Anti-clumping strategy for nanoparticles

October 16, 2015, Springer

Nanoparticles are ubiquitous in industrial applications ranging from drug delivery and biomedical diagnostics to developing hydrophobic surfaces, lubricant additives and enhanced oil recovery solutions in petroleum fields. For such nanoparticles to be effective, they need to remain well dispersed into the fluid surrounding them. In a study published in EPJ B, Brazilian physicists identified the conditions that lead to instability of nanoparticles and producing aggregates. This happens when the electric force on their surface no longer balances by the sum of the attractive or repulsive forces between nanoparticles. These findings were recently published by Lucas de Lara from the Centre for Natural and Human Sciences, at the University Federal of ABC (UFABC) in Santo André, SP, Brazil and colleagues.

The authors studied silica that do not react with their surroundings in a solution containing two types of salts, table salt and . They then attached an ending to the nanoparticles, a process called functionalisation. Featuring endings that are hydrophilic or hydrophobic can help nanoparticles remain dispersed.

They then varied the temperature and salt concentration and monitored the ion dispersion in the salty solution. In some cases, they observed the accumulation of ions around nanoparticles, leading to the formation of an electric double-layer around the nanoparticles in otherwise overall electrically neutral nanoparticle suspensions.

De Lara and colleagues then determined the factor influencing the stability of such nanoparticles in solutions. Their simulations suggest that the instability of functionalised nanoparticles dispersion in brine depends on several factors preceding their aggregation. The "culprits" include the formation of an electric double layer - observed to be greater for calcium chloride than for table salt - and the narrowing of that double layer. In addition, the considerable variation in the interface tension followed by a steep increase in ion mobility also contribute to instability. The group's findings on overall neutral nanoparticles are in line with previous work with electrically charged nanoparticles.

Explore further: Tuning polymer interpenetration

More information: Lucas S. de Lara et al. The stability and interfacial properties of functionalized silica nanoparticles dispersed in brine studied by molecular dynamics, The European Physical Journal B (2015). DOI: 10.1140/epjb/e2015-60543-1

Related Stories

Tuning polymer interpenetration

September 17, 2015

Polymer nanocomposites are used in a wide range of applications, from automobile parts and tires to high-tech electronics and solar cells.

Doping crystals of nanocrystals

September 24, 2015

Silicon semiconductors form the basis of all modern electronics and microprocessors. Crucial to these applications is the ability to 'dope' the semiconductor; which is to say, by controllably adding impurity atoms to a semiconductor, ...

How to count nanoparticles

October 11, 2011

Nanoparticles of a substance can be counted and the size distribution can be determined by dispersing the nanoparticles into a gas. But some nanoparticles tend to aggregate when the surrounding conditions change. Scientists ...

Recommended for you

Scientists have a new way to gauge the growth of nanowires

March 19, 2018

In a new study, researchers from the U.S. Department of Energy's (DOE) Argonne and Brookhaven National Laboratories observed the formation of two kinds of defects in individual nanowires, which are smaller in diameter than ...

Rubbery carbon aerogels greatly expand applications

March 19, 2018

Researchers have designed carbon aerogels that can be reversibly stretched to more than three times their original length, displaying elasticity similar to that of a rubber band. By adding reversible stretchability to aerogels' ...

Plasmons triggered in nanotube quantum wells

March 16, 2018

A novel quantum effect observed in a carbon nanotube film could lead to the development of unique lasers and other optoelectronic devices, according to scientists at Rice University and Tokyo Metropolitan University.

Zero field switching (ZFS) effect in a nanomagnetic device

March 16, 2018

An unexpected phenomenon known as zero field switching (ZFS) could lead to smaller, lower-power memory and computing devices than presently possible. The image shows a layering of platinum (Pt), tungsten (W), and a cobalt-iron-boron ...

Imaging technique pulls plasmon data together

March 16, 2018

Rice University scientists have developed a novel technique to view a field of plasmonic nanoparticles simultaneously to learn how their differences change their reactivity.


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.