3D forming of cellulosic biopolymer materials using electrohydrodynamic atomisation - Project ID SEBE0012

Three-dimensional forming refers to the fabrication of structure through layer-by-layer deposition of material using a printer head, a nozzle or other printing techniques. It is broadly used in applications including automobile manufacturing, aerospace manufacturing and medical applications. 3D forming enables lighter structure of complex geometries, through ‘direct forming’ process thus with low cost and high production rate and additionally, the fruition of personalised products and mass customisation (e.g. forming implants of personalised shapes or tailored structure in tissue engineering and wound-healing applications).

Cellulose, one of the most abundant polymers on earth, has attracted substantial industrial and research interests in a wide range of applications. Nanocellulose, including cellulose nanofibrils (CNF) and nanocrystals (CNC), have extraordinary properties and valuable potentials in the area such as in biomedicine, composite and packaging materials and electric devices and so on, because of their renewability, biocompatibility and biodegradation potentials coupled with improved mechanical strength, lightweight properties, optical properties, barrier properties and structuring capabilities. A lot of attempts have been made to process cellulose structures using conventional 3D printing techniques (e.g. extrusion-based or droplet-based), although some challenges and shortages have been seen.
Electrohydrodynamic atomization (EHDA), also called electrospray technique, is a versatile processing method that utilises both electric and hydrodynamic force applied on liquid. The latter will be delivered through a nozzle and deformed in a stable cone-jet mode at the tip. The jet beneath the cone is eventually broken up into small droplets (atomisation). Recent study has shown that structures as small as 20µm can be deposited under the stable jet, which could be developed as a novel 3D forming processing method for cellulose structures of micron or submicron range.

One of the biggest challenges for forming cellulose structure using the above method is the preparation of feedstock fluids containing CNF/CNC, because the formation of stable cone-jet mode in EHDA is determined by the competition of the electric stress and the surface tension stress on the liquid-gas interface and by the kinetic energy of the liquid leaving the nozzle. Various form of feedstock have to be prepared and characterised before being applied in the EHDA process. Possible works may include the investigation of rhological and electrical properties of feedstock fluids, for example.

The project may also have an opportunity to an intra university collaboration with School of Applied Science to form cellulosic biopolymer structure with tailored biochemical functionality (e.g. antimicrobial equipment), by the functionalisation of cellulose molecules or incorporation of functional chemicals during the preparation of feedstock fluid.

Academic qualifications
A first degree (at least a 2.1) ideally in Materials Science with a good fundamental knowledge of fluid mechanics.

English language requirement
IELTS score must be at least 6.5 (with not less than 6.0 in each of the four components.) Other, equivalent qualifications will be accepted. Full details can be found here https://www.napier.ac.uk/research-and-innovation/research-degrees/application-process

Essential attributes:
• Experience of fundamental analytical laboratory skills.
• Competent in rheometric, spectroscopic and imaging techniques.
• Knowledge of cellulosic polymers.
• Good written and oral communication skills.
• Strong motivation, with evidence of independent research skills relevant to the project.
• Good time management.

Desirable attributes:
Knowledge of biomedical processes and applications, knowledge and experience of polymer chemistry, knowledge and experience of 3D printing and/or other material deposition processes, knowledge of material design processes.

When applying for this position, please quote Project ID SEBE0012