PhD opening: 3D printing of granular double network elastomers
Imagine you could 3D print agile, lightweight soft grippers that if combined with appropriate detection and navigation systems, were capable of harvesting raspberries, strawberries, and cherries without damaging them. The same soft gripper could be used to harvest significantly heavier objects, such as apples, pears, or persimmons without dropping them. Building such versatile grippers that have a much wider dynamic force range than what is currently available would open up entirely new possibilities for their use – for example within farming, the automation of the displacement of delicate objects within industrial processes, and with additional work also in the biomedical field, for example for the rehabilitation of patients.
Within this PhD project, you will introduce an elastomer microparticle-based ink that can be 3D printed into granular double network elastomers through direct ink writing (DIW). In the first part of the PhD project, you will learn different methods to fabricate elastomer-based microparticles, process them into 3D printable inks, characterize the rheological properties of these inks and relate them to their 3D printability. In the 2nd part of the project, you will convert 3D printed objects into granular double network elastomers and study the influence of their composition and microstructure on the mechanical properties. In the 3rd part of the project and in collaboration with a soft robotics lab, you will process your novel ink into cm sized soft grippers that can be used, for example to harvest raspberries. You will study the influence of the elastomer microstructure and composition on the performance of this gripper.
PhD opening: 3D printing of ion-reinforced granular double network elastomers
The formulation of polymers into soft microparticles is attractive as it enables direct ink writing (DIW)-based 3D printing of a much wider range of polymers than what is possible if precursor solutions are directly 3D printed. We showed that the 3D printed structures can be processed into granular double network systems that display a remarkable stiffness. However, the granular structure of the resulting double networks often compromises their toughness. To address this limitation, this PhD project aims at ionically reinforcing granular double network elastomers to increase their toughness without sacrificing their stiffness. To achieve this goal, you will synthesize elastomer precursors that can be ionically crosslinked. You will process these elastomer precursors into microparticles, convert them into 3D printable inks and characterize the rheological properties of these inks. You will relate the rheological properties of the inks to their 3D printability. In the 2nd part of the project, you will solidify the ionically reinforced 3D printed structure by forming ionically reinforced granular double network elastomers. You will study the influence of the microstructure and the local composition of these materials on their mechanical properties. In the 3rd part of the project, you will 3D print these materials into dampers that can be used, for example, within soft robots.
PhD opening: 3D Printing of Load-Bearing Double Network Granular Hydrogel-Based Soft Actuators
Single-network hydrogels typically suffer from a trade-off between stiffness and toughness. This limitation can be overcome if hydrogels are formulated as double networks (DNs). Unfortunately, the processing of DN hydrogels is involved such that they cannot be 3D printed. We recently overcame this limitation by introducing double network granular hydrogels (DNGHs) composed of jammed microgels that are firmly connected through a second percolating hydrogel network. These DNGHs combine the excellent mechanical properties of DN hydrogels with the 3D printability of jammed microgels. This project takes advantage of these findings to locally vary the composition of double network granular polymers to enable their use for soft actuation. Within this project, we will study how the structure and local composition of DNGHs influence their responsiveness to different external stimuli and leverage these insights to build soft actuator demonstrators.
PhD opening: 3D Printing of Shock Absorbing Meshes
Inspired by the fabrication of the mussel byssus, this collaborative project aims at establishing a method to in situ and sequentially covalently and ionically crosslink functionalized polymers. Thereby, we aim at controlling the structure of the resulting fibers from the nm up to the 100s of µm length scale. You will systematically study the processing-composition-structure-mechanical property relationship and use this newly generated knowhow to design fibers that display an unprecedented combination of stiffness and toughness.
We are looking for a highly motivated candidate that likes working in an interdisciplinary environment on a challenging project. A successful candidate should have a background in material science, chemistry, chemical engineering, physical chemistry, nanotechnology or related subjects.
If you are interested, please send a CV and a motivation letter to [email protected].