One of the main themes in SAFN is to correlate the functions of materials with their nanostructures. Hence, advanced facilities for nanostructural characterization including a variety of microscopic (electron and optical) and scattering (light, X-ray and neutron) techniques are key components here. At SAFN, the probing length scale constantly ranges from Å to micron.
- Feature: The ALV CGS 3MD is a compact goniometer system with 4 detectors, each being 32 degrees apart from each other, covering a wide range of scattering angles from 20 to 155 degrees. The laser source has a power of 22 mW and produces a wavelength of 632.8 nm. Both static and dynamic light scattering (SLS and DLS) measurements can be performed at this machine. For SLS, the probing range of the particle sizes (radius of gyration) is between 30 nm and microns. It can also provide the information of molecular weight, MW (or aggregation number) and second Virial coefficient (A2). For DLS, the probing range of hydrodynamic radius is from 2 nm to several hundred nm through Stokes-Einstein relationship (assuming spherical particles). The detailed description of the instrument can be found in ALV website.
- Limitations: transparent solutions (better colorless), low resolution in shape and morphology.
- Feature: A NSF-MRI (Major Research Instrument) funded SAXS instrument (Bruker Nanostar) is available at IMS, UCONN for nanostructural characterization of the materials. The Nanostar includes the capability of SAXS, WAXS, X-ray reflectometry and GI-SAXS measurements. The attainable minimum q (scattering vector) is 0.05/nm, which renders a probing range from 100 nm to several Å. The X-ray source is Bruker’s most advanced rotating anode source (TXS, Turbo X-ray Source) with a brilliance of 1.2 x 10^8 photons/s. The applicable sample stages includes temperature-controlled stage (between 120 and -30 degree C), flow cell, in-situ tensile stage and rheometer. The required sample amount for testing is ~ 60 micro liter. The detecting system is Bruker’s high-resolution 2-D VÅNTEC-2000 detector (pixel size: 68 micron x 68 micron). More details can be found on Bruker’s website about Nanostar. the Nanostar will be able to resolve morphologies of proteins, lipids, surfactants , polymers, gels and nanoparticles, nanoscaled defects (void) in the materials.
- Limitations: The contrast of the measurements depends on the electron density difference between the object and its host matrix, which may not always be significant enough for detection. The strong absorption of X-ray sometimes requires a short path-length of the sample.
- Feature: The NANO DSC allows us to detect the phase transition temperatures of solution samples. The sensitivity of NANO DSC is enhanced via using capillary cells (instead of traditional “pan”) and can go as low as 20 micro-g of the sample (e.g., proteins, lipids etc.). The detailed information is described at the TA instrument website for NANO DSC. A degassing station is also available in the lab to degas the samples thus ensuring a flat baseline.
- Feature: The Olympus BX-51 has the optimal features of optical microscopy, which can perform darkfield, brightfiled, DIC, phase contrast, polarized and fluorescence measurements. A Linkam stage can also be installed at the sample position to control the temperature. Please refer to Olympus BX-51 for details.
- Feature: At IMS, UCONN there are several EM instruments accessible for students and faculty for research purpose. Please refer to the link for details.
- Feature: The IMS has a steady-state fluorescence spectrometer (FluoroLog-3) which allows us to obtain the fluorescence spectra effectively.
- Feature: The BI-DNDC allows us to measure the differential refraction with concentration of a sample. This information is required to obtained the accurate MW via SLS data. The wavelength used in this instrument is 620 Å close to the wavelength used in our ALV -CGS 3MD system.
Brookhaven Instruments – DNDC