Empa’s Laboratory of Biomimetic Membranes and Textiles is offering a
Our laboratory. Empa’s Laboratory of Biomimetic Membranes and Textilesaims to develop materials and systems for the protection of the human body and its health. The products developed in collaboration with industry are used in the fields of occupational safety, sport, medical applications and health-tech.
Background. The principle behind electrohydrodynamic (EHD) drying is that airflow is generated by means of corona discharge, so-called ionic wind. This ionic wind enhances heat and mass transfer from any wet material that is placed in this airflow field. As electrohydrodynamic drying is a non-thermal technology, it is particularly attractive to dehydrate soft, heat-sensitive products, such as several foods. Compared to conventional convective drying, EHD drying has been reported to reduce drying time, reduce product shrinkage, increase rehydration capacity, improve (soften) texture, and preserve color and flavor better. It is also found to preserve better the nutritional content (vitamins). Several of the physical processes that occur in electrohydrodynamic drying are also relevant for electrospinning processes. This technology is used at our lab to spin micro- and nano-fibrous, functionalized membranes for tissue engineering and drug delivery.
Objective.The first aim is to increase our insight in the EHD drying process and the electrospinning process via multiphysics modelling of the electrostatics, the ion flow, the resulting EHD-generated airflow and, finally, the material drying process. This mechanistic modeling approach should complement the current experimentally-based knowledge. The second aim of this project is to design, build and optimize an advanced, lab-scale experimental setup for electrohydrodynamic analysis of drying of soft materials. With this unique experimental setup, we aim to better quantify the contribution of the different drivers behind the drying process.
Administration. A project duration of 3 years is envisaged to carry out the above research tasks in the form of a PhD thesis. The project is supported by Empa under the supervision of Thijs Defraeye, but involves a joint affiliation with a Swiss federal or cantonal university. The candidate will perform his research at Empa in St. Gallen. Desired starting date is 1st of July 2019 or upon mutual agreement.