[CCoE Notice] (10:30 am US Central Time) Zoom Webinar: Vaporizing Endoskeletal Droplets * 10:30 am, Friday, October 16 * Mark A. Borden * University of Colorado *

[Knudsen, Rachel W]

                                                                             ***** Seminar *****

Department of Electrical and Computer Engineering

Materials Engineering Program

Center for Integrated Bio and Nano Systems

  10:30 a.m., October 16, 2020

Join Zoom Meeting

https://urldefense.com/v3/__https://zoom.us/j/845619943?pwd=QlZvYUV6M2dxNDkvNWxBd3F2YzdJZz09__;!!LkSTlj0I!THDlVVSNWNSld1g63Xzyo1wloMsQkzyQprDostLGdOWMW1adl-s9hGWIW33T0Lbkr6Y$ <https://urldefense.com/v3/__https://zoom.us/j/845619943?pwd=QlZvYUV6M2dxNDkvNWxBd3F2YzdJZz09__;!!LkSTlj0I!RY36v8rc0HmWFLiTTBHvwLA0IazEOlQxdQZC1QwuRSdYLO0ZgFA27Y6PryVryUiq6I-G0w$>



Meeting ID: 845 619 943

Password: 016104



Vaporizing Endoskeletal Droplets


Mark A. Borden



Biomedical Engineering and Mechanical Engineering

University of Colorado, Boulder


Abstract:  Perfluorocarbon droplets have been used extensively as phase-change contrast agents for ultrasound imaging and therapy. This technology has been limited by the tradeoff between vaporizability and colloidal stability. In this seminar, I will introduce a novel droplet design employing a liquid droplet phase and interior solid phase. These “endoskeletal” droplets are made with liquid/solid structures comprising fluorocarbon/fluorocarbon (FC/FC) or fluorocarbon/hydrocarbon (FC/HC). For example, perfluoropentane (n-C5F12) was used as the volatile liquid, and either perlfuorododecane (n-C12F26) or solid normal alkane (ranging from 18 to 24 carbons) was used as the interior solid phase. Vaporization of these droplets was observed over a range of temperatures both optically and acoustically using a clinical ultrasound scanner. The presence of an FC skeleton stabilizes C5F12 against vaporization. Conversely, the presence of an HC skeleton facilitates C5F12 vaporization at a temperature near the melting point of the bulk HC phase. Vaporization temperature could thus be tuned from 23 oC to 45 oC by the choice of HC species. A thermodynamic and molecular dynamics analyses indicated that interfacial melting and mixing of the FC and HC species within the diffuse fluid interface lowered the spinodal and initiated vaporization. On the other hand, for FC/FC endoskeletal droplets, mixing of C12F26 into the C5F12 reinforced intermolecular cohesion and raised the spinodal. These results demonstrate how the interplay between intermolecular forces and entropy can be manipulated to tune vaporization thresholds, a general mechanism that could be used for a large library of droplet components. Of utility, the endoskeletal droplet approach provides both excellent vaporizability and colloidal stability. Future work will exploit these properties for phase-change contrast ultrasound imaging and therapy.


[cid:fd91a09f-9c01-49c5-b316-4bbd568575d3]


Short Bio: Mark Borden is Director of Biomedical Engineering and Professor of Mechanical Engineering at the University of Colorado, Boulder. He received the B.S. in Chemical Engineering from the University of Arizona in 1999 and the Ph.D. in Chemical Engineering from the University of California Davis in 2003. He then worked as a postdoctoral researcher in Biomedical Engineering at UC Davis and visiting scientist in Radiology at the Arizona Cancer Center. He was appointed Assistant Professor of Chemical Engineering at Columbia University in 2007 before moving to CU Boulder in 2010. He currently serves as a technical program committee member of the IEEE International Ultrasonics Symposium and the European Ultrasound Contrast Symposium, and he is a standing member of the NIH Biomaterials and Biointerfaces (BMBI) study section.  His honors include an NSF CAREER Award and the James D. Watson Investigator Award.


Please contact Dr. Cunjiang Yu <cyu13 at Central.UH.EDU> or Jiming Bao (jbao at uh.edu) if you want to meet with the speaker.


If you no longer wish to receive the announcements from the IBNS News Listserver, please email "SIGNOFF IBNSNEWS" in the body of the message (leave subject line empty) to <listserv at listserv.uh.edu<mailto:listserv at listserv.uh.edu>>. The email needs to originate from the email address, which the Listserver sends the announcements to. You can also send an email to <nanomag at uh.edu<mailto:nanomag at uh.edu>> with the request to subscribe to or unsubscribe from the list.






-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://Bug.EGR.UH.EDU/pipermail/engi-dist/attachments/20201015/e1ed4336/attachment-0001.html 
-------------- next part --------------
A non-text attachment was scrubbed...
Name: image.png
Type: image/png
Size: 36016 bytes
Desc: image.png
Url : http://Bug.EGR.UH.EDU/pipermail/engi-dist/attachments/20201015/e1ed4336/attachment-0001.png