Fabrication and characterization of a novel terpolyester film: An alternative substrate polymer for flexible electronic devices

Designing and development of flexible electronic devices require a detailed investigation of the substrate materials available for the fabrication of the devices. This research work reports the fabrication of a novel film with a copolyester of high trans-1,4-cyclohexandimethanol, terephthalic acid, and naphthalene dicarboxylic acid (PCTN) using melt extrusion. The synthesized amorphous film was uniaxially stretched and thoroughly characterized for their mechanical, thermal, thermo-mechanical, water barrier, and optical (birefringence) properties. Universal testing machine (UTM) and differential scanning calorimetry (DSC) results showed that developed film was having good mechanical and thermal properties, with exceptional dimensional stability, which was confirmed by the thermo-mechanical analyzer (TMA). Results indicated that analyzed properties increase with the increase in the draw ratio (DR). This is due to the increase in the orientation polymeric chains inside the films which were verified by DSC and X-ray diffraction (XRD). Additionally, PCTN film has lower water barrier and birefringence properties compared to conventional polymers such as poly (ethylene terephthalate) (PET), poly (ethylene 2,6-naphthalate) (PEN), and polyimide (PI) films. Based on the exceptional performance properties, novel PCTN film may find a strong position as a substrate for next-generation flexible electronics among various performance materials.