**1. Introduction**

In the field of intelligent packaging, the use of electrically conductive polymer-based materials opens up new opportunities to create "smart" labels or tags. Intelligent or smart packaging is the umbrella term for a range of intelligent technologies that allow packaging to contain, evaluate, and transmit relevant information [1]. For instance, smart packages can enable monitoring of the conditions and quality of the packaged products (e.g., food freshness) from the production line to the end user. This includes relevant information and spoilage indicators such as time, temperature, and pH or the presence of different gases, chemical contaminants, pathogens, etc. Apart from this, smart labels can also include components that range from bar codes to radio frequency transmitters, i.e., radio frequency identification (RFID) devices and printed electronics [2]. The smart tags can be used to electronically transfer information from the packaging to the consumer about the packaged material through, for instance, refrigerator displays. Therefore, intelligent packaging systems can make packaging more informative and interactive whereas their global demand is expected to grow strongly to reach US \$1.5 billion by 2025 [2].

Currently, however, the intelligent packaging technology habitually requires the use of a silicon chip as the substrate for the high-frequency electronics, limiting its application for packaging uses. In addition, there is an increasing necessity for the development of new thin-film transmitters that can be efficiently embedded in the packaging structure. In this sense, the use of poly(ethylene-*co*-vinyl alcohol) (EVOH) copolymers could represent an advantageous strategy since this family of copolymers is frequently employed in high-barrier packaging films in the form of inner layers with very low thickness (typically well below 10 μm). In addition, EVOH films are highly transparent and hydrophilic, ye<sup>t</sup> water-insoluble. Therefore, EVOH is a suitable candidate to be efficiently employed for the inclusion of smart tags in the packaging structure and/or for the creation of patterns acting like a bar code. This would provide a unique response to electrical stimuli that give relevant information about the physicochemical properties of the foodstuff packaged and/or for traceability and improved supply chain managemen<sup>t</sup> (SCM) purposes.

Graphene was the last carbon allotrope to be discovered, after fullerenes and carbon nanotubes (CNTs) [3]. This carbonaceous material is presented in the form of a unique two-dimensional (2D) macromolecular sheet of carbon atoms with a honeycomb-like structure, the so-called graphene nanoplatelets (GNPs), which has become one of the most promising materials available today. Compared to other nano-sized carbonaceous systems (e.g., CNTs), GNPs have attracted considerable attention because of their combination of outstanding mechanical flexibility, excellent electrical and thermal conductivity, optical transparency, and low density. The peculiar properties of single layers of graphene include a Young's modulus of ~1 TPa, an electrical conductivity (σ) of approximately 6000 S/cm, a thermal conductivity (λ) of up to 5300 W/m·k, a surface area of over 2600 m2/g, a high chemical tolerance, and a broad electrochemical window [4,5]. As a result, GNPs have been widely considered as a perfect filler to develop novel carbon-based reinforced polymer nanocomposites with enhanced thermal, electrical, and mechanical properties [6,7]. In this sense, the use of GNPs-containing plastics is very advantageous for several applications in energy and electronics, but their use can also be originally focused on intelligent packaging strategies in combination to EVOH since it is a food contact polymer with excellent optical properties and polarity.

Electrohydrodynamic processing (EHDP) is a straightforward, versatile, and low-cost technique based on the application of high electrical fields to a viscoelastic polymer solution or melt via a metallic capillary orifice that allows to fabricate polymer nanostructures with different functionalities [8]. EHDP is habitually referred to as electrospinning when fiber-based morphologies are produced in which a wide range of polymers and biopolymers can be processed. Electrospun nanofibers can find several applications in the packaging industry, including the development of active and intelligent systems [9,10]. Although the electrospun materials are predominantly polymer based, certain amount of non-polymer contents (e.g., nano-sized fillers) can also be incorporated into the primary electrospinning solution to form hybrid ultrathin or nanocomposite fibers [11–13]. At present, the incorporation of GNPs has been achieved into electrospun fibers of poly(vinylpyrrolidone) (PVP) as a conductive additive to enhance the high-rate capabilities for lithium-ion batteries [4], polystyrene (PS) and polyvinyl chloride (PVC) to generate superhydrophobic surfaces [14], poly(vinyl acetate) (PVAC) to improve the optical absorption for ultrafast photonics [15], polyacrylonitrile (PAN) to produce carbon nanofibers (CNFs) [16], polyaniline/poly(methyl methacrylate) (PANi/PMMA) blends for conductive devices [17], and PAN/PVP blends as high capacitance materials [18].

In this work, for the first time, EVOH/GNPs nanofibers were prepared by electrospinning. The morphology, thermal properties, and electrical conductivity of the resultant hybrid nanofibers mats were characterized. Finally, the electrospun mats were subjected to a thermal post-treatment in order to generate films that could be applied for creating smart labels or tags with high electrical rate capabilities in the field of intelligent food packaging.
