# Sprayed Graphene-Based Coating Enabling Antifog and Smart Features

## TL;DR

This paper introduces a graphene-based coating that offers antifog, electrical, and thermal properties, suitable for use on recyclable plastics in various industries.

## Contribution

The novelty lies in combining antifog, electrical conductivity, and thermal functionality in a graphene-based coating for recyclable plastics.

## Key findings

- Spray-coated graphene films on polyethylene showed a 1.5-fold reduction in contact angle with higher optical transmittance.
- The coating improved Young’s modulus by 1.8-fold compared to bare polyethylene.
- The graphene/PEDOT:PSS multilayer coating increased thermal conductivity by 283% compared to polyethylene.

## Abstract

Large-area and low-cost
coatings introducing electrical, optical,
thermal, and surface control functionalities are highly demanded in
the fields of flexible and wearable electronics for applications ranging
from agrifood and smart packaging to electronic textiles and aerospace.
Here, we report a graphene-based coating with combined antifog, electrical,
and thermal functionalities suitable for spray deposition on commercially
recyclable plastic substrates. A graphene ink formulation in a low-boiling-point
solvent, stabilized by polyvinylpyrrolidone, enables compatibility
with deposition processes in the coating industry. Spray-coated graphene
films on polyethylene demonstrated antifog properties, achieving a
1.5-fold reduction in the contact angle at a 5% higher optical transmittance
compared to commercial antifog coatings. Mechanical testing revealed
more than a 1.8-fold improvement in Young’s modulus compared
to the bare polyethylene. Moreover, by depositing another thin film
of poly­(3,4-ethylenedioxythiophene)-poly­(styrenesulfonate) (PEDOT:PSS)
underneath the graphene coating, electrical conductivity (sheet resistance
of about 330 Ω/sq) with similar transparency can be achieved.
Testing of the thermal properties of the film demonstrated how these
conductive coatings can be used as heaters, reaching about 50 °C
at a 30 V bias. Moreover, the graphene smart antifog coating showed
a 97% improvement in thermal conductivity, increasing to 283% for
the graphene/PEDOT:PSS multilayer coating with respect to the PE.
The integration of these combined and novel smart functionalities
on commercial recyclable plastic widens the application arena of smart
coatings beyond agrifood, toward packaging, automotive, and aerospace
fields.