Structural Organization And Thermal Properties Of Polycaprolactone (Pcl) Nanofibers And Energetic Ionic Liquids (Eils) Investigated By Flash Differential Scanning Calorimetry (Flash Dsc)

Author

Aishorjo Paul Bablee, Prairie View A&M University

Date of Award

8-2025

Document Type

Thesis

Degree Name

Master of Science

Degree Discipline

Chemical Engineering

Abstract

This study explored the thermal behavior and structural organization of two materials, electrospun poly(e-caprolactone) (PCL) nanofibers and energetic ionic liquids (EILs). To this purpose, Flash Differential Scanning Calorimetry (DSC) has been used. Both materials are of significant interest for advanced applications such as biomedical devices, drug delivery, propellants, and energy storage due to their tunable physical properties and responsive thermal behavior.

The first part of the study investigated the structure-property relationship of electrospun PCL nanofibers, a biodegradable, semi-crystalline polymer widely used in biomedical applications. Cooling rates ranging from 0.1 to 2000 K/s and a fixed heating rate of 500 K/s were employed to understand the influence of thermal history on crystallization, glass transition, cold crystallization, and melting behaviors. Results indicated that lower cooling rates promoted crystallinity with negligible amorphous content, while higher cooling rates suppressed crystallization, increased amorphous regions, and induced pronounced cold crystallization upon reheating. A notable reduction in glass transition temperature (Tg) with increasing cooling rates was observed, reflecting enhanced chain mobility under nanoconfinement. A critical cooling threshold (~100 K/s) was identified, beyond which crystallinity sharply declines. These findings provide insight into tailoring the thermal properties of PCL nanofibers for applications such as drug delivery, tissue engineering, and biodegradable implants.

The second part of the study investigated the glass transition temperature of energetic ionic liquids containing imidazolium and pyridinium groups paired with dicyanamide anions. Using the Mettler Toledo Flash DSC 2+, the limiting fictive temperature (T'f), equivalent to Tg, was measured versus cooling rate. Results show there was a difference between T’f and Tg due to the energetic ionic liquids’ molecular complexity. These findings help elucidate the fundamental structure–property–performance correlations within ILs, providing predictive insights into the thermophysical behavior and stability of these compounds. Furthermore, these results contribute to a foundational understanding necessary for optimizing processing strategies and material selection for ILs and related materials such as deep eutectic solvents. Collectively, this research demonstrated the versatility of Flash DSC in capturing rapid thermal transitions in both polymeric and ionic materials, enabling precise control over their structural organization and thermal properties for emerging applications.

Index Terms: Cold crystallization, flash DSC, glass transition.

Committee Chair/Advisor

Nabila Shamim

Committee Member

Irvin W. Osborne-Lee

Committee Member

Kazeem Olanrewaju

Committee Member

Ziaul Huque

Publisher

Prairie View A&M University

Rights

Date of Digitization

10/09/2025

Contributing Institution

J. B . Coleman Library

City of Publication

Prairie View

MIME Type

Application/PDF

Recommended Citation

Bablee, A. P. (2025). Structural Organization And Thermal Properties Of Polycaprolactone (Pcl) Nanofibers And Energetic Ionic Liquids (Eils) Investigated By Flash Differential Scanning Calorimetry (Flash Dsc). Retrieved from https://digitalcommons.pvamu.edu/pvamu-theses/1619