Solubility and adhesion characteristics of plasma polymerized thin films derived from Lavandula angustifolia essential oil

Abstract

in Wiley InterScience (www.interscience.wiley.com).ABSTRACT: Integration and implementation of organic polymer thin films often require knowledge of the stability when in contact with solvents and the adhesion quality when applied to different substrates. This article describes the solubility and adhesion characteristics of organic polymer thin films produced from Lavandula angustifolia essential oil, using radio frequency plasma polymerization at four RF power levels. Contact angle data was obtained for various solvents and used to determine the surface tension values for the polymer by using three established methods. A relatively strong electrondonor component and a negligible electronic acceptor component for the polymers indicate that they are monopolar in nature. Solubility data derived from interfacial tension values suggest that the polymers would resist solubilization from the solvents explored. The strongest solvophobic response was assigned to water, whereas diiodomethane demonstrated the weakest solvophobic response, with DG 121 > 0 in some instances depending on the surface tension values used. The adhesion tests of the polymers deposited on glass, PET, and PS indicated that the adhesion quality of the thin film improved with RF power, and it was associated with an improvement in interfacial bonding.

Wetting, Solubility and Chemical Characteristics of Plasma-Polymerized 1-Isopropyl-4-Methyl-1,4-Cyclohexadiene Thin Films

“…The values are also consistent with those reported for plasma thin films deposited from other secondary plant metabolites, where total SFTs of 45-48, 36-40 and 31-37 mJ·m −2 were found for thin films derived from linalyl acetate [68], Lavandula angustifolia essential oil [7] and terpinen-4-ol [69], respectively.…”

“…While this rate of change was considered insignificant, the positive ramp suggested the occurrence of the reorientation of functionalities at the interface. For the DIM data, all of the films were stable with time, and the highest CA was found for films fabricated at 75 W. These results indicate that pp-GT is more stable as the RF power is increased, due to an increase in the degree of cross-link density associated with these deposition conditions [7].…”

“…On the other hand, Neumann's approach derives the SFT from a purely thermodynamic point of view and, therefore, neglects the molecular origins of SFT [7]. However, this is the only theory that allows the calculations to be done by using just one probing liquid.…”

“…The motivation for using organic materials stems from their chemical versatility, low cost, low temperature fabrication and ability for reel-to-reel printing, as well as mechanical flexibility [1]. The attractive synthetic and processing flexibility of organic materials allows for fine tuning of their properties to achieve a desired combination of optoelectronic, physicochemical, mechanical and biological characteristics, and controlling the manner in which these materials interact with relevant liquids [7]. The latter is an important aspect for optoelectronics and biomedical applications alike.…”

“…Contact angle (CA) analysis is typically used to obtain primary data from which the degree of wettability for a specific solid-liquid combination can be inferred [7,11], with lower CAs indicating better wetting compared to larger CAs. This analysis also provides indirect information about the structure of the film matrix, where observed changes to θ at the liquid/solid interface are attributed to specific solid-liquid interaction mechanisms, such as absorption, spreading and swelling [12].…”