The science of syrup and traffic jams
An international group of scientists from the UK, Germany, and Australia has discovered the reason why syrup is so sticky by comparing it with traffic jams. When salts or sugars are added to water, the resulting mixture is very ‘sticky’ and flows with great difficulty or – to use the scientific term – it has a high viscosity. This effect is probably most familiar in mixtures of sugars and water such as in syrup and honey.
A debate has been raging for decades as to the scientific reason why things like honey are so sticky. The consensus had been that sugar and salt molecules in water would bind to the water molecules and thereby alter the structure of water. So-called structure inducers (with the beautiful scientific name ‘kosmotropes’) would make liquid water more ice-like and thus stickier... Unfortunately, work by a Dutch group threw a spanner in the works by suggesting that no such structure-inducing effect exists (DOI: 10.1126/science.1084801) leaving chemists and physicists at a loss how to explain stickiness.
A new study published in the Journal of Chemical Physics puts an end to all the confusion (DOI: 10.1063/1.2906132). The team consists of researchers from the University of Regensburg, Murdoch University, and the University of Strathclyde. Leader of the team, Professor Klaas Wynne explains that ‘the German, Australian, and British teams use complimentary techniques making it possible for the first time to understand the motions of water molecules in solution on time scales of about one-trillionth of a second’ (that is: 1/1,000,000,000,000 seconds).
The team studied solutions of metal salts rather than those of sugars because the salt ions are simpler appearing like smooth spheres rather than knobbly molecules. He continues ‘The metal ions we have studied hold on tightly to a few neighbouring water molecules forming tacky spheres that randomly jam together at high enough concentration like cars in a traffic jam.’ His colleague Dr David Turton explains: ‘You can think of a crystal as oranges in a box at the supermarket, neatly arranged in rows and layers. If you instead throw the oranges into the box, they jam into a random jumble – what physicists call – a glass. We find that ions and sugar molecules in water jam like oranges while the water is free to spin in the pockets between the “oranges”.’
This type of jamming has now been seen in the most unlikely collection of situations such as the movement of dunes in the desert, the flow of grains in silos, and – yes – traffic jams. So, next time you are stuck in traffic, think about how you are simply following the laws of physics like sugar in the cup of coffee you had for breakfast that morning.
The reference to the paper is:
David A. Turton, Johannes Hunger, Glenn Hefter, Richard Buchner, Klaas Wynne, "Glasslike Behavior in Aqueous Electrolyte Solutions", Journal of Chemical Physics, Communication 128, 161102 (2008)
Also of interest is the sister paper:
David A. Turton and Klaas Wynne, "Structural relaxation in the hydrogen-bonding liquids N-methylacetamide and water studied by optical Kerr-effect spectroscopy", Journal of Chemical Physics 128, 154516 (2008)
Click on the thumbnails below for a bigger version and caption.
We gratefully acknowledge funding for this project from the Engineering and Physical Sciences Research Council (EPSRC).
David A. Turton and Klaas Wynne are in the Biomolecular and Chemical Physics group, in the Department of Physics, SUPA, University of Strathclyde, Glasgow G4 0NG, UK
Johannes Hunger and Richard Buchner are in the Dielectric Relaxation Spectroscopy group, Institut für Physikalische und Theoretische Chemie, Universität Regensburg, D-93040 Regensburg, Germany
Glenn Hefter is in the Chemistry Department, Murdoch University, Murdoch, WA 6150, Australia
- 17 February 2017: Our paper "Frustration of crystallisation by a liquid–crystal phase" came out in Scientific Reports today. Read more about this research: Frustrating liquid crystals and watch a movie about it on YouTube here.
- November 2016: We are looking for somebody to join us as a PhD student to work on imaging and laser manipulation of nucleation phenomena. A great project on the border between physics,chemistry, and engineering.
- 1 October 2016: Andrew Farrell joined the group as a new PhD student to work on ultrafast spectroscopy.
- 5 July 2016: Spain's Consul General visits the group on invitation by Mario.
- 6 June 2016: A number of places have taken up our press release. Exclusive: Professor Klaas Wynne On Decoding DNA Sound Bubbles & Human Life on HealthAim.com is probably the weirdest. Also Vibraciones y burbujas de sonido del ADN son esenciales para la vida shown on the homepage of SINC.
- 1 June 2016: Our paper Observation of coherent delocalised phonon-like modes in DNA under physiological conditions was published to day in Nature Communications. See also Sound-like bubbles whizzing around in DNA are essential to life and a similar Glasgow University press release.
- 11 March 2016: Tommy Harwood successfully defended his thesis today at the Strathclyde Institute of Pharmacy & Biomedical Sciences (SIPBS). Tommy studied for his PhD under Elizabeth Ellis (SIPBS) and came to work in the UCP labs in 2012 to do terahertz spectroscopy of biomolecules and optical Kerr-effect spectroscopy of small biomolecules, proteins, and DNA. Although he is not officially our PhD student, in practice he did all the spectroscopy experiments under our supervision at Glasgow University.
Check out our paper "Terahertz underdamped vibrational motion governs protein-ligand binding in solution" came out in Nature Communications.
- November 2015: A £0.5M EPSRC grant “Mapping and controlling nucleation” was awarded to Klaas Wynne and David France in the School of Chemistry. The nucleation of new phases from solution, such as the nucleation of crystals, is of immense importance to both industry and fundamental science. Industrial crystallisation has changed little in the past 350 years and suffers from an embarrassing lack of control with sometimes unexpected and severe financial consequences. The new research programme will image and control the early stages of nucleation. Driving liquid systems very far from equilibrium will allow the creation of meta- and unstable states that will give rise to nucleation and spinodal decomposition. The subsequent highly non-equilibrium processes will be controlled using a novel instrument that will change the study of crystal nucleation and will make the first steps towards control over the polymorph that crystallises. It involves laser-induced nucleation using powerful picosecond and femtosecond lasers, and programmable optics.
- June 2015: We were joined by Finlay Walton, initially as summer project student for summer 2015 and in October as a PhD student. The summer project involves the study of mosquitos while the PhD project will be on microscopy of phase transitions.
- April 2015: UCP group members Chris Syme, Joanna Mosses, and Klaas Wynne win 2nd and 3rd price in College photo competition. See Technical photography competition 2015.
- March 2015: Mapping and Controlling (Crystal) Nucleation. Applications are invited for a fully-funded 3.5-year PhD studentship at the University of Glasgow to study the chemical physics of (crystal) nucleation in the Ultrafast Chemical Physics (UCP) group in the School of Chemistry under the supervision of Prof Klaas Wynne. The PhD project involves (laser) microscopy and laser control of the early stages of nucleation in liquids. It involves laser-induced nucleation using powerful lasers and programmable diffractive optics. The new instrument will be used to carry out experiments that range from creating crystals of the desired type to shedding light on the origins of life. We are now looking for a PhD student who is interested in developing new imaging techniques including the use of spatial light modulators and interfacing a microscope with a high power pulsed laser. The ideal candidate for this position is a chemical physicist, physical chemist, or somebody with knowledge of optics or microscopy. The PhD student will be working alongside a team of postdoctoral researchers with experience in ultrafast techniques, chemical physics, and microscopy. More information and application details can be found here.
- January 2015: Another exciting imaging paper
out for 2015. J. Phys. Chem. Lett. has published our paper Order Parameter of the Liquid–Liquid Transition in a Molecular Liquid in which we use for the first time fluorescene lifetime imaging (FLIM) to study a liquid-liquid phase transition in supercooled triphenyl phosphite.
- November 2014: Our paper "Crystal templating through liquid–liquid phase separation" has been published as an Advanced Article in ChemComm.See also The role of liquid-liquid demixing in crystallisation: icy fluff balls.
- June 2014: Our paper "Terahertz underdamped vibrational motion governs protein-ligand binding in solution" came out in Nature Communications. The University published a news item Proteins ‘ring like bells’, which was taken up by Science Daily and a bunch of other news outlets. Strangely, it was also picked up by a creationist website who thought it was proof of design. The best write up was on an Austrina site Späte Bestätigung für Erwin Schrödinger? For the paper itself see here.
- May 2014: Our paper "Stokes-Einstein-Debye Failure in Molecular Orientational Diffusion: Exception or Rule?" finally came out in J .Phys. Chem. B, see http://pubs.acs.org/doi/abs/10.1021/jp5012457. It truely has the loveliest Kerr-effect/Raman data I have ever seen.
- 21 February 2014: Dr Gopakumar (Gopa) Ramakrishna officially started at Research Assistant in the group. Gopa will concentrate on terahertz spectroscopy.
- 2 December: Today, Dr Mario González Jiménez officially started as a Research Assistant in the group. He'll be working on femtosecond spectroscopy of biomolecules.
- 1 October 2013: Today, Judith Reichenbach officially started her PhD studies in the group. She'll be working on nucleation using femtosecond spectroscopy.
- 18-20 September 2013: Faraday Discussion 167 on Mesostructure and Dynamics in Liquids and Solutions was a sucess with a lot of (heated) discussion. The published volume should come out later in the year.
- April 2013: Another EPSRC grant funded on "Solvation dynamics and structure around proteins and peptides: collective network motions or weak interactions"
- October 2012: Dr Christopher Syme has started as a research associate in the group. He will be using confocal fluorescence microscopy and fluorescence lifetime imaging to study phase transitions in liquids.
- May 2012: Fully funded PhD studentships in the Wynne group. Applications are invited for a number of PhD studentships in the Wynne group. Some of these studentships are part of the Doctoral Training Centre (DTC) in Continuous Manufacturing and Crystallisation (CMAC).
- 9 May 2012: Our paper "The dynamic crossover in water does not require bulk water" just came out in PCCP, see doi:10.1039/c2cp40703e. In a nutshell, it shows that you only need one water molecule to have bulk water properties (as long as that water molecule can form a water pentamer).
18/4/12: The latest issue of PCCP (Physical Chemistry and Chemical Physics), the top physical chemistry journal of the Royal Society of Chemistry, is dedicated to such ultrafast chemical dynamics. The special issue was guest edited by Prof Klaas Wynne in the School of Chemistry at Glasgow University and his colleague Dr Neil Hunt at the University of Strathclyde. Special issue PCCP on Ultrafast Chemical Dynamics.
12/4/12: Glasgow University press release Funding boost for Ultrafast Chemical Physics.
- March 2012: Postdoc position in the group.See http://www.jobs.ac.uk/job/AEF581/research-associate/. Apply online at www.glasgow.ac.uk/jobs(enter Reference Number 001765). Closing date: 29 April 2012
- February 2012: The 2011 UCP meeting in Glasgow was discussed in the March 2012 issue of Nature Chemistry: Ultrafast chemical physics: In search of molecular movies. The future is ultrafast!
- December 2011: The International Workshop on Ultrafast Chemical Physics & Physical Chemistry (UCP 2011) was held in Glasgow. Photos from the UCP2011 event here.
- October 2011: The Ultrafast Chemical Physics group has won a £0.7M EPSRC grant to study liquid-liquid phase transitions using microscopy in collaboration with Chemical Engineering at Strathclyde. EPSRC grant for UCP group.
- July 2011: We would like to cordially invite you to submit a paper to a special issue of PCCP on femtosecond spectroscopy entitled "Ultrafast Chemical Dynamics". Topics that will be covered include: * ultrafast dynamics of reactions in proteins * ultrafast structure and dynamics of liquids and solutions * ultrafast chemical processes at interfaces * ultrafast dynamics of electronically excited states * ultrafast atomic structure and dynamics in the solid state. The special issue will feature a number of invited overviews followed by contributed papers. The deadline for submissions is 14 November 2011. For more information, see http://blogs.rsc.org/cp/2011/06/29/pccp-themed-issue-ultrafast-chemical-dynamics/.
- July 2011: the European Conference of Crystal Growth ECCG4 will be held 17 to 20 June 2012 in Glasgow.
- 7 July 2011: the EPSRC-funded Coherent regenerative amplifier (producing 23-fs 2.7-mJ 800-nm pulses at a repetition rate of 1 kHz) has been reinstalled in our lab again. This is in addition to a new Coherent Micra-10 (producing 15-fs 800-nm pulses at 80 MHz).
- May 2011: A Faraday Discussion on 'Mesostructure and dynamics in liquids and solution' will be held in September 2013 most likely in Bristol.The organising committee consists at the moment of Alan Soper (Rutherford Appleton Laboratory), Austen Angell (Arizona State University), Ken Seddon (Queen's Belfast), Stephen Meech (UEA), an Klaas Wynne (Glasgow University).
- May 2011:
The new ultrafast chemical physics laser lab is pretty much ready. Now all we need is some (working) femtosecond lasers...
- 16 November 2010: New website for the International Workshop on Ultrafast Chemical Physics & Physical Chemistry UCP 201.
- October 2010: Next Ultrafast Chemical Physics meeting (UCP 2011) set for 14-16 December 2011 at the University of Strathclyde. Confirmed speakers include Prof David Klug (Imperial College, multidimensional spectroscopy), Prof Andrea Cavalleri (University of Oxford, femtosecond X-ray science) and Prof Klaas Wynne (University of Glasgow, terahertz spectroscopy). In addition we have confirmed attendance of Prof Dwayne Miller (University of Toronto) as plenary speaker for the conference.
2 October 2010: Positions. A lectureship (assistant professorship) in ultrafast physical chemistry is available. The ideal candidate would be interested in ultrafast femtosecond spectroscopy of the condensed phase or an allied area. Brand new lab space will be available. Ref: 00057-10, Closing Date: 29th October 2010.
- 1 November 2010: KW's official start as chair in physical chemistry in the School of Chemistry at the University of Glasgow.
- August 2010: Our paper in JACS (described in Serving nanoparticle “soup”) has been cited 19 times on Web of Science exactly one year after its publication. It describes how using multiple spectroscopies, we discovered mesoscopic structure in room-temperature ionic liquids.
- 24 March 2010: Our paper The effects of anion and cation substitution on the ultrafast solvent dynamics of ionic liquids: A time-resolved optical Kerr-effect spectroscopic study, JCP 119, 464 (2003) was selected as highlighted reference in the JCP Spotlight Collection on ionic liquids, March 2010.
- 12 March 2010: Our paper Universal nonexponential relaxation: Complex dynamics in simple liquids was selected JChemPhys editors’ choice as one of the most innovative and influential articles in the field of Chemical Physics in 2009. See http://jcp.aip.org/jcp/editors_choices_2009.
- 5 January 2010: Our paper Universal nonexponential relaxation: Complex dynamics in simple liquids was the 3rd most downloaded paper of J. Chem. Phys. in December 2009.
- 5 August 2009: Read more about our latest paper in JACS in Serving nanoparticle "soup".
- 4 August 2009: We were joined by new postdoc Marco Candelaresi.
- May 2009: New ultrafast physical-chemistry lab is ready!
- 30/31 October 2008: The 2008 ultrafast physical-chemistry (UCP) meeting was held at Strathclyde.
- 10 July 2008: We were joined by new postdoc Kitsakorn Locharoenrat.
- 23 May 2008: Our paper "Glasslike Behavior in Aqueous Electrolyte Solutions" was selected "Editors' Choice" in the 23 May issue of the journal Science (PDF, 800kB).
- 12 May 2008: Groups wins £0.6M EPSRC grant "Two-dimensional terahertz–IR spectroscopy: a unique probe of ultrafast hydrogen-bond dynamics of liquid water and model systems" by KW, JOK, and DJSB.
- 2 May 2008: Strathclyde will host the "International Workshop on ultrafast physical-chemistry 2008 (UCP ‘08)" on 30/31 October 2008 to be held in the Senate/Court suite. Plenary speaker is Prof Robin Hochstrasser FRSE (University of Pennsylvania). Confirmed invited speakers are Prof Casey Hynes (CNRS, Paris and University of Colorado, Boulder), Prof Charles Schmuttenmaer (Yale), Prof Majed Chergui (Ecole polytechnique fédérale de Lausanne), Prof Mischa Bonn (AMOLF, Amsterdam), Prof Peter Hamm (University of Zurich), and Prof Thomas Elsaesser (Max Born Institute, Berlin). The workshop is organised by Angus J. Bain (UCL), David Klug (Imperial), Steve Meech (UEA), Neil Hunt (Strathclyde), and Klaas Wynne (Strathclyde).
- 24 April 2008: Our paper "Glasslike Behavior in Aqueous Electrolyte Solutions" came out in J. Chem. Phys. A summary of the paper in simple terms (best attempt anyway) is on the page The science of syrup and traffic jams.
- 4 March 2008: Visiting professor Robin Hochstrasser of the University of Pennsylvania has been elected Honorary Fellow of the Royal Society of Edinburgh. This is a prestigious fellowship for scientists of great international renown and we are delighted that Robin has been honoured in this way.
- 18 March 2007: New paper in JACS on terahertz spectra associated with a helix to coil transition in a peptide. Read more about it in the research highlight Observing ‘The Lubricant of Life’
- 10 January 2007: New paper on terahertz emission from nanostructured surfaces has come out in PRL. Read more about it in the research page on terahertz technology.