*colored icons can be clicked, black icons mean that the file is not available yet
Bulk polymerization
A polymerization technique typically using a liquid monomer to synthesize a polymer using free radicals as initiators.
For example – synthesis of polystyrene. The initiator should dissolve the monomer. The monomer units can then be propagated into chains before the termination. This process is very exothermic, and the polymer obtained is pure.
Emulsion polymerization
Also a free-radical initiated polymerization but the monomers are now in an emulsion of water.
For example – synthesis of a type of rubber/latex, polyisobutadiene. The process starts with water, monomers, and a surfactant which prevents coagulation. This process can result in high molecular weight polymers, but the surfactants and other additives are typically difficult to remove.
Gel permeation chromatography (GPC)
Gel permeation chromatography (GPC) is one of the most powerful and versatile analytical techniques available for measuring the molecular weight distribution of complex polymers. The polymer sample is dissolved in the mobile phase (solvent) and flows through the porous column packing in such its constituent parts are separated by molecular size (hydrodynamic size). The higher molecular weight polymer component travels at the faster speed through the stationary phase, while the lower molecular weight one travels at slower speed because of tortuous path in and out of the pores of the packing beads in the column. After exiting the column, the separated component of the polymer is detected by the detector. In this lab, we have EcoSEC high performance GPC system (HLC-8320GPC), which compactly assembles an auto-injector, auto-sampler, high pressure pump with a degasser, and an oven containing the two columns SuperHM-H in series, along with DRI detector. The SuperHM-H column has ID of 6 mm and length of 15 cm fully packed with ultra-efficient 3 μm porous, highly cross-linked, spherical polystyrene divinylbenzene (PS-DVB) resin beads, which can separate molecular weight ranges with exclusion limits from 1,000 Da to an estimated 4 x 10^8 Da. The DRI detector is installed inside of GPC used as mainly concentration detector, therefore, it requires the calibration standards such as polystyrene, polyethylene oxide… before measuring the unknown polymer sample. Additionally, there is a standalone multiangle static DAWN EOS Wyatt light scattering detector connected to GPC, which not only be able to quantify the molar mass of polymer in solution, but also the size/shape of the polymer.
PCO.edge Camera
The pco.edge camera is utilized in conjunction with microscopes to provide data for various materials research relating to colloids and other bio materials. It is a high sensitivity, high resolution camera. The high resolution ensures the data quality, and the sensitivity of the camera allows it to adapt to low light environments, benefiting its use in fluorescence microscopy, since the fluorescence intensity can be very low in certain situations. The camera also provides the capability to take images remotely, with set frame rate or intervals. This allows for time lapse microscope experiment and some extent of fast speed microscopy experiments, from taking pictures with an arbitrary interval up to 100FPS. The acquired grayscale images are put out in series of .tif files, ample for extracting data. This comes in handy for various techniques used in this lab for colloid sciences and material research involving solutions, such as Differential Dynamic Microscopy, which requires input of serial images with time data.
Simultaneous Multi-Angle Light Scattering (SMALS)
The SMALS apparatus is unique in all the world. Built at Georgia Tech around a Wyatt DAWN EOS multiangle light scattering apparatus, it features a 50 mW solid state laser operating at 685 nm, eight channels optimized for static light scattering (SLS) and eight channels for dynamic light scattering (DLS). The SLS channels use traditional Wyatt diode detectors at different angles (XXX-XXX degrees). These detectors are designed to collect spatially incoherent light, as optimal for the SLS experiment. For DLS, eight separate single-mode optical fibers are arranged at various angles. They carry spatially coherent light to 8 Excelitas avalanche photodiode detector modules which in turn drive an ALV wide-range multicorrelator (correlation times of 250 ns to > 1 s). The SLS and DLS detectors operate simultaneously so that evolving systems can be studied (examples: polymerization or degradation of polymer latex particles or silica spheres; attack by antimicrobial peptides on liposomes). Such kinetic light scattering experiments can be conducted with a time resolution of about 125 ms for SLS. For DLS, the kinetic time resolution is dictated by the sample itself but 10-s resolution is achievable in some circumstances. By combining the SLS and DLS data, one can obtain the ratio of gyration to hydrodynamic radius, ρ = Rg/Rh.
Density and Sound Velocity Meter
The density and sound velocity meter is a common tool employed in the beverage industry as well as in the fuels industry. This instruments gives both of its measured parameters with either 6 or 7 significant digits allowing for very precise and accurate measurements of both the density of a solution as well as the speed of sound within a solution. DSA 5000 M is the only instrument that combines density and sound velocity measurements in one setup. It determines the concentration of two- and three-component solutions using the most accurate density results in the market, measured with the Pulsed Excitation Method.
Asymmetric Flow Field Flow Fractionation (AF4)
- Robust separation of macromolecules and nanoparticles from 1 nm to 1000 nm with excellent resolution
- No stationary phase – open channel separation with minimal shear and surface interactions
- Versatile choice of separation channels, permitting sample loads from µL to mL, including semi-preparative FFF
- Optimize separation methods to enhance resolution or size range simply by adjusting flow ratios, even programmatically during a run
- Fractions can be collected and used for off-line analysis (with electron microscopy, MS, ICP-MS, ELISA, etc.)
- Typical analysis times 10 – 30 minutes
- Utilize the fritless column for aggregation-prone samples
- Make use of the highest quality HPLC pumps and autosamplers from Agilent, Shimadzu, Thermo, or Waters
For more information visit Wyatt’s AF4 site.
Gel Electrophoresis
Disk Centrifuge
Measuring the size of particles is important for knowing the uniformity of a sample set. Using a solution gradient, this instrument can separate your samples by their diameter and display the data over a spectrum.
Small Angle Light Scattering
Thermogravimetric Analysis (TGA)
TGA measures the weight of a substance as its heated – you can heat up to temperatures as high as 800 C or even above. By this temperature organic substances burn away completely. TGA can measure weights with great accuracy and is useful in determining the loss of gases at various key temperatures. This provides information about the composition of the material.
Baby Leitz (Kohler Illumination)
Lisa is a versatile polarized and fluorescence light microscope. The old girl was not designed for infinity corrected objectives, but she has been heavily face-lifted with modern light sources. She can be used with modern cameras, usually the Canon EOS 6D but also others are possible. Lisa is delightful and a good choice to practice your Kohler illumination skills (see Kodak book, Photography Through the Microscope).
