Tuesday August 13, 2007

LAST DAY AT CONTE! I do not want to leave. I have learned so much and have gained a deep appreciation for the excitement and commitment involved in true research. We all have had different experiences, but have come away with a variety of skills and an amazement at what is being investigated right in our own back yard. From chemotherapy delivery systems to antibacterial cloth, from fuel cells to solar cells, from biological energy generation systems to wrinkling and fundamental principles of physics, it is all less than an hour away from home. So many people here are incredibly smart, and everyone is always willing to help you and teach you and share what they know.

Greg Dabkowski took us to lunch with our mentors, then we attended our last Russell group meeting. Professor Russell is mighty impressive; I have no idea how he can juggle all that he does and be on top of everything going on the lab and all of the new advancements being made in his field. Efren and I said a few words of thanks to the group, and said farewell.

I had a meeting with Dr. Crosby and Greg Dabkowski at 2:30 to see how Minnechaug can forge a relationship with MRSEC. I will meet with Mr. O'Shea this week and see if this is feasible. I will miss my time in Amherst, but never will I forget this experience.

Monday August 12, 2007

There is so much to do in two days. Efren and I are working on our PowerPoint presentation of our research experience. I will present it next June to the new crop of R.E.T.s, and Efren will join us by Skype video. Jiangshui is popping in and out getting our data and copying our PowerPoint to show to Professor Russell. After lunch, Dian takes us to see the set up and operation of the Transmission Electron Microscope (T.E.M.).


The T.E.M. has a sizable quantity of liquid nitrogen added to it prior to its use. Above right, Dian fills the canister to transport the liquid nitrogen, and below, she empties it into the T.E.M. while standing on a chair!


Next, she loads the sample, which is on a tiny copper grid, onto the sample holder.


She places the sample holder into the T.E.M. and begins evacuating the chamber housing the sample.



Unfortunately, I could not get a picture of the screen, but here are some T.E.M. images from a different session.



Afterwards, Efren and I attended the doctoral defense of Ryan Murphy, then returned to the fifth floor to work on the PowerPoint and our blogs.

Friday August 10, 2007

Today is Dave's last day. We are finishing our data analysis and preparing a presentation for Tuesday and for next June when I address the incoming R.E.T.s. Jiangshui asked us to consolidate our data with the appropriate pictures into folders describing surfactant concentration, date of experiment, and photographs analyzed.


This took much of the morning. Greg Dabkowski came by with our checks, and I asked him if it would be appropriate for me to approach Dr. Crosby about having some of my students perform research over the school year in conjunction with his research here. During lunch, Greg told Dr. Crosby of my hope for the students to do actual, relevant research, and Dr. Crosby spoke to me at length about the prospect. He was excited by the idea and will meet with me, Greg Dabkowski, and graduate student Chelsea early next week to see what we can do together. This is thrilling!

Thursday August 9, 2007

We are determined to complete the wrinkling experiments today, or at least I am. We crunch some more data in the early morning, then make and take films to Hasbrouck to complete the 0.12% surfactant experiments. We float the films prior to adding the surfactant, and I manage to release a TON of tiny bubbles into the dish which decide to congregate under Dave's floated membrane. My bad. My membrane and solution are fine, however, and we are able to get some good data. We took Jaingshui to lunch at Rafters, and that was a great time. We presented him with a gift certificate to his favorite restaurant as a token of our gratitude for his time and patience. We try to also treat him to lunch, but he has a fit, so we let him cover the tip.

After lunch, I make three more films, and Efren and Dave each make two. We return to Hasbrouck and Dave and I get data for 0.12%. I then float two films in a dish containing 160 ml of water and proceed to add 40 ml of 5% surfactant (8 transfers with a 5 ml syringe). The membranes go CRAZY on the surface, flying around the dish; I am adding the surfactant slowly but you would think I was adding it with a fire hose at full blast. One of the two membranes collides with the needle, destroying that film. The data I get from the 1% is the best ever, and the film is clean. Efren is also able to get data for a 1% solution, even though a few teeny bubbles appear under his membrane.


We return to Conte and crunch our data. The graphs look pretty good! We will complete our data reduction tomorrow.

Wednesday August 8, 2007

Jiangshui has made the big time! His research, which we are busy confirming, was published in the August 3rd edition of SCIENCE. We are excited for him, and feel that we have helped him in his work by expanding his research by floating films on water with surfactant mixed in. He still has many aspects of this research to explore.

This morning has been set aside for presentations by the R.E.U.s at the conclusion of their program. These 11 students from all over the country, also funded by the National Science Foundation, have conducted significant research with the faculty of the Conte Polymer Research Center.


Ashlan, above left, investigated synthesis of antimicrobial polymers using the organism's innate biomembrane destruction mechanism (alpha defensin in humans) linked to norbernene, a synthetic polymer, to create an amphiphilic molecule with a half life four to five times that of the alpha defensin alone. Dan, above left, investigated the use of DNA and its splicing to create self-assembling nanostructures (proteins).

Samantha, above left, from Mt. Holyoke College, investigated the synthesis of therapeutic protein-polymer conjugates. Anna, above right, from Virginia Tech, is working in the Russell group making organic solar cells using P3HT and TiO2.



Laurel from Bucknell, above left, discussed her work with polyelectrolytes (charged polymers), while Mike used the Venus Fly Trap and Lotus leaf for inspiration for his work with responsive polymer surfaces.



Steve from Southern Illinois University at Carbondale has worked on nanoimprint lithography and its role in microfabrication, making organic field transistors using soft imprint lithography.

This synopsis represents only half of the presentations; connect to the photo album to see the other R.E.U. presenters and a description of their work.

After lunch, we decided to analyze data that had piled up on us. We spent five hours (each of us!) crunching and counting, then consolidated all of the data onto a single data table and constructed individual graphs for no surfactant, 0.03% surfactant, 0.08% surfactant, and 0.12% surfactant. We still need to gather more data for 0.12% surfactant, and 1% surfactant. We call it a day at around 5:30 pm.

Tuesday, August 7, 2007

One week left for Efren and me, three more days for Dave. We arrived at 9 AM and prepared one film each (except for me, I made 2 films because I like having insurance), then took them to Hasbrouck. Dave and Efren floated their films in pure water (so much easier!) and I added the surfactant to the containers; neither of them like using the needle and syringe. We waited for 45 minutes, during which time we went to the UMass Employment office to see about getting our mandatory retirement withholding returned to us. The clerk in the office said that we should not even begin the process of obtaining a refund until mid September. It seems that the wheels of bureaucracy turn mighty slowly; this may be my Christmas spending money. We return to the Hasbrouck lab, and Efren is able to wrinkle his film, but a very odd event occurred. After he put his first 0.2ul onto the film, Efren took a few minutes to refocus the camera and when he returned to shoot the closeup of the wrinkles, the drop was GONE! It is so humid in the room in Hasbrouck that it is hard to imagine that the water evaporated, but it surely seemed to. Jiangshui says that there may have been a tiny pinhole in the membrane, and that he has had this happen to him before. Dave begins his process, and I decide to use one of my films to try to float it on the surfactant solution left over from Efren's wrinkling experiment. It worked! I was able to cut and float my film on the prepared 0.12% surfactant solution, then perform the wrinkling experiment. I am most pleased with myself!

Although Professor Russell is in California, he is treating the entire research group to lunch at the House of Teriyaki Restaurant in North Amherst. So nice of him! He calls from California to say goodbye to Anna (R.E.U.) and to the three of us while we are having lunch. I am really enjoying all of the diversity in the group...at my lunch table alone today is Martha from Colombia, Jiangshui from China, Suresh and Siva from India and Ali from Turkey, as well as Efren (Texas) and Dave (upstate New York).

This is a tremendous gift that I did not anticipate when I was selected to participate in the experience.


After lunch, we prepare more films and try to float them on this morning's solutions. No success at all, so we retrieve our data from the morning and return to Conte to analyze it. Big doings at Conte though..Suresh's new instrument (for photovoltaic nanodevices) and three glove boxes (to maintain a dust free, humidity free environment with no oxidizers in which spin coating, metal coating, and conductivity measurements of photovoltaic nanodevices can be conducted) has arrived!

It is a BIG DEAL! Everyone helps him roll the instrumentation into a storage area until the maintenance crew can run the plumbing and electricity for its permanent home. I hope it can be in place before we leave, but I doubt it.

Efren and Dave work on data analysis for the rest of the day, while I catch up on this blog.

Monday August 6, 2007

We arrived early and made the 0.08% surfactant solution in Hasbrouck, then returned to Conte to prepare more films. I did not prepare films as I had acquired two sets of data on Friday for this concentration of surfactant. Dave and Efren met with success this morning and were able to acquire some data. After lunch, we downloaded the data onto our flashdrives then returned to Conte to use Image J and Excel (which Efren formatted with the appropriate formulas) to begin data analysis. We decided that we will float the films on pure water, then add the surfactant to prepare the 0.12% surfactant solution tomorrow, since we are already having trouble floating the fims with this lesser surfactant concentration.

Friday August 3, 2007

Lots of work today. By 9AM we had set up the 0.08% surfactant solution in the Hasbrouck lab and returned to Conte. Each of us again spin coated 3 films of 1.4% polystyrene in toluene, then returned to Hasbrouck to float and wrinkle. The more surfactant present, the greater the difficulty floating the films, but the easier it is to manipulate the films into position under the microscope. I had success with two films, Dave was able to complete the wrinkling protocol for one film, and Efren's films just would not let go of the glass slide. We decided that it was necessary to increase the angle of the slide as it entered the water, and I found that I had to use the probe to move the liberated film away from the glass surface so that it would not re-adhere before I could remove the slide from the water.

A noon lunch of pizza was followed by a presentation by Chelsea, who is a first year PhD candidate from N.C. State. She has a BS in Textile Engineering and has worked in industry for several years since her graduation. She is affiliated with the Crosby Group and is working on the interactions that occur at the interfaces of soft matter. She took a few minutes to explain a little more about the PhD program; there are 30 hrs of coursework during the first year, including classes in Polymer Synthesis Chemistry, Materials Engineering, Polymer Physics, Synthetic Chemistry and Polymer Characterization. This is a heavy load for first year students. In addition to the coursework, they are beginning research and working to decide which area of polymers they will focus on for their PhD (this also includes selecting one of the professors to serve as research supervisor).

After Chelsea's presentation, we attended the Crosby group meeting to see Renee, Mary and Lauren present the results of their research. Their experience here has been quite different from ours. They have made several discoveries which Dr. Crosby believes to be worthy of publication. Their research project is entitled "Long Range Alignment of Surface Wrinkling".

During their experiments, they have used PDMS (polydimethylseloxane) films about 1mm thick, which they have then subjected to horizontal stress. After stressing, the PDMS is soaked in ethanol to induce swelling. Cracks form in the PDMS perpendicular to the strain plane, while wrinkles occur after ethanol exposure that are parallel to the strain plane. The wavelength and amplitude of the wrinkles are related to the length of time the PDMS is stressed.

Lauren, who is an art teacher, demonstrated the media she has artistically "stressed" to reproduce wrinkling in her classroom. Her greatest success was achieved with tissue paper, clear acrylic medium, and foamboard. She was able to form and maintain wrinkles of the same wavelength when the tissue paper was applied over the acrylic medium to the foamboard. It was really neat to see the applications for the art classroom.

Thursday August 2, 2007

A much better day in the lab. We met in Hasbrouck Physics Hall this morning at 9 AM to set up the 0.03% surfactant solution at the optical microscope where we take the wrinkling pictures. Jaingshui suggested that we add the surfactant under the water and stir it with the paddle we use to move the film around in the bath, then let it sit for at least 30 minutes. After we set up the solution, we returned to Conte and prepared three films each. The spin coater had been acting up yesterday afternoon, not holding continuous speed, but it is working fine today. Once we each prepare our films, we return to Hasbrouck for the wrinkling experiments. I went first today, and had no trouble floating my first film and running the wrinkling experiment. Dave was able to get one set of data, but Efren's films folded or would not disengage from the glass; this is the problem I had yesterday. We are using a lighter touch cutting the films, and they seem less dirty. At the end of the morning's work, we decide to clean the microscope base, light source, and the dish holding the solution, since we are all noticing dirt in the background. WE spend about a half hour cleaning. We then prepared another 0.03% surfactant solution, and went to lunch.

It is Efren's birthday, so we celebrate with cake after lunch. Good stuff! We made three more films each, and each of us is able to get a set of data for analysis. We return to Conte for an afternoon of data analysis using Image J and Origin.

Wednesday, August 1, 2007

Only one set of data from yesterday's work can be used; the other films were either dirty or did not have smooth edges. Any artifact in the film can affect the wrinkling. This morning, we each make three more films and carry them to Hasbrouck. We prepare another 0.03% surfactant solution. Dave and Efren have success floating and wrinkling films, but none of my films will separate from the slides. The films are cut and do begin to separate, but then they fold back on themselves and will not free themselves from the substrate. Trying to figure out my problem, we realize that my films were on the top of the pile during transport to Hasbrouck and were exposed to the sun and the heat during the transport; Jiangshui thinks this is the problem. I return and try to make more films, but the spin coater is throwing the slides off of the base. Jiangshui thinks the O-Ring is worn in one area, so this afternoon we will try anchoring the slides in a different area on the base.

After lunch, we each prepared two more films. Jiangshui's hypothesis about the worn spot on the O-ring appears to be valid; we are orienting the slides differently and they are staying on the platform. In addition, we covered the films during transport so that the sun would not affect them. We added 1.2ml of 5% surfactant to 200 ml of water and waited 20 minutes for equilibration. Jiangshui felt that we may be scoring the film too hard and are kicking up glass fragments onto the film, that is why they are all looking so dirty. He suggested that we use a lighter touch while cutting, so we try that this afternoon. Not one of us is able to successful float a film. We are continuously told that there are far more bad days with research than good days, and today seems to be one of those bad days. No meaningful data was generated.

Tuesday July 31, 2007

We begin an actual experiment, determining the effect of surfactant concentration on wrinkling. We made three slides each, then floated them on a 0.03% solution of surfactant, adding 0.2ul drops of water to incur wrinkling. The wrinkles are longer with surfactant in the water; we can see this without analyzing the data with Image J. We have problems with the films however, many are dirty. At the end of the day, Jiangshui added about 5 ml of surfactant to the water and you could see the wrinkles change as the surfactant dissolved into solution - they not only increase in length, they seem to increase in amplitude. Jiangshui is trying to discover a way to measure the change in amplitude in hopes of uncovering an explanation for it.

Monday July 30, 2007

This video was referenced last Tuesday when Jiangshui gave his paper presentation. It represents a drop of colored water on a thin triangular polymer film causing a phenomenon called "Capillary Origami." It was taken from "Capillary Origami:Spontaneous Wrapping of a Droplet With an Elastic Sheet" by Charlotte Py, Paul Reverdy, Lionel Doppler, Jose Bico, Benoit Roman, and Charles N. Baroud from Phy.Rev.Lett.98.156103 (issue 13 April 2007).I think it is really cool!


This morning, it is necessary to recalibrate the Tensiometer to water first, as it was used in another application over the weekend. We prepared a new 0.09% surfactant solution, then did three runs to determine its surface tension. The three readings were averaged, and the surface tension of the 0.09% solution is 46.5. Jiangshui now wants us to float films on water with surfactant added. We calculated how much of the 5% surfactant stock solution we needed to add to 200 ml of water to achieve the desired surfactant concentration. We will be counting the wrinkles on films floating on 0.03%, 0.08%, 0.12% and 3% surfactant solutions. Jiangshui's surface tension readings for the various surfactant concentrations are different from our readings.



Tomorrow we will prepare films, float them on the various surfactant concentrations, and count wrinkles!

Friday July 27, 2007

Efren and I arrived by 9 to set up the 0.12% solution for three tensiometer readings. The first result is 40, the second run gave us 44, and the third run gave us 42.

Jiangshui then suggested that we determine the surface tension of a 3% sample. This seems to be quite a jump in concentration, but he wants us to see that there is a limit to the effect of surfactant concentration on the surface tension of water. We will investigate both .30% and 3%.

At 10 am we attend the dissertation defense of Edwin P. Chan, a member of Dr. Alfred Crosby's group. This is Dr. Chan's fourth year; upon receipt of his degree today, he will do postdoctoral work at M.I.T.. His dissertation, "Adhesion of Patterned Polymer Interfaces", was inspired by nature; specifically the ability of beetles, bugs, and geckos to climb up walls.

He examined research that indicated that as the mass of the organism increases, the number of setae per area increases while the diameter of each seta decreases. In addition, the shape of the setae vary in nature, some are nearly round (bugs) while others are nearly triangular (gecko). Edwin compares adhesion using a single smooth surface to a surface with a patterned series of posts, then he varies the size, number, and shape of the posts to see the effects of these changes on adhesion. After this work was concluded, he determined that the establishment of these patterns was both labor intensive and expensive, so he sought another means to establish a pattern of adhesion posts. He then investigated wrinkling. He was able to establish a relationship between wrinkling pattern, pattern orientation, and the area being subjected to the stress that causes wrinkling. This provides a quick, inexpensive, and simple way to affect adhesion. This was an extremely interesting presentation, and Dr. Chan's knowledge and ability to explain precisely what he had done, what it meant, and the mathematical and scientific principles behind it on multiple levels was so impressive. I did not feel lost at any time, even though all of the math he presented was most assuredly way over my head. He could rapidly go from gecko feet to Young's modulus and back again, explaining why wrinkling would increase adhesion.

We returned to the lab to set up another reading for the 0.12% solution, then went to lunch. The usual Friday fare was followed by a 4th year PhD candidate's explanation of her work. Liz is a graduate of Carnegie-Mellon with a degree in Chemistry.

She is working on nanoparticles for drug delivery systems, concentrating on the use of gold and PEG (polyethylene glycol) nanoparticles, which are amphiphilic and aggregate at an oil/water or nonpolar/polar liquid interface. We then returned to the lab to complete our work with the tensiometer.

Thursday July 26, 2007

Today the tensiometer is really getting a workout. We are determining the surface tension of the solutions we prepared yesterday, each concentration in triplicate. The 0.03% solution results from yesterday are 59, 60, and 61. We are satisified that this surface tension is around 60.

We then empty the 0.03% solution from the syringe, and rinse the syringe three times using the 0.06% solution. We then set up the tensiometer to take three readings on this solution, and the surface tension of the 0.06% solution was determined to be 50, 51.5, and 51, so the average surface tension is 51 for 0.06% surfactant solution. We will continue with the remaining solutions tomorrow.

Wednesday July 25, 2007

As soon as we arrived, we headed for the microscopy lab to receive instruction on the operation of the Atomic Force Microscope (AFM). We will not use this instrument, but Ji Xu explained the principles of its operation and how to use it.


The AFM is not optical; it has a tip (visible only using an optical microscope) that vibrates vertically in response to an oscillating voltage, so that in effect it gently taps the surface of the sample at a constant amplitude as it moves along its surface. The constant amplitude of the tapping allows the tip to move up and down with the variations of the topography of the sample. The tip is attached to a cantilever which is just barely visible to the naked eye; this is attached to a black matrix that is large enough to be manipulated into position on the instrument (below, left). Prior to analyzing the sample, the AFM must be calibrated for that specific sample. First, the tip size is selected; the smaller the tip, the higher the possible magnification. Resolution is determined by the number of oscillations, or vibrations, of the tip on the sample surface, and magnification is again affected by the amplitude of the oscillation of the tip.



A laser beam shines down onto the cantilever and, as the tip moves across the topography of the sample, the beam is reflected at different angles. The reflected laser is collected by receptors that are analyzed and interpreted by the computer to create images. The image on the left of the screens below is the topography of the sample; higher structures appear lighter in color. The images on the right indicate the hardness (how densely the molecules in the sample are packed) of the sample: dark areas are hard and light areas are soft. Ji Xu has hexagons that self-assembled as his polymer annealed. A close up of one of the hexagons is seen below, left, while several are visible in the less magnified image seen below right.



Results are also graphed for interpretation (below, left). The sample can be manipulated under the AFM to a position that correlates to a position previously viewed under a high resolution optical microscope (below, right) so that images obtained from the optical microscope can be compared to the images obtained using the AFM.


After lunch, we prepared surfactant solutions of various concentrations that we will use in next week's wrinkling experiments. From the 0.5% solution prepared on Wednesday, a 1/4 dilution was made, resulting in a 0.1% solution. Twelve ml of the 0.1% solution was mixed with 8 ml of water to prepare a 0.06% solution; 18 ml of the 0.1% solution was diluted with 2 ml of water to create a 0.09% solution. A 0.12% solution was made by mixing 4.8 ml of 0.5% surfactant solution with 15.2 ml of water. We then set up the Tensiometer to measure the surface tension of the 0.03% solution again.

At 2 pm we went with Jaingshui to meet with Dr. Menon of the physics department in Hasbrouck. The first discussion focused on our progress with wrinkling, use of the reflectometer, and data analysis with ImageJ and Origin software. We then discussed problems that we could encounter using the surfactant. The surfactant is amphipathic, and the polar tails actually stick up from the surface of the water, making the environment at the surface of the drop different from the drop's internal environment. The same is true in a bowl of water/surfactant solution: the hydrophobic tails of the surfactant stick up while the hydrophilic heads are oriented toward the water. In the rest of the water, the hydrophobic tails of the surfactant are attracted to one another and form mycellae. The mycellae eventually form spheres (head to head/tail to tail attraction). If the spheres are broken apart (agitation, heat) they may reassemble as cylinders. If the concentration of the surfactant continues to increase, and the cylinders are broken apart, then lamellae may form. The formation of these various structures is dictated by the general rule that material tries to form the geometrical shape with the smallest surface area relative to its concentration.

Jiangshui then discussed the next focus of his research with Menon. Jaingshui will be working to create experimental evidence to support the mathematical explanation for wrinkling patterns.