Soft condensed matter physics

Our research encompasses biophysics and biological physics, nanoscience and nanotechnology, fundamentals of phase transitions, and measurement techniques using light, X-ray and neutron scattering.

People

Interests:

  • Colloidal crystallization and vitrification
  • Light scattering techniques
  • Phase transitions
  • Phase behaviour of colloidal and molecular fluids
  • Cryobiology
  • Desiccation biology
  • Membrane phase transitions
  • Protein-ligand interactions
  • Small angle Neutron and X-ray scattering
  • Particle characterization.

Interests: 

  • Condensed matter physics
  • Preparation of particles with novel optical properties
  • Particle characterisation
  • Particle dynamics of concentrated colloidal suspensions
  •  Kinetics of crystallisation in one and two component colloidal systems of hard spheres
  • The glass transition and glassy states of matter.

Collaborators

Our research is conducted with expert collaborators from around Australia and the world.

  • Professor Karen Koster, University of South Dakota, USA
  • Dr Eric Perez, Ecole Normale Supérieure, Paris, France
  • Dr Hans Joachim Schöpe, University of Tübingen, Tübingen, Germany
  • Professor Wilson Poon, School of Physics, University of Edinburgh
  • Dr Vincent Martinez, School of Physics, University of Edinburgh
  • Dr Ben Kent, Helmholtz-Zentrum Berlin für Materialien und Energie, Potsdam, Germany
  • Dr Thomas Hauss, Helmholtz-Zentrum Berlin für Materialien und Energie, Potsdam, Germany

Research areas

Our research is conducted in three primary areas: phase transitions in colloidal suspensions, freezing and dehydration in biology, and light, neutron and x-ray scattering in biology and physics.

Research goals

  • To understand crystallization, melting and the glass transition at a fundamental level.
  • To develop improved experimental methods for the study of crystallization and glass formation in colloidal systems.
  • To understand the effects of polydispersity on colloidal crystallization.
  • To develop methods for influencing the type and rate of colloidal crystallization using external fields.

Methods

  • Dynamic light scattering (DLS) and Static Light Scattering (SLS)
  • Bragg crystallography
  • Molecular Dynamics Simulations

This video (MP4, 2.4 MB, 1 min) shows a time lapse of crystallization followed by settling of the crystals under gravity. The right hand sample shows heterogeneous crystal growth.

We also conduct studies in 2 dimensional systems. This video (MP4, 1 MB, 11 seconds) shows 2-D Brownian motion in a dense 2-D fluid of particle trapped at an interface between 2 liquids.

Applications

  • Much of our research is focussed on improving our understanding of the fundamental processes of crystallization and the glass transition, an area of classical physics which is still poorly understood.
  • A better understanding of these processes is of importance for a range of industries in the are of materials science.
  • Colloidal crystals have significant potential as the basis for optical devices and other nanotechnologies.

Research goals

  • To understand how biological membranes respond to changes in water content, with emphasis on understanding the mechanisms of desiccation and freezing damage.
  • To understand the physical mechanisms behind the ability of a range of solutes to limit damage to biological cells during freezing and/or dehydration.
  • To understand the behaviour of biological water glasses under conditions used for cryopreservation of medical tissue.
  • To be able to predict the longevity of biological tissue stored in a frozen or dehydrated state.

For more detailed information on Cryobiology, visit the cryobiology and anhydrobiology of cells web page prepared by Professor Joe Wolfe (School of Physics, UNSW) and Professor Gary Bryant (School of Applied Sciences, RMIT).

We also work with ecologists and plant physiologists to understand freezing, desiccation and heat stress in plants. A recent example is outlined in this paper published in Plant Physiology.

Methods

  • Small angle X-ray diffraction (SAXS), including synchrotron SAXS
  • Small angle Neutron scattering (SANS)
  • Differential Scanning Calorimetry (DSC)
  • Solid State Nuclear Magnetic Resonance (SSNMR)
  • Dynamic light scattering (DLS) and Static Light Scattering (SLS)

Applications

  • Agronomy – development of crops and plants with frost/drought resistance
  • Genetic resources preservation (DNA, seeds, sperm, eggs...)
  • Medical cryopreservation for transplants, transfusions, IVF etc
  • Cryopreservation of cell lines for a range of medical research, including research into cancer.

We currently have a range of research projects underway which make use of scattering techniques. These include:

  • The study of biological and non-biological macromolecules (proteins, polymers etc) using Dynamic Light Scattering combined with small angle Neutron, X-ray and Light scattering techniques. These techniques are important for the determination of the size and shape of macromolecules in solution, and for studying how the molecular size and shape are influenced by changing conditions (pH, temperature etc).
  • A study of the effects of sugars, proteins and other molecules on the structure of biological membranes using small angle X-ray and Neutron scattering.

Research students

Research candidates past and present have undertaken cutting-edge research projects with the Centre for Molecular and Nanoscale Physics.

PhD students

  • Catherine Carnovale (PhD - submitted) – Investigation of shape and size effects on the efficacy and toxicity of nanoparticles (with Associate Professor Vipul Bansal and Dr Ravi Shukla)
  • Professor Ricardo Mancera, Curtin and Dr Chris Garvey, ANSTO).
  • Uzma Malik (Masters) – Interactions of phospholipid membranes with DMSO and Isoprene. (with Dr Chris Garvey, ANSTO).
  • Reece Nixon-Luke (PhD) – Differential Dynamic Microscopy and Dynamic Light Scattering studies of Bacterial Motility (with Dr Vincent Martinez, University of Edinburgh).
  • Stephen Hannam (PhD) - Investigation of crystallization inhibitors through molecular dynamics simulation (with Senior Supervisor Professor Peter Daivis)

PhD students

Master of Applied Science

  • Jason Walsh – 2010 Structured Light Fields for the Creation of Colloidal Crystals. (with Associate Professor Phil Wilksch)
  • Mr Joe Harland – 1998 Kinetics of the Fluid to Crystal Transition in Dense, Hard Sphere, Colloidal Suspensions. Now Retired.
  • Master of Technology Mr Phil Francis – 2002 A Bragg Scattering Spectrometer. Now Manager of Electron Microscopy at the RMIT Microscopy and Microanalysis Facility (RMMF) at RMIT.

Facilities

Our researchers use a range of facilities centred around state-of-the-art light scattering equipment, and have access to other major facilities at RMIT, Australia and throughout the world.

The major pieces of equipment are:

  • A Bruker microfocus Small angle X-ray Scattering (SAXS) instrument. Has capabilities for SAXS and WAXS, with simultaneous DSC. Includes cells for powders, solids, liquids and a flow through cell. Further details can be found here.
  • An ALV - two colour cross-correlation multiple-scattering-suppression spectrometer. This instrument is unique in the world, and is capable of dynamic and static light scattering measurements in suspensions which are too turbid for normal light scattering.
  • An ALV – 5022F FAST correlator and compact goniometer. Facility for Static and Dynamic Light Scattering, Zimm plots, Particle size distribution determination, Depolarized light scattering, Fast correlation capability. Capable of measuring size and shape of nanoparticles in solution from spheres to rods.
  • An ALV Compact goniometer, with motorised detector suitable for static and dynamic light scattering. Optimised for the study of very slow dynamics in colloids and gels.
  • An RMIT built Bragg angle spectrometer (for studying crystallisation kinetics in colloidal suspensions).

In addition to our local facilities, we use the following facilities at RMIT and elsewhere:

We also make use of major neutron and x-ray scattering facilities, both in Australia and overseas:

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Acknowledgement of country

RMIT University acknowledges the people of the Woi wurrung and Boon wurrung language groups of the eastern Kulin Nation on whose unceded lands we conduct the business of the University. RMIT University respectfully acknowledges their Ancestors and Elders, past and present. RMIT also acknowledges the Traditional Custodians and their Ancestors of the lands and waters across Australia where we conduct our business.