A novel interferometry-based method to study the anisotropy and kinetics of liquid to solid transition in polymer

[Display omitted] •Twin-Interferometry is used first time to study the kinetics of curing polymer.•Extraction of optical path length variation embedded as fringe shift is demonstrated.•Kinetic parameters of curing polymer are extracted first time by twin-interferometry.•Variation of Kinetic parameters in orthogonal directions are extracted first time.•Obtained kinetic parameters are validated by multiple standard techniques. We propose and demonstrate a first Twin -interferometry based optical approach for studying and exploring anisotropy and directional dependent crystallization kinetic of curing polymers under isothermal condition. A commercial polymeric solution of polyvinylidene fluoride hexa-fluoropropylene (PVDF-HFP) with five different concentrations were prepared and utilised for this study. A Twin-interferometer (TIM) is designed to record the rate of shift in Michelson’s fringes caused by rate of change of optical path length of a transparent polymeric solution in two orthogonal directions during curing. Pair of interferogram referred as Twin- interferogram (TIG) is recorded for the sample of all concentration during its liquid to solid transition. An extraction approach for various crystallization parameters such as anisotropy, crystallization half-life time, constants governing the rate and dimensionality of crystallization, and their variation along distinct direction from TIM is demonstrated. The results provided by TIM are verified by a method of anisotropy annihilation and other experimental techniques includes Scanning electron microscopic (SEM), Polarising optical microscopic (POM) and Dielectric spectroscopic studies.