Sacha Noimark, June 2015: Exploration of new materials for laser-generated ultrasound

• Helped developed side facing ultrasound imaging probe. In brief, angled fibre tip, MWCNT gel coating on side, sputter angled end with gold (6 x 90 second cycles), PDMS overcoat system.

• Synthesise new bactch of tiopronin capped Fe3O4 nanoparticles (susceptible to oxidation). Nanoparticles freeze-dried and a series of PDMS-Fe3O4 polymer materials were prepared at different Fe3O4 loadings, covering a 2 cm x 2 cm area of glass coverslip.

• Fe3O4 NP : PDMS composite materials were exposed to rapidly alternating magnetic field and imaged using a thermal imaging (IR) camera. Samples showed heat rise in response to field alternation, with the highest NP loaded sample indicating the greatest heat rise. Effect decreased with PDMS NP concentration.

• Preliminary experiments on magnetoacoustics. Much system optimisation needed and different hydrophone required.

• Development of Fe3O4 ‘functionalised’ MWCNTs – magnetic nanotubes developed using one-step synthetic strategy.

• Extensive investigation. Oleylamine functionalised-pyrene ligand was used to functionalise a range of carbon compounds including: SWNTs (6,5), SWNTs (7,6), DWNTs, MWNTs, carbon black, carbon nanofibres, reduced graphene oxide, nanodiamond, mesoporous carbon and the functionalised compounds were drop cast onto glass microscope coverslips. The samples were subsequently dip-coated in PDMS. A crude set up was designed to gain a preliminary indication of whether these materials were efficient ultrasound generators. The design of a more robust set up is necessary for comparison of these samples. Included in this study was a dropcast CTAB-fMWCNT-Fe3O4 sample, coated in PDMS.

• A new material was developed – Pristine MWCNTs were incorporated in a sulphur polymer. The material was dropcast onto a glass slide and ‘doctor-bladed’, such that a smooth, even coating was achieved. The samples were subsequently tested for ultrasound generation and demonstrated promising properties.

Sacha Noimark