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 August 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 August 30, 2014).

Share This




More Matter & Energy News

Saturday, August 30, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Australian Airlines Relax Phone Ban Too

Australian Airlines Relax Phone Ban Too

Reuters - Business Video Online (Aug. 26, 2014) Qantas and Virgin say passengers can use their smartphones and tablets throughout flights after a regulator relaxed a ban on electronic devices during take-off and landing. As Hayley Platt reports the move comes as the two domestic rivals are expected to post annual net losses later this week. Video provided by Reuters
Powered by NewsLook.com
Hurricane Marie Brings Big Waves to California Coast

Hurricane Marie Brings Big Waves to California Coast

Reuters - US Online Video (Aug. 26, 2014) Huge waves generated by Hurricane Marie hit the Southern California coast. Rough Cut (no reporter narration). Video provided by Reuters
Powered by NewsLook.com
Chinese Researchers Might Be Creating Supersonic Submarine

Chinese Researchers Might Be Creating Supersonic Submarine

Newsy (Aug. 26, 2014) Chinese researchers have expanded on Cold War-era tech and are closer to building a submarine that could reach the speed of sound. Video provided by Newsy
Powered by NewsLook.com
Breakingviews: India Coal Strained by Supreme Court Ruling

Breakingviews: India Coal Strained by Supreme Court Ruling

Reuters - Business Video Online (Aug. 26, 2014) An acute coal shortage is likely to be aggravated as India's supreme court declared government coal allocations illegal, says Breakingviews' Peter Thal Larsen. Video provided by Reuters
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