Electrical behavior of PET films coated with nanostructured organic–inorganic hybrids

Abstract

Hybrid coatings, based on poly(ethylene oxide) (PEO) or polycaprolactone (PCL) and silica (SiO 2 ), at different organic-inorganic compositions have been used to coat PET films employed in the electric industry to produce capacitors. The overall electrical behavior of the coated films has been investigated. The electrical strength of the coated films increases up to 10-15% of the uncoated ones regardless of polymer type (PEO/PCL) and amount of inorganic phase, as far as the thickness of the coating is below 5 mm. A systematic increase of surface electrical conductivity is found in all coated samples which however still behave as insulators. Permittivity and loss factor also increase particularly at low frequencies (< 10 Hz) on account of the presence of ions deriving from the sol-gel process and on the presence of interfacial polarization probably related to the coatings nanostructurated morphology which leads to phase separation.

Polymer/Silica Nanocomposites: Preparation, Characterization, Properties, and Applications

“…There are many different synthetic techniques used in the sol−gel process to generate polymer/silica hybrid materials, two approaches are normally utilized, as indicated in Scheme : (i) In situ formation of an inorganic network in the presence of a preformed organic polymer. – To obtain optically transparent materials, conditions need to be identified under which phase separation will not occur during both the gel forming and the drying processes. Introduction of covalent bonds between the inorganic and organic phases is common to reduce phase separation.…”

Graphene and its nanostructure derivatives for use in bone tissue engineering: Recent advances

“…These materials are also known as phase‐interconnected organic–inorganic nanocomposites because of the high level of interconnection between the two phases with domain size approaching the nanometer scale, which are the basis of their optical transparency and high toughness. These sol–gel organic–inorganic hybrids have been successfully used for the preparation of tough, transparent, flexible coatings for both plastic and glass‐ceramic substrates, and were demonstrated to be highly adherent and resistant to wear and abrasion . Moreover, the solution chemical process for their preparation easily allows the inclusion of functional objects or molecules inside their formulation.…”

“…These sol-gel organic-inorganic hybrids have been successfully used for the preparation of tough, transparent, flexible coatings for both plastic and glassceramic substrates, and were demonstrated to be highly adherent and resistant to wear and abrasion. [59][60][61][62] Moreover, the solution chemical process for their preparation easily allows the inclusion of functional objects or molecules inside their formulation. In particular, sol-gel hybridswith poly(ethylene glycol) (PEG) domains covalently bonded to a silica network are very flexible and resistant 63 and are particularly suited for the coating of biomedical devices and implants because of their medical safety and biocompatibility.…”

Characterization and thermal‐oxidative degradation behavior of poly(ethylene terephthalate‐co‐4,4′‐bibenzoate) prepared via direct esterification technique

“…When nanometer silica was incorporated in PET, it could serve as a barrier to both water and oxygen, thus the resulting film may delay the degradation in heating process [2]. An alternative route is the deposition of nanostructured organic–inorganic hybrid coatings on PET films [4, 5]. Marini et al prepared polyethylene glycol/silica and polyvinyl alcohol/silica hybrid sol–gel solutions in advance, and then these sol–gel solutions were used to coat both sides of PET films.…”

“…Marini et al prepared polyethylene glycol/silica and polyvinyl alcohol/silica hybrid sol–gel solutions in advance, and then these sol–gel solutions were used to coat both sides of PET films. Only slightly beneficial effect on the PET electrical performance was observed [4]. A thermo‐tropic liquid crystal polyester (TLCP) was also used as a blend component to increase the thermal‐oxidative resistance of PET, but the addition of 10 and 20 wt% of TLCP only increased 1–2°C of the initial thermal decomposition temperature ( T onset ) and the 2–3°C of the maximum thermal decomposition temperature ( T max ) [6].…”