A Nature-Inspired Approach Towards the Development of an Intrinsically-Auxetic Polymer

About the project

About the Project Please note, there is no funding attached to this project. All tuition fees and any other associated costs (including bench fees) must be financed by the student. Please consider this before submitting your application. The Industry and Innovation Research Institute (I2Ri) draws on talents, expertise and facilities across Sheffield Hallam University. The vision is to be the leading provider of applied research excellence delivering materials, computing, science and engineering innovations meeting the development needs of industry. PhD Research Topic Auxetic materials have a unique behaviour where they undergo lateral expansion when subjected to axial extension. This counter-intuitive behaviour results in auxetics having enhanced properties like high energy absorption, noise reduction, fracture toughness, and high indentation resistance, unachievable by conventional materials which show lateral contraction under axial extension. Auxetic behaviour is scale-independent, and it can thus be observed at the macroscopic level down to the molecular level. Typically, auxeticity is derived from porous geometries as opposed to the inherent properties of a material. However, introducing porosity can reduce the overall strength of a material compared to its bulk and the material may be more prone to failure, particularly around the pores. A material that is intrinsically auxetic, i.e., derives its auxeticity from the molecular level, would avoid porosity related weakening whilst simultaneously allowing for fine-tuning desired properties. Although naturally occurring molecular level auxetics have been known since 1944, it was only in 2018 when the world’s first molecular-level synthetic auxetic material was developed - which has been a long-standing goal within the auxetics community. This project adopts a nature-inspired approach towards the development of a full-scale intrinsically auxetic polymer – the first of its kind. Crystalline cellulose I β , obtained from kraft-cooked Norway spruce, has a negative Poisson's ratio and is therefore auxetic. Molecular mechanics simulations have previously been performed based on crystalline cellulose I β which highlight the predominant deformation mechanisms responsible for its auxetic behaviour. This work was later extended to develop analytical and finite element models of the 2D projections of crystalline cellulose I β . The current project will now look to validate the modelling through additive manufacturing and experimental mechanics. Building on this, a comprehensive 3D model inspired by crystalline cellulose I β will be developed, fabricated, and optimised using a combination of finite element simulations and experimental validation By extending this framework to a fully three-dimensional system, this nature-inspired approach aims to bridge the gap between molecular auxeticity and scalable, high-performance materials. The successful candidate will join a vibrant, interdisciplinary research team working across materials science, mechanics, and advanced manufacturing. You will have access to high-performance computing, and state-of-the-art 3D printing and mechanical testing facilities. You will be able to participate in national and international conferences, public engagement activities, and enhance your visibility within the scientific community. You will be provided relevant training, mentorship opportunities, and many more exciting ways to grow your skills. We are excited to hear from creative, curious, and enthusiastic candidates who are passionate to use science and engineering to design the next step towards an intrinsically auxetic polymer! Eligibility All applicants should hold a strong undergraduate degree (2.1 or above) and/or a relevant masters qualification (or expectation of the same). Related disciplines include Mechanical Engineering, Materials Science, or a closely related subject (e.g. Applied Mathematics, Computing, or Physics). Knowledge of mechanics, computational modelling, or additive manufacturing would be desirable. A Master’s degree in a related area is desirable. We welcome applications from all candidates irrespective of age, pregnancy and maternity, disability, gender, gender identity, sexual orientation, race, religion or belief, or marital or civil partnership status. International candidates are required to provide an IELTS certificate with a score of at least 6.5 overall, and a minimum of 6.0 in all components. For further information on English Language requirements, please click here . For further details on entry requirements, please click here. How to apply All applications must be submitted using the online application form . In your application, be sure to include the title of the project that you are applying for. As part of your application, please upload: · A research proposal (max. 1500 words) in your own words, briefly outlining the proposed research, the current knowledge and context referencing key background literature; a proposed methodology or approach to answer the key questions, and any potential significance or impact of the research · Copy of your highest degree certificate · Non-UK applicants must submit IELTs results (or equivalent) taken in the last two years and a copy of their passport. Applicants must provide 2 references, with at least one to be academic. References must be received directly from the referees. We strongly recommend you contact the lead academic (Dr Shruti Mandhani - S.Mandhani@shu.ac.uk ) , to discuss your application. For information on how to apply please visit https://www.shu.ac.uk/research/degrees

Research areas