Bilayer Films Of Poly(Epsilon-Caprolactone) Electrosprayed With Gum Rosin Microspheres: Processing And Characterization

Bilayer systems, consisting of electrosprayed gum rosin microspheres (eGR) and poly(epsilon-caprolactone) (PCL), were prepared. First, the electrospraying processing conditions of GR in two different solvents, dichloromethane, and chloroform, were optimized. Various electrospraying polymeric solution flow rates and applied voltages were tested and morphologically analyzed in terms of particle size distribution and microspheres density. The conditions at which a homogeneous and narrow microspheres size distribution was achieved were chosen as the best for each solvent. The eGR was deposited onto a compression-molded PCL film to obtain the bilayer systems. The bilayer systems were characterized by their visual appearance, microstructural analyses, thermal and mechanical performance, and surface wettability. It was determined that the mechanical and thermal behavior of PCL film was not affected due to the addition of the eGR microspheres layer. Meanwhile, the eGR layer considerably changes the surface color of the PCL film, reduces the film transparency, and produces a blocking effect in the UVB region and high blockage in the UVA region. In addition, the microspheres layer presents a tunable hydrophobicity depending on the solvent used, reaching values of ultrahydrophobic surfaces. Thus, the obtained result reveals a great potential to easily process bilayer systems with high interest in sustainable agricultural, packaging, and/or biomedical applications.