Coarse-Grained Simulation of Heat Transport in Functionalized Nanotubes for Biomedical Applications

Abstract

This thesis presents the development of a mesoscopic simulation framework usingenergy-conserving Dissipative Particle Dynamics (eDPD) to investigate thermal transport phenomena at the interface between carbon nanotubes (CNTs) and biological materials in aqueous environments. We introduce a novel method for including Kapitza in resistance by tuning repulsion and heat exchange parameters within the eDPD framework, enabling accurate modeling of interfacial heat transfer between single-walled carbon nanotubes (SWCNTs) and water. In developing this method, we resolve some discrepancies in the eDPD algorithm as currently described in the literature. We observed that thermal boundary resistance at a liquid interface can be increased by as much as ∼ 40% by increasing the interfacial repulsion. Furthermore, thermal rectification can be modeled by introducing asymmetry in the interfacial parameters, demonstrating that heat conduction through a carbon–fluid interface becomes direction-dependent under certain functionalization or temperature gradient conditions. This insight provides a foundation for designing the surfrace properties of materials with directional heat transport capabilities, which are relevant for thermal management and biomedical control. We provide a systematic approach for selecting DPD parameters that reproduce realistic thermal and mechanical properties of carbon nanotubes and surrounding x media. We applied our coarse-grained model to study the adsorption behavior of DSPE-PEG amphiphilic molecules near CNTs. By varying temperature and concentration, one can examine how these factors affect protein-like molecular anchoring to the CNT surface. Our model captures essential features of polymer–nanotube interactions, including the number and spatial configuration of anchored molecules. Simulations indicate a competition between DSPE-PEG agglomeration and DSPE-PEG/CNT binding. We find that the binding of amphiphilic molecules to CNTs is not degraded by transient heating of CNTs, suggesting that pulsed radiation can be used in photothermal therapy.