Year: 2025
Type: article
Abstract: This paper reports the details of percent crystallization, degree of crystallization, and order parameters of 4-oxo 4'-cyano-biphenyl (8OCB) Liquid Crystal (LC) during crystallization transitions that occur when heated and cooled at various ramp rates. It is found that 8OCB exhibits dynamic behavior during its crystallization transition. The Differential Scanning Calorimetry (DSC) technique was used to determine the heat flow of 8OCB as a function of temperature at three ramp rates: 5 °C/min, 10 °C/min, and 20°C/min. Heating was performed from -40 °C to 100 °C, followed by cooling from 100 °C to -40 °C. LoggerPro was then used for further data analysis of the DSC data to identify dynamics in its crystallization. As 8OCB was heated and cooled, the crystallization phase, both in heating and cooling, showed changes in its degree of crystallization, order parameters, and percent crystallinity. There were also noticeable movements and degradation of the crystallization phase transitions as the ramp rate increased. It was found that the number of sub-peaks that appeared during crystallization changed for both heating and cooling. The degree of crystallization decreased with heating and increased during cooling for increased ramp rates. Furthermore, the study of order parameters supports the dynamic behavior of crystallization, with a lower-order parameter for heating crystallization and a higher-order parameter for cooling crystallization. This further complicates cooling crystallization. This further supports the phenomenon where LC molecules do not completely return to a completely ordered state when cooled and retain some energy within the molecules before reheating. However, the stability of nOCB during these temperature changes retains a high degree of crystallinity throughout, providing valuable insight into the practical application of 8OCB in the Liquid Crystal (LC) world.
Authors: Grace Petrarca, Dipti Sharma
Institution: Emmanuel College - Massachusetts
Language: English
Field: Materials Science
Domain: Physical Sciences
Open Access status: hybrid
Funder: Worcester Polytechnic Institute
OpenAlex ID: W4411242614