Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Goldilocks Principle Wrong for Particle Assembly: Too Hot & Too Cold Is Just Right

21.10.2014

Microscopic particles that bind under low temperatures will melt as temperatures rise to moderate levels, but re-connect under hotter conditions, a team of New York University scientists has found. Their discovery points to new ways to create “smart materials,” cutting-edge materials that adapt to their environment by taking new forms, and to sharpen the detail of 3D printing.

“These findings show the potential to engineer the properties of materials using not only temperature, but also by employing a range of methods to manipulate the smallest of particles,” explains Lang Feng, the study’s lead author and an NYU doctoral student at the time it was conducted.


Image courtesy of Lang Feng.

Microscopic particles that bind under low temperatures (blue: bottom left) will melt as temperatures rise to moderate levels (green: center), but re-connect under hotter conditions (red: top right), a team of NYU scientists has found. Their discovery points to new ways to create “smart materials,” cutting-edge materials that adapt to their environment by taking new forms, and to sharpen the detail of 3D printing.

The research, which appears in the journal Nature Materials, reveals that the well-known Goldilocks Principle, which posits that success is found in the middle rather than at extremes, doesn’t necessarily apply to the smallest of particles.

The study focuses on polymers and colloids—particles as small as one-billionth and one-millionth of a meter in size, respectively.

These materials, and how they form, are of notable interest to scientists because they are the basis for an array of consumer products. For instance, colloidal dispersions comprise such everyday items as paint, milk, gelatin, glass, and porcelain and for advanced engineering such as steering light in photonics.

By better understanding polymer and colloidal formation, scientists have the potential to harness these particles and create new and enhanced materials—possibilities that are now largely untapped or are in relatively rudimentary form.

In the Nature Materials study, the researchers examined polymers and larger colloidal crystals at temperatures ranging from room temperature to 85 degrees C.

At room temperature, the polymers act as a gas bumping against the larger particles and applying a pressure that forces them together once the distance between the particles is too small to admit a polymer. In fact, the colloids form a crystal using this process known as the depletion interaction—an attractive entropic force, which is a dynamic that results from maximizing the random motion of the polymers and the range of space they have the freedom to explore.

As usual, the crystals melt on heating, but, unexpectedly, on heating further they re-solidify. The new solid is a Jello-like substance, with the polymers adhering to the colloids and gluing them together. This solid is much softer, more pliable and more open than the crystal.

This result, the researchers observe, reflects enthalpic attraction—the adhesive energy generated by the higher temperatures and stimulating bonding between the particles. By contrast, at the mid-level temperatures, conditions were too warm to accommodate entropic force, yet too cool to bring about enthalpic attraction.

Lang, now a senior researcher at ExxonMobil, observes that the finding may have potential in 3D printing. Currently, this technology can create 3D structures from two-dimensional layers. However, the resulting structures are relatively rudimentary in nature. By enhancing how particles are manipulated at the microscopic level, these machines could begin creating objects that are more detailed, and realistic, than is currently possible.

This work is supported partially by the National Science Foundation’s MRSEC Program (DMR-0820341), NASA (NNX08AK04G), and the Department of Energy (DE-SC0007991).

Contact Information

James Devitt
Deputy Director for Media Relations
james.devitt@nyu.edu
Phone: 212-998-6808

James Devitt | newswise
Further information:
http://www.nyu.edu

More articles from Physics and Astronomy:

nachricht NASA's SDO sees partial eclipse in space
29.05.2017 | NASA/Goddard Space Flight Center

nachricht Strathclyde-led research develops world's highest gain high-power laser amplifier
29.05.2017 | University of Strathclyde

All articles from Physics and Astronomy >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Strathclyde-led research develops world's highest gain high-power laser amplifier

The world's highest gain high power laser amplifier - by many orders of magnitude - has been developed in research led at the University of Strathclyde.

The researchers demonstrated the feasibility of using plasma to amplify short laser pulses of picojoule-level energy up to 100 millijoules, which is a 'gain'...

Im Focus: Can the immune system be boosted against Staphylococcus aureus by delivery of messenger RNA?

Staphylococcus aureus is a feared pathogen (MRSA, multi-resistant S. aureus) due to frequent resistances against many antibiotics, especially in hospital infections. Researchers at the Paul-Ehrlich-Institut have identified immunological processes that prevent a successful immune response directed against the pathogenic agent. The delivery of bacterial proteins with RNA adjuvant or messenger RNA (mRNA) into immune cells allows the re-direction of the immune response towards an active defense against S. aureus. This could be of significant importance for the development of an effective vaccine. PLOS Pathogens has published these research results online on 25 May 2017.

Staphylococcus aureus (S. aureus) is a bacterium that colonizes by far more than half of the skin and the mucosa of adults, usually without causing infections....

Im Focus: A quantum walk of photons

Physicists from the University of Würzburg are capable of generating identical looking single light particles at the push of a button. Two new studies now demonstrate the potential this method holds.

The quantum computer has fuelled the imagination of scientists for decades: It is based on fundamentally different phenomena than a conventional computer....

Im Focus: Turmoil in sluggish electrons’ existence

An international team of physicists has monitored the scattering behaviour of electrons in a non-conducting material in real-time. Their insights could be beneficial for radiotherapy.

We can refer to electrons in non-conducting materials as ‘sluggish’. Typically, they remain fixed in a location, deep inside an atomic composite. It is hence...

Im Focus: Wafer-thin Magnetic Materials Developed for Future Quantum Technologies

Two-dimensional magnetic structures are regarded as a promising material for new types of data storage, since the magnetic properties of individual molecular building blocks can be investigated and modified. For the first time, researchers have now produced a wafer-thin ferrimagnet, in which molecules with different magnetic centers arrange themselves on a gold surface to form a checkerboard pattern. Scientists at the Swiss Nanoscience Institute at the University of Basel and the Paul Scherrer Institute published their findings in the journal Nature Communications.

Ferrimagnets are composed of two centers which are magnetized at different strengths and point in opposing directions. Two-dimensional, quasi-flat ferrimagnets...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Marine Conservation: IASS Contributes to UN Ocean Conference in New York on 5-9 June

24.05.2017 | Event News

AWK Aachen Machine Tool Colloquium 2017: Internet of Production for Agile Enterprises

23.05.2017 | Event News

Dortmund MST Conference presents Individualized Healthcare Solutions with micro and nanotechnology

22.05.2017 | Event News

 
Latest News

New photocatalyst speeds up the conversion of carbon dioxide into chemical resources

29.05.2017 | Life Sciences

NASA's SDO sees partial eclipse in space

29.05.2017 | Physics and Astronomy

New drug reduces transplant and mortality rates significantly in patients with hepatitis C

29.05.2017 | Statistics

VideoLinks
B2B-VideoLinks
More VideoLinks >>>