The RecyWax+ project, supported by the Dutch Research Council NWO OTP programme, is offering a PhD position focused on the multiscale modelling of recycled wax for sustainable thermal storage. The project aims to develop efficient and low-cost heat storage solutions using organic phase change materials (PCMs), which are crucial for reducing the carbon footprint of heating in buildings. The research combines advanced multi-physics modelling with experimental validation to design and optimize PCM composites. The core innovation lies in utilizing waxes derived from the pyrolysis of plastic waste streams, combined with ultra-conductive graphene networks, to create compact and efficient thermal energy storage systems. These systems exploit phase transitions to store and release heat, functioning as 'heat batteries.' The PhD candidate will employ molecular modelling techniques to address several key challenges: characterizing the molecular structure and distribution of polymer pyrolysis waste streams, modelling filler-matrix interfaces using Gromacs and LAMMPS (with MARTINI-like upscaling), optimizing thermal transport through nanofiller surface functionalization, and simulating ideal filler-filler and filler-matrix interface structures. The research will bridge atomistic properties with macroscopic network behavior, aiming to predict and enhance the thermal conductivity of PCM composites. The project is led by Professors Alexey Lyulin, Heiner Friedrich, and Henk Huinink from Eindhoven University of Technology (TU/e), and Professor Bernard Geurts from the University of Twente. The successful candidate will join a multidisciplinary team working at the intersection of materials science, chemistry, and engineering, with a strong emphasis on sustainability and upcycling of waste materials. The position offers a unique opportunity to contribute to next-generation energy storage solutions and to develop expertise in molecular dynamics, composite materials, and sustainable technologies.