title: Ultrafast vapourization dynamics of laser-activated polymeric microcapsules.
abstract: Precision control of vapourization, both in space and time, has many potential applications; however, the physical mechanisms underlying controlled boiling are not well understood. The reason is the combined microscopic length scales and ultrashort timescales associated with the initiation and subsequent dynamical behaviour of the vapour bubbles formed. Here we study the nanoseconds vapour bubble dynamics of laser-heated single oil-filled microcapsules using coupled optical and acoustic detection. Pulsed laser excitation leads to vapour formation and collapse, and a simple physical model captures the observed radial dynamics and resulting acoustic pressures. Continuous wave laser excitation leads to a sequence of vapourization/condensation cycles, the result of absorbing microcapsule fragments moving in and out of the laser beam. A model incorporating thermal diffusion from the capsule shell into the oil core and surrounding water reveals the mechanisms behind the onset of vapourization. Excellent agreement is observed between the modelled dynamics and experiment.
authors.affiliation: Physics of Fluids Group, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Lajoinie
authors.affiliation: Physics of Fluids Group, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Erik
authors.initials: E
authors.lastname: Gelderblom
authors.affiliation: Philips Research Laboratories Europe, High Tech Campus 11, 5656 AE Eindhoven, The Netherlands.
authors.forename: Ceciel
authors.initials: C
authors.lastname: Chlon
authors.affiliation: Philips Research Laboratories Europe, High Tech Campus 11, 5656 AE Eindhoven, The Netherlands.
authors.forename: Marcel
authors.initials: M
authors.lastname: Böhmer
authors.affiliation: Biomedical Photonic Imaging Group, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Wiendelt
authors.initials: W
authors.lastname: Steenbergen
authors.affiliation: Biomedical Engineering, Thoraxcenter, Erasmus MC, P.O. Box 2040, 3000 CA Rotterdam, The Netherlands.
authors.forename: Nico
authors.initials: N
authors.lastname: de Jong
authors.affiliation: Biomedical Photonic Imaging Group, MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Srirang
authors.initials: S
authors.lastname: Manohar
authors.affiliation: Physics of Fluids Group, MESA+ Institute for Nanotechnology and MIRA Institute for Biomedical Technology and Technical Medicine, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors.forename: Michel
authors.initials: M
authors.lastname: Versluis