Research Studentship in Mechanics and Physics of Soft Materials

3.5-year DPhil studentship 

Project: Multiscale physics of deformation and failure in polymer networks

Supervisors: Prof Laurence Brassart

Many soft materials, such as elastomers and hydrogels, consist of networks of interconnected polymer chains. Their properties can be tuned through molecular composition, polymer chain length, network architecture, and interactions with solvents, resulting in a broad range of mechanical behaviours and functionalities. This versatility underpins applications ranging from soft structures and adhesives to medicine, energy, and sustainability technologies.

A major challenge for the design of these materials is to understand and predict their deformation and failure under external stimuli, including mechanical loads, exposure to degrading environments, or a combination of the two. An important example is delayed fracture [1,2], whereby an elastomer subjected to a constant load well below the threshold for rapid fracture can fail after a prolonged period. Open questions include the relative roles of viscoelastic relaxation and time-dependent chain scission, and how these mechanisms are influenced by molecular and network parameters. Addressing these questions requires a modelling framework capable of connecting molecular-scale processes to the macroscopic response through an explicit description of the polymer network.

This DPhil will develop a mesoscale framework to predict the time-dependent deformation and failure of polymer networks from their underlying chain-level physics. Building on previous work in our group [3,4], we will use a coarse-grained discrete-network model to explicitly represent the network architecture. A major focus will be the development of physically grounded descriptions of viscoelasticity and time-dependent chain scission, drawing on statistical mechanics and thermodynamics [5,6]. The framework will be used to investigate delayed fracture and related failure phenomena, with predictions tested against experimental data and, where appropriate, molecular simulations.

This project would particularly suit a student who enjoys physical and mathematical modelling, and who is excited by challenging theoretical problems in soft matter physics and mechanics. Candidates are not expected to have prior experience in this specific area, but intellectual curiosity, a desire to understand problems from first principles, and strong analytical and computational skills are essential. A background in mechanics, physics, applied mathematics, materials science, or chemistry could provide a suitable starting point.

References:

[1] Wang, J., Zhu, B., Hui, C., Zehnder, A.T., 2023. Delayed fracture caused by time-dependent damage in PDMS. J. Mech. Phys. Solids 181, 105459. [

2] Wang, S., Fan, Z., Siavoshani, A., Wang, M., Wang, J., 2025. Fresh considerations regarding time-dependent elastomeric fracture. Extreme Mech. Lett. 74, 102227.

[3] L. Mangas Araujo, L. Brassart, 2025. Force-biased chemical degradation in rubbery networks: Insights from discrete network simulations. Extreme Mech. Lett. 77, 102344.

[4] L. Mangas Araujo, L. Brassart, 2026. The role of chain stretch heterogeneity on the uniaxial failure response of rubbery networks. Mech. Mater. 215, 105599.

[5] J. Zhu, L. Brassart, 2026. Confirmation-mediated chain kinetics of polymer scission under tension. Arxiv preprint arXiv:2608.24378v1

[6] R. Wagner, M. Silberstein, 2025. A foundational framework for the mesoscale modeling of dynamic elastomers and gels. J. Mech. Phys. Solids 194, 105914.

Eligibility

This studentship is funded through the Department of Engineering Science and is open to Home students.

Award Value

Course fees are covered at the level set for UK students (at least £10,940 p.a.).

The stipend (tax-free maintenance grant) is at least £21,805 p.a. for the first year, and at least this amount for a further two and half years.

Candidate Requirements

Prospective candidates will be judged according to how well they meet the following criteria:

• A first class or strong upper second-class undergraduate degree with honours (or equivalent) in Engineering, Physics, Mathematics, Materials, or Chemistry

• Excellent English written and spoken communication skills

• Strong analytical and mathematical skills

• Programming experience (e.g. Matlab, Python, C/C++,…)

The following background is desirable but not essential:

• Foundations in Continuum Mechanics and/or Thermodynamics and/or Statistical Physics

Application Procedure

Informal enquiries are encouraged and should be addressed to Professor Brassart (laurence.brassart@eng.ox.ac.uk).

Candidates must submit a graduate application form and are expected to meet the graduate admissions criteria. Details are available on the course page of the University website.

Please quote 27ENGMM_LB in all correspondence and in your graduate application.

Application deadline: noon on 2 December 2026 (In line with the University admissions deadline set by the University)

Start date: October 2027