Featured Research

from universities, journals, and other organizations

Researchers model macroscale plasmonic convection to control fluid and particle motion

Date:
January 22, 2014
Source:
University of Illinois College of Engineering
Summary:
Researchers have developed a new theoretical model that explains macroscale fluid convection induced by plasmonic (metal) nanostructures. This work is the first to establish both theoretically and experimentally that micron/s fluid velocities can be generated using a plasmonic architecture, and provides important insight into the flows affecting particle dynamics in plasmonic optical trapping experiments.

Depiction of the fluid convection (arrows) overlaid on the background temperature distribution produced by the BNAs and ITO. Inset shows the BNA geometry with a (false color) scanning electron microscope image of a single bowtie; scale bar is 200 nm.
Credit: Image courtesy of University of Illinois College of Engineering

Researchers at Illinois have developed a new theoretical model that explains macroscale fluid convection induced by plasmonic (metal) nanostructures. Their model demonstrates the experimentally observed convection velocities of the order of micrometers per second for an array of gold bowtie nanoantennas (BNAs) coupled to an optically absorptive indium-tin-oxide (ITO) substrate.

Depiction of the fluid convection (arrows) overlaid on the background temperature distribution produced by the BNAs and ITO. Inset shows the BNA geometry with a (false color) scanning electron microscope image of a single bowtie; scale bar is 200 nm.

"Plasmonics offers numerous opportunities to control fluid motion using light absorption," explained Kimani Toussaint, an associate professor in the Department of Mechanical Science and Engineering (MechSE). "The common understanding in the literature is that the observation of micron/s particle motion in plasmonic tweezers experiments can be accurately modeled if one increased the number of nanostructures -- for example, nanoantennas -- in the array. We showed that this alone would not explain the phenomena. The ITO is the critical piece to the puzzle,"

"This first collaborative study opens doors to investigate phenomena such as particle separation, nanobubble generation, and optical switching. Computations provide a complementary approach to laboratory observations," said MechSE emeritus professor Pratap Vanka, a co-author of the study. Results of the plasmon-induced convection research, with electrical and computer engineering graduate students Brian Roxworthy and Abdul Bhuiya, have been published in the January issue of Nature Communications.

"This work is the first to establish both theoretically and experimentally that micron/s fluid velocities can be generated using a plasmonic architecture, and provides important insight into the flows affecting particle dynamics in plasmonic optical trapping experiments. And our system can be integrated into microfluidic environments to enable greater dexterity in fluid handling and temperature control," Roxworthy said.

The model uses a set of coupled partial differential equations describing the electromagnetic, heat-transfer, and fluid mechanics phenomena, which is solved using COMSOL Multiphysics, a commercial software package. In the study, gold BNAs are illuminated by 2.5 mW of laser light at three different wavelengths, whereby each wavelength corresponds to be on-, near-, or off-resonance with respect to the plasmon resonance wavelength of the BNAs. A solution containing dielectric, spherical particles with diameters of 1 to 20 microns are placed on the BNAs and used to trace the generated fluid flows.

The development of the model led the researchers to several important conclusions. It allowed them to understand the high-velocity particle motion observed in experiments with plasmonic tweezers, and they realized that inclusion of an ITO layer is critical in distributing the thermal energy created by the BNAs -- a fact that has previously been overlooked. Additionally, they found that the ITO alone could be used as a simple, alternative route to achieving fluid convection in lab-on-a-chip environments. The researchers also observed that the plasmonic array alters absorption in the ITO, causing a deviation from Beer-Lambert absorption.


Story Source:

The above story is based on materials provided by University of Illinois College of Engineering. Note: Materials may be edited for content and length.


Journal Reference:

  1. Brian J. Roxworthy, Abdul M. Bhuiya, Surya P. Vanka, Kimani C. Toussaint. Understanding and controlling plasmon-induced convection. Nature Communications, 2014; 5 DOI: 10.1038/ncomms4173

Cite This Page:

University of Illinois College of Engineering. "Researchers model macroscale plasmonic convection to control fluid and particle motion." ScienceDaily. ScienceDaily, 22 January 2014. <www.sciencedaily.com/releases/2014/01/140122112715.htm>.
University of Illinois College of Engineering. (2014, January 22). Researchers model macroscale plasmonic convection to control fluid and particle motion. ScienceDaily. Retrieved July 30, 2014 from www.sciencedaily.com/releases/2014/01/140122112715.htm
University of Illinois College of Engineering. "Researchers model macroscale plasmonic convection to control fluid and particle motion." ScienceDaily. www.sciencedaily.com/releases/2014/01/140122112715.htm (accessed July 30, 2014).

Share This




More Matter & Energy News

Wednesday, July 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Britain Testing Driverless Cars on Roadways

Britain Testing Driverless Cars on Roadways

AP (July 30, 2014) British officials said on Wednesday that driverless cars will be tested on roads in as many as three cities in a trial program set to begin in January. Officials said the tests will last up to three years. (July 30) Video provided by AP
Powered by NewsLook.com
China's Drone King Says the Revolution Depends on Regulators

China's Drone King Says the Revolution Depends on Regulators

Reuters - Business Video Online (July 30, 2014) Comparing his current crop of drones to early personal computers, DJI founder Frank Wang says the industry is poised for a growth surge - assuming regulators in more markets clear it for takeoff. Jon Gordon reports. Video provided by Reuters
Powered by NewsLook.com
3Doodler Bring 3-D Printing to Your Hand

3Doodler Bring 3-D Printing to Your Hand

AP (July 30, 2014) 3-D printing is a cool technology, but it's not exactly a hands-on way to make things. Enter the 3Doodler: the pen that turns you into the 3-D printer. AP technology writer Peter Svensson takes a closer look. (July 30) Video provided by AP
Powered by NewsLook.com
Climate Change Could Cost Billions, According To White House

Climate Change Could Cost Billions, According To White House

Newsy (July 29, 2014) A report from the White House warns not curbing greenhouse gas emissions could cost the U.S. billions. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile: iPhone Android Web
Follow: Facebook Twitter Google+
Subscribe: RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins