Isopropanol swelling of polydimethylsiloxane for reducing gold nanoparticles to enhance photoacoustic transducer

Gold nanoparticles (Au NPs)-polydimethylsiloxane (PDMS) nanocomposite has been of particular interest in the photoacoustic (PA) transducer with characteristics of good high frequency and wide bandwidth. To form highly-efficient Au NPs-PDMS nanocomposite, one developed synthesis method is based on solvent swelling of PDMS, like use of water and ethanol. In this work, we synthesized a new Au NPs-PDMS nanocomposite where isopropanol was chosen as solvent to form Au NPs partly embedded into PDMS matrix by means of top-down in-situ reduction. We measured morphological characteristics of the nanocomposite. Optical absorption and PA generation were tested to evaluate performances. The results demonstrate that isopropanol as solvent is beneficial to enhance PA generation in terms of high light absorption (95%) and 6.38 nm of PA amplitude with 6 cm s
^-1
of vibration speed which is higher than ethanol and even 6-fold more than water. These enhanced characteristics support using Au NPs nanocomposite as high-amplitude and high-frequency photoacoustic transuducer material.