Scientists Produce World's First Magnetic Soap

The liquid crystal progression of each surfactant was investigated by the solvent penetration method (i.e. phase cut). A small amount of surfactant was placed on a microscope slide under a coverslip. The slide was mounted on the cover slide and heated until the sample was fluid and completely isotropic. After slow cooling (1.0 °C min-1) to 25 °C, a drop of water was added to the edge of the coverslip. As the water penetrated the surfactant, a concentration gradient was established, from water at one side to pure surfactant at the other, enabling the entire range of mesophases to be observed in the field of view. (Credit: Image courtesy of Institut Laue-Langevin (ILL))


ScienceDaily (Jan. 23, 2012) — Scientists from Bristol University have developed a soap, composed of iron rich salts dissolved in water, that responds to a magnetic field when placed in solution. The soap’s magnetic properties were shown with neutrons at the Institut Laue-Langevin to result from tiny iron-rich clumps that sit within the watery solution. The generation of this property in a fully functional soap could calm concerns over the use of soaps in oil-spill clean ups and revolutionise industrial cleaning products.


Scientists have long been searching for a way to control soaps (or surfactants as they are known in industry) once they are in solution to increase their ability to dissolve oils in water and then remove them from a system. The team at Bristol University have previously worked on soaps sensitive to light, carbon dioxide or changes in pH, temperature or pressure. Their latest breakthrough, reported inAngewandte Chemie, is the world’s first soap sensitive to a magnetic field.

Ionic liquid surfactants, composed mostly of water with some transition metal complexes (heavy metals like iron bound to halides such as bromine or chlorine) have been suggested as potentially controllable by magnets for some time, but it had always been assumed that their metallic centres were too isolated within the solution, preventing the long-range interactions required to be magnetically active.

The team at Bristol, lead by Professor Julian Eastoe produced their magnetic soap by dissolving iron in a range of inert surfactant materials composed of chloride and bromide ions, very similar to those found in everyday mouthwash or fabric conditioner. The addition of the iron creates metallic centres within the soap particles.

To test its properties, the team introduced a magnet to a test tube containing their new soap lying beneath a less dense organic solution. When the magnet was introduced the iron-rich soap overcame both gravity and surface tension between the water and oil, to levitate through the organic solvent and reach the source of the magnetic energy, proving its magnetic properties.

Once the surfactant was developed and shown to be magnetic, Prof Eastoe’s team took it to the Institut Laue-Langevin, the world’s flagship centre for neutron science, and home to the world’s most intense neutron source, to investigate the science behind its remarkable property.

When surfactants are added to water they are known to form tiny clumps (particles called micelles). Scientists at ILL used a technique called “small angle neutron scattering (SANS)” to confirm that it was this clumping of the iron-rich surfactant that brought about its magnetic properties.

Dr Isabelle Grillo, responsible of the Chemistry Laboratories at ILL: “The particles of surfactant in solution are small and thus difficult to see using light but are easily revealed by SANS which we use to investigate the structure and behaviour of all types of materials with typical sizes ranging from the nanometer to the tenth of micrometer.”

The potential applications of magnetic surfactants are huge. Their responsiveness to external stimuli allows a range of properties, such as their electrical conductivity, melting point, the size and shape of aggregates and how readily its dissolves in water to be altered by a simple magnetic on and off switch. Traditionally these factors, which are key to the effective application of soaps in a variety of industrial settings, could only be controlled by adding an electric charge or changing the pH, temperature or pressure of the system, all changes that irreversibly alter the system composition and cost money to remediate.

Its magnetic properties also makes it easier to round up and remove from a system once it has been added, suggesting further applications in environmental clean ups and water treatment. Scientific experiments which require precise control of liquid droplets could also be made easier with the addition of this surfactant and a magnetic field.

Professor Julian Eastoe, University of Bristol: “As most magnets are metals, from a purely scientific point of view these ionic liquid surfactants are highly unusual, making them a particularly interesting discovery. From a commercial point of view, though these exact liquids aren’t yet ready to appear in any household product, by proving that magnetic soaps can be developed, future work can reproduce the same phenomenon in more commercially viable liquids for a range of applications from water treatment to industrial cleaning products.”

Peter Dowding an industrial chemist, not involved in the research: “Any systems which act only when responding to an outside stimulus that has no effect on its composition is a major breakthrough as you can create products which only work when they are needed to. Also the ability to remove the surfactant after it has been added widens the potential applications to environmentally sensitive areas like oil spill clean ups where in the past concerns have been raised.”

Comet Hartley 2 in hyperactive class of its own: CO₂ jets confirmed, new insight into composition, 'excited' rotation

ScienceDaily (June 16, 2011) — Comet Hartley 2, is in a hyperactive class of its own compared to other comets visited by spacecraft, says a University of Maryland-led study published in the June 17 issue of the journal Science.

The comet was visited last fall by NASA's Deep Impact spacecraft during its EPOXI mission. The EPOXI science team's new, in-depth analysis of the images and data taken during the flyby confirms its earlier finding that carbon dioxide is the volatile fuel for Hartley 2's ice-spewing jets.

In-depth analysis of the images and data taken during the flyby of the comet last fall by NASA's Deep Impact spacecraft confirms that carbon dioxide is the volatile fuel for Hartley 2's spectacular ice-spewing jets.

The study also provides several new twists in the unfolding story of this small cometary dynamo including that: (1) the smooth, relatively inactive waist of the peanut shaped comet is likely re-deposited, and thus evolutionary rather than primordial material; (2) Hartley 2 has an 'excited state of rotation' because it spins around one axis, but also tumbles around a different axis; and (3) on its larger, rougher ends, the comet's surface is dotted with glittering, blocky objects that can reach approximately 165 feet (50 meters) high and 260 feet (80 meters) wide.

"Hartley 2 is a hyperactive little comet, spewing out more water than other comets its size," said University of Maryland Astronomer Michael A'Hearn, who is lead author on the Science paper and principal investigator for the EPOXI and Deep Impact missions."When warmed by the sun, dry ice [frozen carbon dioxide] deep in the comet's body turns to gas jetting off the comet and dragging water ice with it.

"Although, Hartley 2 is the only such hyperactive comet visited by a spacecraft, we know of at least a dozen other comets that also are relatively high in activity for their size and which are probably driven by carbon dioxide or carbon monoxide," said A'Hearn, who won the 2008 Kuiper astronomy prize for seminal contributions over his career to the study of comets. "These could represent a separate class of hyperactive comets or just a continuum in comet activity extending from Hartley 2-like comets all the way to the much less active, 'normal' comets that we are more used to seeing."

The EPOXI mission found that the strong activity in water release and carbon dioxide-powered jets did not occur equally in the different regions of the comet. During the spacecraft's flyby of the comet -- with closest approach of 431 miles (694 km) on November 4, 2011 -- carbon dioxide driven jets were seen at the ends of the comet with most occurring at the small end. The water ice particles driven out by these jets created a "snowstorm" through which the spacecraft flew. In the middle region or waist of the comet, water was released as vapor with very little carbon dioxide or ice. The latter findings indicate that material in the waist is likely a product of the activity at the ends of the comet, the researchers say.

"We think the waist is a deposit of material from other parts of the comet, our first evidence of redistribution on a comet," said University of Maryland Astronomy Professor Jessica Sunshine, who is deputy principal investigator for the EPOXI mission. "The most likely mechanism is that some fraction of the dust, icy chunks, and other material coming off the ends of the comet are moving slowly enough to be captured by even the very weak gravity of this small comet. This material then falls back into the lowest point, the middle," said Sunshine, who is principal investigator for Comet Hopper, a mission proposal that is a finalist for selection by NASA as a new planetary mission in the agency's Discovery Program.

The researchers also say that their EPOXI findings indicate the small end of the comet appears to release about twice as much carbon dioxide relative to the amount of water released than does the large end. If true, they write, this difference almost certainly indicates a primordial difference in composition between the two ends, a difference present since this comet's formation.

However, they note that for now this is still a tenuous conclusion. The complex rotation and tumble of Hartley 2 makes it hard to definitively correlate differences in carbon dioxide to water ratios with compositional differences for the two ends of the comet.

"Not only does the total brightness of Hartley 2 vary, but the dust and gas structures in its coma show occasional 'hiccups' over the course of several rotations, phenomena characteristic of a complex rotation state," said study coauthor Tony Farnham, an associate research scientist at the University of Maryland. "These observations suggest that there is something unique about the activity on Hartley 2 that has a major influence on its dynamical state."

In comets, the release of dust and water vapor and the activation of carbon dioxide (and other volatiles) jets are the result of solar heating on the sunward side of a comet. Thus, a complete understanding of how the dual axis rotations affect the amount solar heating that each end of the comet receives is needed in order to determine how much solar heating versus true primordial compositional differences influenced the type and amount of material that is observed streaming out of the comet at both ends.

"Ground based observations can measure, over a much longer period of time, the rotational behavior of Hartley 2, as well as the compositional variations in the extended coma, the cloud of dust and gas surrounding the body of the comet," said coauthor Lori Feaga, an assistant research scientist at the University of Maryland. "Several other research groups have made such observations of the comet, and their finding will assist us in jointly disentangling the underlying cause of Hartley 2's heterogeneity."

The study notes that another EPOXI discovery is that on the knobby ends of Hartley 2, particularly the smaller end, the surface terrain is dotted with block-like, shiny objects, some as big as a block-long, 16-story-tall building -- tops of 165 feet (50 meters) high and 260 feet (80 meters) wide. The study says the objects appear to be two to three times more reflective than the surface average.

"These are spectacular features, but at this point we don't know whether these are deposits or growths, or something else," said Sunshine.

Deep Impact on Comet Science

Comets are fundamental building blocks of the giant planets and may have been an important source by which water and organics -- the essentials of life as we know it -- came to Earth.

On its EPOXI mission the Deep Impact spacecraft flew by Hartley 2 on Nov. 4, 2010, just a few weeks after the comet had passed within 11 million miles of Earth. Equipped with two telescopes with digital color cameras and a near-infrared spectrometer, the spacecraft beamed back more than a million images and spectra of Hartley 2 during an imaging period encompassing 2 months on approach of the comet and 3 weeks on departure.

With its EPOXI mission data, the Deep Impact spacecraft added to its extensive scientific legacy. Launched in January 2005, the spacecraft made history and world-wide headlines when it smashed a probe into comet Tempel 1 on July 4th of that year. Following the conclusion of that mission, a Maryland-led team of scientists won approval from NASA to fly the Deep Impact spacecraft to a second comet as part of an extended mission named EPOXI (Extrasolar Planet Observation and Deep Impact Extended Investigation).

The spacecraft remains in excellent condition, but has no fuel for future travels. Use of the spacecraft as an orbiting observatory remains possible.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Maryland.

Journal Reference:

A'Hearn et al. EPOXI at Comet Hartley 2. Science, 2011; 332 (6036): 1396-1400 DOI: 10.1126/science.1204054

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here

Comet Hartley 2 in hyperactive class of its own: CO₂ jets confirmed, new insight into composition, 'excited' rotation

ScienceDaily (June 16, 2011) — Comet Hartley 2, is in a hyperactive class of its own compared to other comets visited by spacecraft, says a University of Maryland-led study published in the June 17 issue of the journal Science.

The comet was visited last fall by NASA's Deep Impact spacecraft during its EPOXI mission. The EPOXI science team's new, in-depth analysis of the images and data taken during the flyby confirms its earlier finding that carbon dioxide is the volatile fuel for Hartley 2's ice-spewing jets.

In-depth analysis of the images and data taken during the flyby of the comet last fall by NASA's Deep Impact spacecraft confirms that carbon dioxide is the volatile fuel for Hartley 2's spectacular ice-spewing jets.

The study also provides several new twists in the unfolding story of this small cometary dynamo including that: (1) the smooth, relatively inactive waist of the peanut shaped comet is likely re-deposited, and thus evolutionary rather than primordial material; (2) Hartley 2 has an 'excited state of rotation' because it spins around one axis, but also tumbles around a different axis; and (3) on its larger, rougher ends, the comet's surface is dotted with glittering, blocky objects that can reach approximately 165 feet (50 meters) high and 260 feet (80 meters) wide.

"Hartley 2 is a hyperactive little comet, spewing out more water than other comets its size," said University of Maryland Astronomer Michael A'Hearn, who is lead author on the Science paper and principal investigator for the EPOXI and Deep Impact missions."When warmed by the sun, dry ice [frozen carbon dioxide] deep in the comet's body turns to gas jetting off the comet and dragging water ice with it.

"Although, Hartley 2 is the only such hyperactive comet visited by a spacecraft, we know of at least a dozen other comets that also are relatively high in activity for their size and which are probably driven by carbon dioxide or carbon monoxide," said A'Hearn, who won the 2008 Kuiper astronomy prize for seminal contributions over his career to the study of comets. "These could represent a separate class of hyperactive comets or just a continuum in comet activity extending from Hartley 2-like comets all the way to the much less active, 'normal' comets that we are more used to seeing."

The EPOXI mission found that the strong activity in water release and carbon dioxide-powered jets did not occur equally in the different regions of the comet. During the spacecraft's flyby of the comet -- with closest approach of 431 miles (694 km) on November 4, 2011 -- carbon dioxide driven jets were seen at the ends of the comet with most occurring at the small end. The water ice particles driven out by these jets created a "snowstorm" through which the spacecraft flew. In the middle region or waist of the comet, water was released as vapor with very little carbon dioxide or ice. The latter findings indicate that material in the waist is likely a product of the activity at the ends of the comet, the researchers say.

"We think the waist is a deposit of material from other parts of the comet, our first evidence of redistribution on a comet," said University of Maryland Astronomy Professor Jessica Sunshine, who is deputy principal investigator for the EPOXI mission. "The most likely mechanism is that some fraction of the dust, icy chunks, and other material coming off the ends of the comet are moving slowly enough to be captured by even the very weak gravity of this small comet. This material then falls back into the lowest point, the middle," said Sunshine, who is principal investigator for Comet Hopper, a mission proposal that is a finalist for selection by NASA as a new planetary mission in the agency's Discovery Program.

The researchers also say that their EPOXI findings indicate the small end of the comet appears to release about twice as much carbon dioxide relative to the amount of water released than does the large end. If true, they write, this difference almost certainly indicates a primordial difference in composition between the two ends, a difference present since this comet's formation.

However, they note that for now this is still a tenuous conclusion. The complex rotation and tumble of Hartley 2 makes it hard to definitively correlate differences in carbon dioxide to water ratios with compositional differences for the two ends of the comet.

"Not only does the total brightness of Hartley 2 vary, but the dust and gas structures in its coma show occasional 'hiccups' over the course of several rotations, phenomena characteristic of a complex rotation state," said study coauthor Tony Farnham, an associate research scientist at the University of Maryland. "These observations suggest that there is something unique about the activity on Hartley 2 that has a major influence on its dynamical state."

In comets, the release of dust and water vapor and the activation of carbon dioxide (and other volatiles) jets are the result of solar heating on the sunward side of a comet. Thus, a complete understanding of how the dual axis rotations affect the amount solar heating that each end of the comet receives is needed in order to determine how much solar heating versus true primordial compositional differences influenced the type and amount of material that is observed streaming out of the comet at both ends.

"Ground based observations can measure, over a much longer period of time, the rotational behavior of Hartley 2, as well as the compositional variations in the extended coma, the cloud of dust and gas surrounding the body of the comet," said coauthor Lori Feaga, an assistant research scientist at the University of Maryland. "Several other research groups have made such observations of the comet, and their finding will assist us in jointly disentangling the underlying cause of Hartley 2's heterogeneity."

The study notes that another EPOXI discovery is that on the knobby ends of Hartley 2, particularly the smaller end, the surface terrain is dotted with block-like, shiny objects, some as big as a block-long, 16-story-tall building -- tops of 165 feet (50 meters) high and 260 feet (80 meters) wide. The study says the objects appear to be two to three times more reflective than the surface average.

"These are spectacular features, but at this point we don't know whether these are deposits or growths, or something else," said Sunshine.

Deep Impact on Comet Science

Comets are fundamental building blocks of the giant planets and may have been an important source by which water and organics -- the essentials of life as we know it -- came to Earth.

On its EPOXI mission the Deep Impact spacecraft flew by Hartley 2 on Nov. 4, 2010, just a few weeks after the comet had passed within 11 million miles of Earth. Equipped with two telescopes with digital color cameras and a near-infrared spectrometer, the spacecraft beamed back more than a million images and spectra of Hartley 2 during an imaging period encompassing 2 months on approach of the comet and 3 weeks on departure.

With its EPOXI mission data, the Deep Impact spacecraft added to its extensive scientific legacy. Launched in January 2005, the spacecraft made history and world-wide headlines when it smashed a probe into comet Tempel 1 on July 4th of that year. Following the conclusion of that mission, a Maryland-led team of scientists won approval from NASA to fly the Deep Impact spacecraft to a second comet as part of an extended mission named EPOXI (Extrasolar Planet Observation and Deep Impact Extended Investigation).

The spacecraft remains in excellent condition, but has no fuel for future travels. Use of the spacecraft as an orbiting observatory remains possible.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by University of Maryland.

Journal Reference:

A'Hearn et al. EPOXI at Comet Hartley 2. Science, 2011; 332 (6036): 1396-1400 DOI: 10.1126/science.1204054

Note: If no author is given, the source is cited instead.

Disclaimer: Views expressed in this article do not necessarily reflect those of ScienceDaily or its staff.

View the original article here