Materials research to benefit from SANS instrument project

Hamilton, ON – Nearly two decades after McMaster University’s Bert Brockhouse was awarded the Noble Prize in Physics for his pioneering contributions to the field of neutron scattering, researchers from the institute that bears his name was awarded more than $3-million by the Canada Foundation for Innovation (CFI) last week to establish Canada’s first small angle neutron scattering (SANS) instrument.

In roughly four year’s time, a beam line buried 6 metres below the ground will use neutrons from McMaster’s Nuclear Reactor to test and understand nanostructure in materials as diverse as biological membranes, plastics and superconductors.

Experimental condensed matter physicist Bruce Gaulin, director of the Brockhouse Institute for Materials Research (BIMR) and leader of the multidisciplinary project Small Angle Neutron Scattering (SANS) for Advanced Characterization of Nanostructure in Materials, explains that neutrons are scarce resources both within Canada and internationally. In Canada, only McMaster’s nuclear reactor and the NRU nuclear reactor in Chalk River are capable of supporting such an advanced characterization program.

Gaulin notes that while Canadian researchers can – and do – access other international SANS instruments, these facilities are oversubscribed by factors of three or more. This means that Canada’s scientists and engineers are competing to use SANS instruments that only approve one proposal for every three or four submitted, severely limiting Canadian progress in this area.

“It is truly a unique opportunity,” says Gaulin, who also holds the Brockhouse Chair in the Physics of Materials, “McMaster is going to be providing the Canadian materials science community with a powerful instrument to probe the structure of materials on the nanoscale. Materials scientists in Canada are not presently competing on a level playing field with scientists from other technology-driven economies. This infrastructure will allow them to better ‘compete to win’.”

Small angle neutron scattering exploits the unique properties of the neutron as a probe of matter. The materials that will be explored by McMaster’s SANS instrument will have sub-structures with a characteristic size of about one nanometer, or one billionth of a meter.

Complicated molecular substructures such as polymers can therefore be understood in greater detail under different conditions and temperatures. Gaulin offers the example of determining how long a single polymer strand is within a polymer melt: are the polymers intertwined with each other like strands of spaghetti or do they coil together to form balls within the melt? Understanding the structure of various technologically desirable materials is of fundamental importance to establishing structure-property relationships, which can then be used to understand and manipulate their physical properties.

“The SANS instrument will be a new and powerful vehicle for the creation of knowledge about innovative plastics and polymers, unique biomaterials and novel magnetic and superconducting materials.” said Mo Elbestawi, vice-president, research and international affairs at the university.

The research interests of the cohort of co-applicants on the SANS project covers the suite of neutron scattering applications: chemical engineers Emily Cranston, Todd Hoare and Robert Pelton, chemist Harald Stöver, and physicist Kari Dalnoki-Varess are interested in nanostructure and pattern formation in polymeric and polymeric-composite materials; biochemist Richard Epand, physicists Cecile Fradin, Maikel Rheinstadter and Dalnoki-Varess research nanostructure in biological and biomimetic materials; Gaulin and chemist Yuri Mozharivskij work in nanostructures in new magnetic materials, and Gaulin is also interested in magnetic flux lattice nanostructure within type II superconductors.

Reported by Danelle D’Alvise, Research Communications, McMaster University