Dec 13

Keeping the Best Company – Part 2

Marta’s journey has now taken her to Geneva, where she has been hosted by István Szilágyi in the Laboratory of Colloid and Surface Chemistry (LCSC).  Marta had a productive time catching up with all the group members, including group leader Michal Borkovec, and a former visiting student at the SISM Group, Valentina Valmacco.

Marta delivered a seminar on wetting properties of ionic liquids – work from our PhD student, Iliana Delcheva.

Before leaving, Marta received a wonderful gift from Santa to bring home to the SISM Group – some chocolates (see below 🙂 ).  Santa relied on his helper, Valentina, to deliver the treats.

Valechocolate from santa

Dec 10

Keeping the Best Company

Our group co-leader, Marta, is on an odyssey of science.  Her current location is the Laboratory for Surface Science and Technology (LSST), a part of the Department of Materials at the ETH Zürich, Switzerland.  She is being hosted by Antonella Rossi at the LSST Group.

Marta is doing some X-ray photoelectron spectroscopy with Antonella and her PhD student, Andrea Arcifa.  Marta, Antonella, and Andrea are performing experiments on ultrathin ionic liquid films on solid surfaces, with a study designed to continue work from a recent paper of the SISM Group.

Marta is also currently the UniSA node manager of a multi-group research grant awarded by the Swiss National Science Foundation, for which our mentor, Emeritus Laureate Professor John Ralston, is one of the named investigators.  The collaboration involves Prof Nic Spencer (Group Leader of the LSST), Prof Michal Borkevec (LCSC, University of Geneva), and Prof Paul Dyson (LCOM, EPFL).  Marta is visiting these collaborators to report on the SISM Group’s latest work on wetting of surfaces with ionic liquids.

Andrea and Antonella resample

Dec 01

First Day of Summer, First Day of Science

December is an exciting time in the SISM Group, as we usually welcome a new vacation student to the team.  This year is no exception, and we have the good fortune to welcome two new vacation students today: Jennifer Wu, and Stephanie MacWilliams.  Jennifer is a repeat offender :), as she also worked in our labs last summer (and did Honours with us).  Stephanie is experiencing research for the first time.

Vacation scholarships are a great way for undergraduate students to engage in active research projects, rather than the more sterile (but essential for scientific training) teaching laboratory/practicals that form the bulk of lab-based undergraduate education.  Both Stephanie and Jennifer have projects that will generate new data and new insights into the soft matter systems that are the focus of their research.

Jennifer is continuing her past vacation/Honours research into bubble collisions with solid surfaces, which is of relevance for mineral flotation. Her work will now shift beyond the use of biopolymers to prevent the attachment of bubbles to hydrophobic surfaces, to the study of surfactants, and how they further complicate this bubble-surface attachment process.  The need to increase the complexity of the system comes from the inherent complexity of flotation: multiple different chemicals and multiple different mineral surfaces.  This new phase of the project is in collaboration with one of our major industry partners.

Stephanie will be the lab buddy for our PhD student, Tracey Ho.  Tracey does research into polymer surface treatments for biolubrication.  Stephanie’s involvement in the project will bring with it a change in focus for the work – looking at protein adsorption to the polymer surface treatments, to try to gain insight into how the polymer layers will interact with a biological environment.

jennifer and stephanie

Nov 28

Hot off the Press: Bubbles and Graphite

Jennifer Wu, our Honours student, has just had her first paper accepted in Soft Matter.  This is the same work for which she recently won a poster prize at an engineering showcase/outreach event at Adelaide Uni.

The paper focuses on the study of bubble collisions on hydrophobic surfaces, in this case graphite, and the effect of molecularly thin layers of polymer on the attachment of bubbles and the dewetting (water displacement) at the interface.  Dewetting (and wetting) of solid interfaces is an important aspect of a number of industrial processes, including coatings and mineral flotation.  It is the latter of these two processes that was the motivation for this work.

Depending on the mineral processing goal, graphite/graphitic material either needs to be recovered or rejected in flotation. When pure graphite is the target valuable material (which can then be further processed to make graphene), one needs to understand the factors that would prevent recovery, such as the presence of biopolymers or surfactants.

Conversely, sometimes minerals of little value are coated with carbon material, which results in collection of unwanted waste.  In this situation, it is important to discourage recovery of graphite-like material, which can be achieved with biopolymers.  It was for this reason that carboxymethylcellulose was studied for its interaction with graphite, the subsequent effect on bubble attachment onto graphite, and flotation of graphite particles.

Jennifer’s work, although using an applied system, was quite fundamental in nature.  Jennifer was able to correlate coverage of the polymer (determined using the atomic force microscope) with an enhanced effect on graphite recovery, and on the slowing down of the dewetting process.  In addition, she was able to make connections between the polymer layer characteristics and the molecular motion of water at the interface during the dewetting process.  This level of fundamental understanding is required if advances are to be made in developing polymers to influence flotation outcomes.

graphite paper

Nov 19

Summer Holiday…….in the lab

When most PhD students envisage a 4 week break in a different city, most would probably not think of having to do even more lab work :), but that is what is in store for Emma Brisson, who is visiting the SISM Group from her normal home at the University of Melbourne.  Emma’s research project is centered on synthesizing novel polymers for application in mineral processing.  She has come to the SISM Group to do some spectroscopy experiments that are designed to tell her how (and how quickly) her polymers stick to mineral surfaces.  This additional research has grown out of a collaboration between David and Marta and Emma’s supervisor, Prof George Franks (which gave rise to a recent publication from the group – see here).

Adelaide chose to welcome Emma with a 36 degree Celsius day – quite common for Adelaide at this time of year, and hopefully not too much of a shock for this Melbournite.

Welcome Emma 🙂

Emma B cropresize

Nov 01

Hot off the Press: Stimulus Responsive Polymer Adsorption on Talc

The SISM Group has added another paper to the 2014 list.  This time, the focus is on polymer adsorption on talc – studied using vibrational spectroscopy.  The paper has just been published in Physical Chemistry Chemical Physics.  The technique of attenuated total reflection (ATR) infrared spectroscopy allows us to follow the adsorption of polymers onto real mineral surfaces, as it occurs from solution.  It also allows us to control the solution conditions of adsorption, including elevating the temperature.

The paper published focuses on poly (N-isopropyl acrylamide), more commonly known as PNIPAM.  This polymer is the archetypal stimulus responsive polymer – a polymer whose properties change dramatically when exposed to a particular trigger.  PNIPAM is temperature responsive, and undergoes a change in conformation (and solubility) when its temperature in solution rises above 34 degrees Celsius.

The spectroscopic study we have published looks at the effect of adsorption to a hydrophobic surface (talc) on the conformation of the polymer at room temperature.  The ATR spectra indicate that the polymer adopts a conformation on the surface of the talc similar to that of the polymer in solution above the trigger temperature.  This observation allowed us to infer the likely method of binding of the polymer on the talc surface.

talc pnipam toc resize

Oct 30

Poster Prize for Jennifer

The SISM Group Honours student, Jennifer (Jueying) Wu, presented the poster of her Honours research project at the Ingenuity event held by the Engineering Faculty of Adelaide University.  The School of Chemical Engineering (where Jennifer is studying for her BEng) organised a series of poster prizes for the students of the school, and Jennifer was the recipient of the ‘Best Poster with New Technology or Process Theme’ award (sponsored by Manta Controls).

The poster was entitled “Bubble-Surface Interactions with Graphite”, and it detailed her experiments on the effect of adsorbed polymers on bubble collisions with graphite surfaces.  She studied the collisions with high speed video microscopy, and characterised her graphite surface (with and without polymer) using atomic force microscopy and zeta potential determination.

All of Jennifer’s supervisors (Marta, David, Iliana from SISM, and A/Prof Yung Ngothai from Adelaide University) and SISM group members are very proud of her achievement today.  Well done Jennifer 🙂

Jennifer poster crop resize

Sep 18

Hot off the Press: How Salt Affects Bubble Interactions with Polymer-Treated Molybdenite

Mohammad Kor (one of the SISM Group students) has just had the first of his core papers from his PhD work accepted in Langmuir. The paper focuses on the adsorption of a common polysaccharide polymer (carboxymethyl cellulose) on molybdenite – a very valuable metal sulfide mineral.  Moly (as we like to shorten the name) is recovered from ore deposits using the flotation process.  Understanding how polymers and surfactants adsorb to the surface, and how that then affects the mineral wetting properties, is crucial to ensuring that no moly is lost when ore is processed.

The paper details a number of experiments that allowed us to interrogate the effect of the water content (types of salt and concentration of salt) on how the polymer adsorbed onto the surface.  The consequence of the altered adsorption was reflected in how bubbles attached to the surface, and this was shown to alter the recovery of moly in flotation.

Kor Lang ToC

Sep 13

Hot off the Press: New Drug Release Mechanism for Polymer Films

A new paper has just been published in PCCP by the SISM Group – on storage and release of a therapeutic molecule from a polymer surface treatment.  Surface-mediated drug delivery is a strategy used for biomaterials, to ensure proper interactions with the surrounding biological matrix.  Knowing how much of the active molecule can be stored within the film, and the manner in which it is released when the biomaterial is exposed to biological fluids, is essential for the design and adoption of novel surface treatments.  The work that has just been published focuses on a therapeutic molecule from natural sources: curcumin, which is an extract of turmeric. The work was carried out by a number of students from the group: Yongjin Shin, Weng Hou Cheung, and Tracey Ho.  They were able to determine, through the use of a range of techniques, that the curcumin is released only when the polymer film is dried and then exposed to solution, rather than from prolonged immersion in a release solution.

curcumin ToC

Aug 19

The Research-Teaching Nexus

The SISM Group is currently hosting two 3rd Year students from the UniSA BSc Advanced Materials Program. Jessie Webber and Brock Le Cerf are carrying out research for their Applied Science Project.  They will spend the next three months doing experiments, as part of a drive to embed research within undergraduate science courses.

Jessie will spend her time looking at the interaction between biopolymers and calcium carbonate, a material that is grown and sculpted by marine animals to create shelter and structures integral to their protection and survival.

Brock will be studying the interaction of enzymes with nanomaterials used in controlled drug delivery within the human body.

Welcome to the group 🙂

Brock and Jessie3

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