Varvara Apostolopoulou Kalkavoura Post Doc

I come from Athens, the capital of Greece, and I am leaving in Stockholm since 2012. I am currently Postodoctoral Researcher at Stockholm University. During 2023 and 2024, I was visiting Researcher at  EMPA- Swiss Federal Laboratories for Materials Science and Technology. I have a PhD from Stockholm Univeristy (2021), a Diploma in Chemical Engineering (2011) from the National Technical University of Athens (NTUA) and a M.Sc. in Sustainable Technology (2014) from the Royal Institute of Technology (KTH).

I speak fluently Greek, English and Swedish and I worked in Hellenic Petroleum S.A. (2010) as a trainee, in SYchem (2011-2012) -a water purification company in Greece- and IVL- Hammarby Sjöstad (2014-2015) before starting the PhD at SU.

During my PhD, I worked with processing and characterization of cellulose nanomaterial-based foams for thermal insulation and thermal management applications. I focused on the thermal conductivity measurements under varying climatic conditions. One of my major findings was that the hygroscopic character of cellulose nanomaterials can be beneficial for their thermal conductivity behavior due to the competing mechanism between the swelling and the replacement of air in the pores with water. Phonon scattering at the multiple interfaces was mainly responsible for reducing the thermal conductivity of nanocellulose foams even below the superinsulating level. 

Since the beginning of my postdoc, I have shifted my focus on upcycling of textile waste into functional materials. I am focusing on the processing of blended fabrics and mainly the ones composed of cotton and PET. The projects I am involved are multiscale including the preparation of cellulose nanomaterials from cotton or cotton-blends and the upcycling and processing of inseparable polycotton into new high-performance materials. The main applications of the upcycled cotton and polycotton are thermal insulation and water purification. At the same time, the upcycled polycotton was used for the preparation of thermoplastic materials such as 3D printing filaments, commodity products and injection moulded accessories. My work on the upcycled textiles into thermoplastic materials has been also part of an international patent.

Despite my research activities, I have been also involved in teaching and supervision of master and PhD students. I have also experience with administrative and organisational activities within research as I also served as coordinator of Stockholm University Center for Circular and Sustainable Systems (SUCCeSS) and secretetary of SUCCeSS board. Furthermore, I have been presenting my research or the activities of SUCCeSS in wide and varying audiences.