Fibers are valuable to biomedical applications. Used as sutures or meshes, there is an increased dual need to provide functionality such as drug delivery. Porosity represents a high surface area to volume architecture. Coaxial fibers with porous and non-porous layers offer a new design framework for fiber design that can resolve dual needs of mechanical robustness with transport phenomena. Using preferential solubility of a polymer in supercritical CO2, we develop a new architecture using biocompatible polymers based on porous core-sheath fiber fabrication technique. Polycaprolactone was selected as the CO2 miscible phase and Poly(butyrate adipate terephthalate)(PBAT) as the immiscible phase. The mechanical performance of the fibers was investigated using quasi static and dynamic loading. SEM images indicate no physical detachment of the two polymer surface after CO2 exposure indicating a successful amalgamation of polymers at the boundary of core and sheath. PCL as a sheath and as a core showed an increase of 650% and 468% in tensile strength compared to pristine PCL and PBAT. Introduction of porosity on the surface of coaxial fiber fPCL(cPBAT) further enhanced the yield strength increases by 40%. Dynamic mechanical analysis was used to analyze the viscoelastic properties of the fibers. The storage and loss modulusmore »
MULTI-SCALE COMPUTATIONAL FRAMEWORKS FOR HIERACHICAL POROUS MATERIAL DESIGN
By virtue of their extensive potential in energy conversion and storage, catalysis, photocatalysis, adsorption, separation and life science applications, significant interest has been devoted to the design and synthesis of hierarchical porous materials. The main factors which determines the performance of hierarchical porous materials for an application include structure (pore size, porosity, tortuosity), materials (scaffold, dopants) and operating conditions. Traditionally, these hierarchical porous materials are synthesised and fabricated through a manual trial and error procedure, which is an expensive and time-consuming approach. However, there have been significant advances in mathematical, computational and engineering tools toward solving and optimising multiscale descriptions of physical phenomena. This motivates a computational-aided framework to tailor the fabrication of hierarchical porous materials to be optimised in performance for their specific application. In this work, a reactive-transport system in porous media is modelled using computational fluid dynamics. While microscale descriptions are too computationally expensive and macroscale models fail to accurately describe a physical phenomena in specific parts of computational domains, hybrid - or multiscale - algorithms, are used. Using the information provided by the numerical simulation, multiscale model-based design of experiments are developed to optimise the material’s performance on their particular usage. It is proposed that hierarchical more »
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