (PEEK). This semicrystalline thermoplastic polymer formed by an aromatic chain, combines ketone and ether functional groups between the aryl rings with a mechanical strength stable at high temperatures and resistance to most inorganic and organic substances in comparison with other polymers derived from the polyaryletherketone family (PAEK) [8–10]. These characteristics make PEEK an ideal material for various applications such as components in filters for air decontamination and as complements in decontaminating systems, using effective coatings based on silver nanoparticles with high activity in low concentrations [11–14]. In this sense, several methods have been used to functionalize the PEEK surface, among the most common being the sputtering and plasma deposition techniques [9,15,16]; however, deposition by means chemical routes have attracted great interest due to its simplicity and low cost [17]. Among chemical methods, the deposition of silver nanoparticles using the Tollens reagent has been studied for its simplicity, fast deposition and control of nanoparticle size, the use of non-toxic reagents being one of the most clear benefit of this procedure [18]. This green method allows a silver surface formed by homogeneously distributed nanoparticles in the substrate to be obtained, where the reduction of the ammoniacal silver complex takes place when a monosaccharide as glucose is used as a reducing agent. This results in high antibacterial effectiveness due to the development of small silver (Ag) particle sizes [19,20].

Under the above considerations, the present study aims to obtain polyetheretherketone films coated with various concentrations of silver by a simple chemical reduction method, which contributes to the development of deposition methodologies of silver nanoparticles in polymeric substrates, without the need to use expensive equipment and avoiding the use of polluting reagents. In the same way, the synthesis method using diamonical complexes of silver and glucose as a green reducing agent has the advantage of controlling the size and distribution of the AgNPs coated in the PEEK polymer, favoring antibacterial activity against *E. coli*, *S. marcescens* and *Bacillus licheniformis* for potential biomedical applications.

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