## 1 Introduction  
Since the publication of the first scientific work on nanocellulose-based films [1], cellulose nanofibrils (CNFs) have attracted the attention of researchers worldwide. Nanocellulose possesses excellent physicochemical properties and is derived from the most abundant natural polymer on Earth. Moreover, it is both renewable and biodegradable, making it an environmentally friendly material [2]. Nanocellulose can be obtained from various sources rich in cellulose, such as wood pulps (sulfate or sulfite), agricultural residues and marine biomass. Usually, production involves a chemical pre-treatment step, such as acid hydrolysis, oxidation or enzymatic treatment, followed by an intensive mechanical process, such as homogenization, grinding or ultrasonication, which promotes the fibrillation of cellulose fibers. Nanocellulose can be obtained in distinct forms, such as gel or colloidal suspension, depending on the concentration and degree of dispersion of the fibrils [3]. In the present work, the nanocelluloses were obtained from bleached eucalyptus pulp, produced by two distinct chemical processes, sulfite and sulfate. The sulfate process uses an alkaline solution of sodium hydroxide (NaOH) and sodium sulfide (Na\({}_{2}\)S). The sulfite process involves an acidic solution containing bisulfite (HSO\({}_{3}\)\({}^{-}\)) and magnesium cation (Mg\({}^{2+}\)). Subsequently, both pulps were subjected to an oxidative TEMPO process, followed by identical mechanical treatment in the homogenizer. From the nanocellulose gels, it is possible to produce films with high transparency and high mechanical resistance [4; 5]. Despite these excellent attributes, required in a wide range of applications such as sustainable packaging, electronic devices, medicinal applications, membranes, among others, the performance of CNF-based films is still inferior to synthetic plastic concerning water sensitivity. Knowledge gaps still exist, especially for food packaging applications [6]. This weakness seriously limits the practical use of this biopolymer in a wide range of food packaging. However, these films can provide an alternative to plastic regarding biodegradability and waste reduction [7]. Nanocellulose itself has a hydrophilic nature due to the presence of hydroxyl groups (-OH) on its surface presenting limitations in applications that require resistance to humidity. This drawback can be changed using chemical/physical modifications of nanocellulose [8]. Research in this area continues to foster the development of eco-friendly materials that meet industry requirements [7]. Hydrophobization techniques, such as the application of a hydrophobic layer of calcium carbonate modified with stearic acid on CNF films, has shown promising improvements in creating effective moisture resistance [9]. The layer-by-layer (LbL) technique allows the application of ultra-thin coats of hydrophobic polymers, like waxes, promoting effective water resistance [10]. In this work, a LbL assembly using natural components, including carnauba wax particles, demonstrated to produce hydrophobic coatings on CNF films. These methods allow for moisture barriers without significantly increasing thickness. Also, it was previously demonstrated that wax coatings could be a way to increase the moisture resistance of nanocellulose films and improve their hydrophobicity [11]. A strategy that seems to overcome one of the greatest weaknesses of CNF films, its hydrophilicity, seems to be the combination of nanocellulose with hydrophobic products such as natural waxes. Natural waxes are lipids, whose chemical composition presents a mixture of hydrocarbons, free fatty acids, fatty alcohols, esters, ketones and sterols. A good understanding of the chemical composition is of the highest importance since wax can vary depending on its origin and extraction methods [12]. The use of bio-based waxes and synthetic hydrophobic polymers is important in this context, as they achieve hydrophobicity without sacrificing biodegradability.