Development of advanced fatigue-resistant hydrogel composites

Hydrogels are 3D polymer networks containing water. The main integral parts of tissues and organs in animals and plants are all composed of hydrogels. Thus, recent years have witnessed fast growth in developing various artificial hydrogels due to their promising applications in bio-medical science and healthcare, e.g., artificial tissue, artificial cartilage, and artificial heart valves. In most of these potential applications, hydrogel components are subjected to cyclic mechanical loadings, e.g., for an average person, the artificial cartilage must sustain around 1 million cycles of stress with a peak around 4 ~ 9 MPa per year. Thus, the artificial hydrogels must exhibit good mechanical properties. Unfortunately, compared with their natural partners, artificial hydrogels have much poorer mechanical properties, i.e., lower mechanical strength, lower fracture toughness, and lower fatigue-resistance. By comparing natural and artificial hydrogels, it is found that different from artificial hydrogels which are homogeneous polymer networks, the natural ones are usually inhomogeneous, containing biomineral particles, hard tissues, and ordered/hierarchical structures. The supreme mechanical properties of natural hydrogels are potentially related to their inhomogeneous structures.

Inspired by the heterogeneous natural hydrogels, this project aims to develop artificial hydrogel composites with high mechanical strength, high fracture toughness and high fatigue-resistance. Biocompatible hydrogel composites containing reinforcing particles/fibres and various inner structures/lattices will be synthesised. Besides the mechanical testing at macro-scale, microscopic observations of the deformation of the embedded particles/fibres and inner structures/lattices will also be conducted by advanced optical techniques such as polarized microscope, fluorescence imaging and mechanochemical technique. Theoretical modelling will also be performed. Model simulation results will be compared with experimental data to study the structure-property relation and reveal the physical mechanisms for the improved mechanical properties of hydrogel composites. The whole work packages will include gel composite fabrication, mechanical testing, optical characterisation, and theoretical modelling.

Faculty: Engineering and Environment

Department: Mechanical and Construction Engineering

Principal Supervisor: Dr. Sherry Chen

Recent publications by supervisors relevant to this project 

• “A structural gel composite enabled robust underwater mechanosensing strategy with high sensitivity”, Advanced Functional Materials, 2201396 (2022).
• “Spatially and reversibly actuating soft gel structure by harnessing multimode elastic instabilities”, ACS Applied Materials & Interfaces 13 (30), 36361–36369 (2021).
• “Controlled cooperative wetting enabled heterogeneous structured 3D morphing transducers”, Advanced Materials Interfaces 8 (2), 2001211 (2021).
• “A flexible topo-optical sensing technology with ultra-high contrast”, Nature Communications 11 (1), 1–7 (2020).

Eligibility and How to Apply

Qualification

Applications are invited from exceptional candidates who have a good first or upper second class degree (or equivalent) in engineering or materials science. Students who are not UK/EU residents are eligible to apply, provided they hold the relevant academic qualifications, together with an IELTS score of at least 6.5. This project is well suited to motivated and hard-working candidates with a keen interest in design, materials and manufacturing. The applicant should have excellent communication skills including proven ability to write in English.

For more information and informal enquiries please contact: Dr Sherry Chen

Further details of the application process and entry requirements can be found here: https://www.northumbria.ac.uk/research/postgraduate-research-degrees/how-to-apply

Deadline for applications: 1st December for March (following year) start; 1st July for October (same year) start.

Start Dates: March and October of each year