- Laser-generated ultrasound study #4: 200 micron fibres: MWCNT + PDMS: 4 x 1 dip MWCNT/xylene, 4 x 1 dip MWCNT/xylene/acetone, 2 x integrated fibre. Test for reproducibility. Test fibres against each others. Determined that the fMWCNT xylene coated fibres show flatter spectra (wider bandwidth) and the fMWCNT gel coated fibres generate enhanced ultrasound pressures compared to first generation integrated fMWCNT/PDMS coatings.
- Extensive investigation – have achieved good ultrasound generators using MWCNTs and PDMS. Can we enhance this? Explore range of materials including SWNTs, DWNTs, meso-carbon, carbon nanofibres, carbon black etc. Have functionalised a range of carbon nanomaterials and deposited on to slides using a drop casting deposition technique. Next step – ultrasound generation measurements.
- Characterised functionalised carbon materials using Raman spectroscopy.
- Synthesis of tiopronin capped Fe3O4 nanoparticles. Synthesis of oleic acid capped Fe3O4 nanoparticles – oleic acid capped nanoparticles dispersed in octadecene (high bpt solvent) and NPs do not precipitate out well with EtOH.
- Develop coatings on planar substrates using Fe3O4 NPs and PDMS. Some Fe3O4 NPs used as synthesised and some set aside and freeze dried. Coatings using Fe3O4 NPs as synthesised – NPs drop cast onto planar substrate (cover slip) and very crudely, using ‘doctor blading’ technique, a thin coating was achieved. After air-drying, substrate immersed in PDMS forming bilayer composite coating. Alternatively, freeze dried NPs directly incorporated into PDMS and drop cast onto planar substrate. Thin bilayer composite coating results in ultrasound generation, whereas no detectable ultrasound signal using direct integration coating strategy. Advantage of incorporation of magnetic nanoparticles for MRI?
- Direct deposition onto fibre shows comparable results. Preliminary measurements show that rapid alteration of magnetic field results in heating of dip coated film – can concept of magnetic hyperthermia be used for ultrasound generation?
Sacha Noimark
Sacha Noimark, May 2015: Exploration of new materials for laser-generated ultrasound