Projects

Soft matter is everywhere. Your body, and all living things, are made of soft matter. It has many commercial applications, from polymer solar panels to post-it notes. Our projects reflect this, and include both projects aimed at achieving a fundamental understanding, and industrially funded projects.

Research projects

Our group is highly international, we have present and past PhD students and postdocs from Italy, Spain, Malaysia, India, Saudi Arabia, Greece, France, Germany, Poland, Hungary, Malta, Thailand and China, as well as the UK.

  • Start date: October 2019
  • End date: September 2022
  • Type: Modelling (main) Experimental (subsidiary)
  • Collaborations: Biocomposites Centre, Bangor University.

Summary

Resin modification requires viscous liquids to be infused (usually under pressure) into timber with the aim to fill both the cell lumen and penetrate the cell wall. This project will use Lattice Boltzmann modelling and experimental MRI expertise available within Surrey to develop an understanding of the flow of viscous liquids through the timber structure and the expertise in timber modification within Bangor to validate the models.

Objectives

  1. Use NMR / MRI to visualise viscous fluid penetration of timber
  2. Use Lattice Boltzmann modelling to develop a theoretical understanding
  3. Compare the behaviour of different fluids.

  • Start date: October 2019
  • End date: September 2022
  • Type: Experimental
  • Collaborations: Biocomposites Centre, Bangor University.

Summary

This project seeks to couple 1H NMR relaxometry and restricted diffusometry in wood with silane impregnation matrix determination to better understand hysteresis within, and irreversibility between the first and subsequent water sorption isotherm cycles of wood. The cell-level data obtained will be used to support and test models of drying shrinkage and distortion.

The project is in collaboration with colleagues at the University of Bangor where the silane impregnation will be carried out. The NMR methods are non-invasive and non-destructive so can be carried out during water sorption, whereas the silane impregnation is invasive.

Objectives

  1. Measure wood cell microstructure using 1H NMR relaxometry and/or restricted diffusometry of the water in the cell
  2. Validate this microstructure with the results of silane impregnation
  3. Measure the microstructure during two or more cycles of water desorption / adsorption using NMR
  4. Compare the results with theories published in the literature.

Project description

Liquid crystalline rubbers have an unusual coupling between the macroscopic shape of the rubber and the microscopic liquid crystalline elements. As a result these materials have complex elastic behaviour including the formation of microstructure on deformation, and spontaneous length increase of hundreds of percent on cooling.

There are many phases of liquid crystals including the nematic phase, the smectic phase which has highly anisotropic elastic properties, and the cholesteric phase which has important optical properties.They may be useful in high tech applications such as actuators in microfluidic devices.

Project description

Complex fluids such as colloids, polymer solutions and surfactant solutions, have additional internal structure in comparison to simple fluids. For example the orientation and degree of elongation of the polymer chains must be captured in a model of polymer solutions. For several of these fluids, their mechanical properties is governed by a reaction diffusion equation. These models are capable of describing the unusual flow behaviour of complex fluids such as shear banding -- where an inhomogeneous shear profile forms on subjecting the fluid to a simple shear.

Techniques used

The atomistic simulations will be performed using DLPOLY, a software package created at Daresbury Laboratory. We have about 15 years experience using DLPOLY. The code can be run on the local super-computer. Local expertise exists through a PDRA and PGR students.

Raman measurements will be performed using to local Raman facility housed in the Physics Department. Dr Alan Dalton is an expert in this area.

Objectives

  1. To undertake equilibrium atomistic simulations of graphene sheets using molecular dynamics to develop an improved understanding of its properties
  2. To investigate the mechanical properties of graphene, particularly its Raman spectra (determined from its vibrational properties)
  3. To undertake some Raman spectroscopy experiments on graphene sheets
  4. Undertake simulations of graphene in different environments (stressed, aqueous).

Project description

Recently, there has been significant interest at the fundamental level in the behaviour of carbon nanoparticles (such as carbon nanotubes and graphene). Graphene (a single layer of graphite with a hexagonal sp2 hybridised structure)is the strongest material known to man (and currently the most expensive!). The mechanical properties of graphene is not well established and its Raman characteristics, for example, have only recently been established experimentally. This is therefore an opportunity to make an impact in a young field.

This project involves developing a fundamental understanding of the mechanical properties of graphene jointly with Dr Alan Dalton. The computational component involves molecular dynamics simulation using DLPOLY software on the local supercomputing cluster. The identification of appropriate interatomic potentials will be key. The interpretation of data and production of simulated Raman spectra has not been attempted before for graphene but the technique has been implemented successfully in other systems and, provisionally, for carbon nanotubes. The results will have implications for the interpretation of spectra from carbon nanotubes too.

  • Supervisor - Richard Sear
  • Type - Computational/theoretical

Project description

The cells our bodies are made of are driven out of equilibrium by the energy-consuming process of life, and this creates gradients in the concentrations of the molecules inside them. For example, ATP the molecule many protein nanomachines burn as fuel will be higher concentrations near where they are made, at a protein machine called ATP synthase, then far away from these sources. Concentration gradients also occur in may other contexts, for example in drying paint coatings, where the moving water/air surface pushes molecules before it, creating gradients. It has been known for many years that a gradient in the concentration of one molecule or ion, can drive motion of a different molecule or ion, a process called diffusiophoresis. But recent advances have led to a renewed interest in diffusiophoresis.

In particular Joe Keddie and I, working with two postdocs, found that diffusiophoresis could lead to coatings that spontaneously formed layers during drying. This was published in Physical Review Letters in 2016. I am continuing to work on this in collaboration with Joe, and I also working on applying our increasing knowledge of diffusiophoresis to the complex dynamics inside our cells, to better understand how proteins move around inside our cells.

  • Supervisor - David Faux
  • Type – EngD project (4 years) in experiment and modelling

Techniques used

The experimental (NMR) work will be undertaken at the Schlumberger Research facilities in Cambridge, UK. The random-walk modelling will require a bespoke code which the student will develop. It will be run using Surrey’s supercomputing facilities.

Objectives

  1. To determine the microscopic length scales that control the macroscopic rheology using novel magnetic resonance imaging and optical light scattering techniques in combination with conventional tools
  2. To validate the measured length scales and macroscopic properties against existing models for non-Newtonian fluids
  3. To develop an improved understanding of the hierarchy of relevant structural lengths from the nanoscale to the macroscale to enable the design of improved complex fluid formulations with predictable rheological properties.

Project description

Complex fluids containing suspensions of colloidal particles are critical to a wide variety of industrial processes. Such complex fluids are used extensively in the petroleum industry, for well construction (drilling fluids, cements) and oil recovery (aqueous polymer and surfactant solutions). Prediction and control of the non-Newtonian rheological properties of these fluids, such as gel strength and ability to suspend non-colloid particles, is essential for successful operations. These macroscopic rheological properties are governed by the nanoscale interactions between the colloidal particles that result in phenomena such as shear banding and viscoelasticity. These properties are challenging to measure in conventional rheometers and there is considerable industrial and academic interest in developing new characterisation methods.

Schlumberger is an oilfield services company with a global footprint. Activities at the Cambridge centre focus on the development of new science and technology for well construction, with an emphasis on drilling and automation. The facilities available for this proposed project include a suite of low field magnetic resonance instruments, microscopy (optical and X-ray) platforms, conventional rheometers, and hydrodynamic flow experiments. A unique low field magnetic resonance rheometer will be a core technology, enabling the spatial variation of shear stress and non-colloidal particle migration to be visualised within complex fluids.

The project will be supervised by Dr Jonathan Mitchell (magnetic resonance) and Dr Andrew Clarke (nanoscience). Support for aspects of the project related to conventional rheology, fluid chemistry, and modelling/simulation will be provided by other scientists and engineers at Schlumberger Cambridge.