The UK Neutron & Muon User Meeting (NMSUM) has been postponed to April 2021. However, we are planning a series of online discussions on science using neutrons and muons with members of the community presenting their work.
The second of these online meetings will be based around the Soft Matter and Bioscience session that would have taken place at NMSUM. This will take place on the afternoon of 20 July 2020, and an outline programme is below.
If you would like to attend the webinar, please register here. There is no charge for the meeting; registering will allow us to send you a Zoom link for the meeting nearer the time.
13.30 Introduction (10 mins)
13.40 Martin Hollamby (Keele) (15 mins)
Using small-angle scattering to probe the self-assembled structures formed by functional hydrophobic amphiphiles
This talk will focus on solution-state assemblies of alkyl-C60 molecules. Similarly to conventional amphiphiles, these assemble into micelles or more extensive liquid-crystalline structures and consequently are referred to as "hydrophobic amphiphiles". Structures formed in solution by these molecules have been thoroughly characterised, in particular using small-angle scattering with both neutron and X-ray sources. One of the more extensive structures formed to-date is a structured gel, which exhibits a reasonable degree of photoconductivity. However as it remains relatively disordered in the bulk, the photoconductivity could be improved. An attempt was therefore made to align these gel fibres in magnetic fields up to 16T. Results were collected on both SANS2D (ISIS, UK) and D33 (ILL, France), exploiting the wide simultaneous Q-range and large detector areas / pixel numbers that are available. Not only was the alignment successful, the extent of alignment was found to be related to the field strength and gelled materials showed very slow relaxation in alignment after removal from the magnetic field.
14.00 Natasha Shirshova (Durham) (15 mins)
Microstructure formation in epoxy based multifunctional electrolytes
Structural supercapacitors can simultaneously store electrical energy and withstand mechanical load providing significant weight or/and volume savings for example in the automotive and/or aerospace industry. Multifunctional electrolyte is an essential part of a structural supercapacitor determining its performance. However, preparation of a multifunctional electrolyte is a complex issue, as the two main properties i.e. ionic conductivity and mechanical properties have an inverse relationship. Previous studies have shown that electrolytes with a bicontinuous structure have a promising set of properties, as one of the phases is responsible for mechanical performance whereas the phase provides ion conduction. Bicontinuous electrolytes can be prepared through reaction induced phase separation, where initially homogeneous system starts to phase separate as polymer begins to form and its solubility in the liquid electrolyte is reducing. The difference between two competing reactions, polymer formation and phase separation, determines the microstructure and properties of the resulting dual phase electrolyte. The formed microstructure is one of the factors which affects performance of the resulting structural electrolytes and that is why understanding of the microstructure formation and find ways of controlling it is essential to develop better structural electrolytes. The talk will focus on the structure of electrolytes based on epoxy resins and discuss the effect of composition on the microstructure formation of the epoxy based structural electrolytes.
14.20 Heloisa Bordallo (University of Copenhagen, Denmark) (15 mins)
Filling in the gaps: a better understanding of dental cement durability
Oral health is an integrated part of the public wellbeing, and does not only affect the quality of life, but also the healthcare system through related economic costs. Despite great global progress in oral health related issues, dental caries is still a major problem that affects both children and adults. Among dental restorative materials glass ionomer cements (GIC) are of great interest, since they have the ability to bond to the tooth structure. Furthermore, fluoride is slowly released adding to the anticariogenic benefits of the material. GIC's poor mechanical strength is however a disadvantage, and improved knowledge on this subject can bring potential development. One possibility is to advance our understanding of the dynamics of the aqueous solution used to prepare the GIC and how it is modified under confinement.
Under these lines, by combining neutron spectroscopy to imaging analysis and calorimetric studies we were able to visualize the GIC structure and follow the evolution of the nanoscale mobility of the hydrogen atoms, mostly from water, during the maturation process of the material. However, as the understanding water dynamics in such complex hierarchical structure is difficult, the experimental data was combined with preliminary classical molecular dynamics simulations (MD). This unique approach opens new possibilities to better explore all the information contained in the neutron spectroscopy data. In this talk I will discuss how these findings contribute to the understanding of the nature of the hydration in the GIC and how this knowledge can be applied towards the development and improvement of dental restorative materials.
M. C. Berg et. al. ACS Appl. Mater. Interfaces, 10, 9904–991; M.C. Berg et. al. Eur. Phys. J. Special Topics, 225, 775–79; A.R. Benetti et. al. Sci. Rep. 5, 8972.
14.40 Break (10 mins)
14.50 Dave Adams (Glasgow) (15 mins)
Determining the underlying structures in supramolecular gels
Supramolecular gels are formed when small molecules self-assemble into long anisotropic structures that entangle to trap the solvent. Typically, structural changes occur on drying and so techniques are required that allow the underlying structures to be probed in the gel state. I will describe how we have been using small angle scattering to understand the structures that are formed in both single and multicomponent systems.
15.10 Hanna Barriga (Karolinska Institutet, Sweden) (15 mins)
15.30 Wuge Briscoe (Bristol) (15 mins)
Self-assembly of bacterial lipids
Lipopolysaccharides (LPS) and lipoteichoic acid (LTA) are major components in the membranes of Gram-negative and Gram-positive bacteria, respectively. Detailed knowledge of their self-assembly in solution and at interfaces is critical to understanding their roles in causing sepsis and to design of novel effective antibacterial agents (ABAs). SANS has revealed the morphology of the self-assembled structures by these bacterial lipids in solution, complementing direct measurement of interactions between model bacterial membranes using the surface force apparatus (SFA). Our results also show the pronounced effects of multivalent cations and temperature on the self-assembled structure in solution and at interfaces.
15.50 Trevor Forsyth (Keele / ILL) (15 mins)
A molecular mechanism for transthyretin amyloidosis
Human transthyretin (TTR) is implicated in several fatal forms of amyloidosis. Many mutations of TTR have been identified; most of these are pathogenic, but some offer protective effects. The molecular basis underlying the vastly different fibrillation behaviours of these TTR mutants is poorly understood. On the basis of neutron crystallography, native mass spectrometry and modelling studies, we propose a mechanism whereby TTR can form amyloid fibrils via a parallel equilibrium of partially unfolded species that proceeds in favour of the amyloidogenic forms of TTR. It is suggested that unfolding events within the TTR monomer originate at the C-D loop of the protein, and that destabilising mutations in this region enhance the rate of TTR fibrillation.
Furthermore, it is proposed that the binding of small molecule drugs to TTR stabilises non-amyloidogenic states of TTR in a manner similar to that occurring for the protective mutants of the protein.
16.10 Close