Paramagnetic muon states in mesoporous carbon materials

• Published in: Journal of physics. Conference series Vol. 551; no. 1; pp. 12040 - 7
• Main Authors: Macrae, R M, Upchurch, C, Rose, D K, Miyake, Y, Koda, A, Lord, J S, Shuttleworth, P S
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.01.2014
• Subjects: Carbon; Constants; Density functional theory; High temperature; Hydrophilicity; Hydrophobicity; Low temperature; Muons; Physics; Pyrolysis; Radicals; Starches; Voids
• ISSN: 1742-6596; 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/551/1/012040

We present results of longitudinal field repolarisation measurements carried out at J-PARC and ISIS on the "green" functional carbon materials Starbon 300 and Starbon 800, synthesized using starch as a template and subjected to pyrolysis treatments at different temperatures (300°C and 800°C respectively); pyrolysis at low temperature may be expected to yield a material retaining more of the "hydrophilic" properties of the original starch material in its chemically active voids, while high temperature pyrolysis may be expected to lead to "hydrophobic" voids and a more graphitic material. The hydrophilic material shows a larger repolarising fraction than the hydrophobic material, with a hyperfine constant on the order of 200-300 MHz. This is likely to be a superposition of the repolarisation of multiple radicals. Several candidate and model species are investigated through accompanying density functional theory calculations.