title: Nano-structural characteristics of carbon nanotube-polymer composite films for high-amplitude optoacoustic generation.
abstract: We demonstrate nano-structural characteristics of carbon nanotube (CNT)-polydimethylsiloxane (PDMS) composite films that can be used as highly efficient and robust ultrasound transmitters for diagnostic and therapeutic applications. An inherent architecture of the nano-composite provides unique thermal, optical, and mechanical properties that are accommodated not just for efficient energy conversion but also for extraordinary robustness against pulsed laser ablation. First, we explain a thermoacoustic transfer mechanism within the nano-composite. CNT morphologies are examined to determine a suitable arrangement for heat transfer to the surrounding PDMS. Next, we introduce an approach to enhance optical extinction of the composite films, which uses shadowed deposition of a thin Au layer through an as-grown CNT network. Finally, the transmitter robustness is quantified in terms of laser-induced damage threshold. This reveals that the CNT-PDMS films can withstand an order-of-magnitude higher optical fluence (and extinction) than a Cr film used as a reference. Such robustness is crucial to increase the maximum-available optical energy for optoacoustic excitation and pressure generation. All of these structure-originated characteristics manifest the CNT-PDMS composite films as excellent optoacoustic transmitters for high-amplitude and high-frequency ultrasound generation.
authors.affiliation: School of Electronic and Electrical Engineering, Sungkyunkwan University, Suwon 440-746, Republic of Korea.
authors.forename: Hyoung Won
authors.initials: HW
authors.lastname: Baac
authors.forename: Jong G
authors.initials: JG
authors.lastname: Ok
authors.forename: Taehwa
authors.initials: T
authors.lastname: Lee
authors.forename: L Jay
authors.initials: LJ
authors.lastname: Guo
mesh_terms: D004129:Dimethylpolysiloxanes / Q000737:chemistry; D006046:Gold / Q000737:chemistry; D007834:Lasers; D049329:Nanostructures / Q000737:chemistry*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D061088:Photoacoustic Techniques; D011108:Polymers / Q000737:chemistry*; D013696:Temperature
chemical_list: D004129:Dimethylpolysiloxanes; D037742:Nanotubes, Carbon; D011108:Polymers; C013830:baysilon; D006046:Gold