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Dive into the research topics where Colin Kelsey is active.

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Featured researches published by Colin Kelsey.


Nano Letters | 2017

Continuous In-Flight Synthesis for On-Demand Delivery of Ligand-Free Colloidal Gold Nanoparticles

Paul Maguire; David Rutherford; Manuel Macias-Montero; Charles Mahony; Colin Kelsey; Mark Tweedie; Fatima Perez-Martin; Harold McQuaid; Declan A. Diver; Davide Mariotti

We demonstrate an entirely new method of nanoparticle chemical synthesis based on liquid droplet irradiation with ultralow (<0.1 eV) energy electrons. While nanoparticle formation via high energy radiolysis or transmission electron microscopy-based electron bombardment is well-understood, we have developed a source of electrons with energies close to thermal which leads to a number of important and unique benefits. The charged species, including the growing nanoparticles, are held in an ultrathin surface reaction zone which enables extremely rapid precursor reduction. In a proof-of-principle demonstration, we obtain small-diameter Au nanoparticles (∼4 nm) with tight control of polydispersity, in under 150 μs. The precursor was almost completely reduced in this period, and the resultant nanoparticles were water-soluble and free of surfactant or additional ligand chemistry. Nanoparticle synthesis rates within the droplets were many orders of magnitude greater than equivalent rates reported for radiolysis, electron beam irradiation, or colloidal chemical synthesis where reaction times vary from seconds to hours. In our device, a stream of precursor loaded microdroplets, ∼15 μm in diameter, were transported rapidly through a cold atmospheric pressure plasma with a high charge concentration. A high electron flux, electron and nanoparticle confinement at the surface of the droplet, and the picoliter reactor volume are thought to be responsible for the remarkable enhancement in nanoparticle synthesis rates. While this approach exhibits considerable potential for scale-up of synthesis rates, it also offers the more immediate prospect of continuous on-demand delivery of high-quality nanomaterials directly to their point of use by avoiding the necessity of collection, recovery, and purification. A range of new applications can be envisaged, from theranostics and biomedical imaging in tissue to inline catalyst production for pollution remediation in automobiles.


international conference on plasma science | 2012

Chemistry and new applications of plasmas created in conducting liquids

Colin Kelsey; Ahmad Mashal; Lucie Nemcova; W. G. Graham

Summary form only given. There are many current and potential applications for plasmas created in conducting liquids and particularly in isotonic saline solution1. As a result there is interest in the physics of the plasma production, how it is sustained, the type of plasmas produced, their parameters and the subsequent plasma produced chemistry. There have been a number of studies of various topics in this list2 however the full characterisation of the plasma has been hampered since the plasma formation process is not reproducible and many conventional plasma diagnostic techniques cannot, as yet, be applied in the liquid environment.


international conference on plasma science | 2012

Characterisation of plasmas created in conducting liquids

Colin Kelsey; W. G. Graham

Summary form only given. There are many current and potential applications for plasmas created in conducting liquids and particularly in isotonic saline solution1. As a result there is interest in the physics of the plasma production, how it is sustained, the type of plasmas produced, their parameters and the subsequent plasma produced chemistry. There have been a number of studies of various topics in this list2 however the full characterisation of the plasma has been hampered since the plasma formation process is not reproducible and many conventional plasma diagnostic techniques cannot, as yet, be applied in the liquid environment.


Small | 2014

A New Mechanism for Hydroxyl Radical Production in Irradiated Nanoparticle Solutions

Cécile Sicard-Roselli; Emilie Brun; Manon Gilles; G. Baldacchino; Colin Kelsey; Harold McQuaid; Chris Polin; Nathan Wardlow; Frederick Currell


Bulletin of the American Physical Society | 2016

Plasma charging and electron-based reactions at the plasma-liquid interface of an isolated liquid droplet

Paul Maguire; Charles Mahony; Colin Kelsey; David Rutherford; Davide Mariotti; Declan A. Diver


Bulletin of the American Physical Society | 2016

Generation and remote delivery of plasma activated species

Paul Maguire; Charles Mahony; Colin Kelsey; David Rutherford; Davide Mariotti; Manuel Macias-Montero; Fatima Perez-Martin; Declan A. Diver


Bulletin of the American Physical Society | 2015

Gas phase microreaction: nanomaterials synthesis via plasma exposure of liquid droplets

Paul Maguire; Charles Mahony; Colin Kelsey; Neil Hamilton; Sadegh Askari; Manuel Macias-Montero; Declan A. Diver; Davide Mariotti


Bulletin of the American Physical Society | 2015

Controlled Microdroplet Transport {\&} Charging in an Atmospheric Pressure Microplasma

Colin Kelsey; Paul Maguire; Charles Mahony; Neil Hamilton; Davide Mariotti; David Rutherford; David L. McDowell; F 'atima P 'erez-Mart 'In; Euan Bennet; Hugh Potts; Declan A. Diver


Bulletin of the American Physical Society | 2015

Precision charging of microparticles in plasma via the Rayleigh instability for evaporating charged liquid droplets

Euan Bennet; Charles Mahony; Hugh Potts; Paul Everest; David Rutherford; Sadegh Askari; Colin Kelsey; Fatima Perez-Martin; Neil Hamilton; David A. McDowell; Davide Mariotti; Paul Maguire; Declan A. Diver


Bulletin of the American Physical Society | 2015

Uniform dose atmospheric pressure microplasma exposure of individual bacterial cells

David Rutherford; Charles Mahony; Sarah Spence; Fatima Perez-Martin; Colin Kelsey; Neil Hamilton; Declan A. Diver; Euan Bennet; Hugh Potts; Davide Mariotti; David L. McDowell; Paul Maguire

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W. G. Graham

Queen's University Belfast

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Ahmad Mashal

Queen's University Belfast

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Bill Graham

Queen's University Belfast

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Harold McQuaid

Queen's University Belfast

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David L. McDowell

Georgia Institute of Technology

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Emilie Brun

University of Paris-Sud

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