I just got back from participating in the MRS (Materials Research Society) Fall Meeting, which was held in Boston, USA from Nov 30-Dec 5 2014. The MRS meetings are held twice a year and cover a very wide range of topics such as nanomaterials, nanostructured materials, electronic materials, soft matter, energy conversion/storage etc. Advances in materials characterization techniques are also presented and discussed quite extensively including new developments in the area of optofluidics, microfluidics, imaging and spectroscopy.

This year’s fall meeting was attended by several thousand participants and there were in total about 53 parallel sessions covering a very wide area of material science fundamentals, synthesis, characterization and applications across multiple industrial sectors. With such a large variety of topics and areas of interest, I had to keep my focus on attending talks which were close to my areas of interest – namely new characterization techniques, soft matter and nanomaterial characterization and rheology.

From Malvern BDI (Bioscience Development Initiative), me and my colleague Dr.Steven Blake gave two talks, both focusing on the new applications that can be opened up through utilization of the combined Dynamic Light Scattering (DLS)-Raman Instrument, the Zetasizer Helix. The Zetasizer Helix is a new Malvern product, developed by scientists/engineers at Malvern BDI. Steve gave a talk on utilization of DLS-Raman to carry out a full characterization (length, diameter, chirality, quality) of carbon nanotubes – details can be found in this whitepaper- Characterizing Single Walled Carbon Nanotubes by combining dynamic light scattering with Raman Spectroscopy. This was presented in the session on carbon nanotubes and was well attended and well received. Discussion following the talk focussed on analysis methodology and how formulation conditions (e.g. solvent quality) can impact the results.

My talk was on a new area of generating novel insights into the gelation mechanism of complex fluids through combination of optical microrheology with Raman Spectroscopy. The Zetasizer Helix, in addition to carrying out DLS  and Raman Spectroscopy, also allows optical microrheology experiments to be carried out. In this talk I focused on how the rheology evolution of complex fluid systems such as wormlike micelles or biopolymers such as agarose can be linked to low frequency (around 170 cm-1) Raman data. This Raman band is linked to intermolecular interaction effects such as H-bonding and also is reflective of changes in water structuring as a complex fluid undergoes self-assembly and gels up confining water to nanopores. The following 2 figures illustrate the evolution of viscosity (measured through optical microrheology) in a wormlike micelle system as a function of salt addition and the connectivity with the low frequency Raman data. Details on the agarose system has been published in Journal of Chemical Physics (S.Amin et al in press). This connectivity between rheology and molecular level structural changes is a new unexplored area that has been opened up by the Zetasizer Helix and should help to develop new insights that will allow the optimization of performance enhancing formulation design rules.

Gelation in SLES/CAPB Wormlike Micelles with Salt Addition
Fig.1 Gelation in SLES/CAPB Wormlike Micelles with Salt Addition
Note-SLES/CAPB is a common surfactant base mixture found in bodywashes, shampoos.
Link of Raman Low Frequency Data with Viscosity as a function of Salt Addition
Fig. 2 – Link of Raman Low Frequency Data with Viscosity as a function of Salt Addition

The talk was presented in the session on ‘Techniques to Probe Nanoscale Properties of Soft Matter’. It was well attended and well received. Discussions focussed on new microstructural insights that the Raman data was providing.

Thanks again to the organizing committee for giving me and Steve the opportunity to present our work. Overall I really enjoyed the MRS meeting and am looking forward to the next one.

Futher reading about DLS-Raman:

A novel combination of DLS-optical microrheology and low frequency Raman spectroscopy to reveal underlying biopolymer self-assembly and gelation mechanisms

S. Amin, S. Blake, S. M. Kenyon, R. C. Kennel and E. N. Lewis

Concomitant Raman Spectroscopy and Dynamic Light Scattering for Characterization of Therapeutic Proteins at High Concentrations – Chen Zhou, Wei Oi, Neil Lewis, John F. Carpenter.

Whitepaper: Characterization of Single Wall Carbon Nanotubes (SWNTs) by combining Dynamic Light Scattering and Raman Spectroscopy

Whitepaper: Towards a unified biophysical characterization platform: Combining dynamic light scattering and Raman spectroscopy to determine protein structure and stability

Webinar: Combining dynamic light scattering and raman spectroscopy to achieve new insights into protein stability, aggregation and high order structure