The Polymer Characterization Facility at Brown University was established in 2009 under the auspices of the Bioengineering Core Facility. Operating at the interface between polymer science and biology, our experts can develop and fully characterize novel polymeric drug delivery systems for controlled release and tissue engineering applications. Additionally, the following list of specialized instrumentation allows us to provide an array of services for the physical characterization of polymers and biomaterials.
- Differential Scanning Calorimeters (DSC)
- Fourier Transform Infrared Spectrometer (FTIR)
- High Performance Liquid Chromatography (HPLC)
- Gel Permeation Chromatography (GPC)
- Laser Diffraction Particle Size Analyzer
- Ultraviolet-Visible Spectrophotometer (UV-VIS)
- Dynamic Mechanical Analyzer (DMA)
- Dynamic Contact Angle Analyzer (DCA)
- DIFFERENTIAL SCANNING CALORIMETERS (DSC): Thermal analysis is a term used to cover a group of techniques in which a physical property of a substance and/or its reaction product(s) is measured as a function of temperature. DSC measures the heat required to maintain the same temperature in the sample versus an appropriate reference material in a furnace. DSC can measure a number of important physical changes in a polymer—these include the glass (Tg) and melting (Tm) transition temperatures, crystallization temperature (Tc), and the degradation or decomposition temperature (TD). Chemical changes due to polymerization reactions, degradations reactions, and other reactions affecting the sample can be determined.
- FOURIER TRANSFORM INFRARED SPECTROMETER (FTIR): Infrared spectroscopy is based on the fact that molecules have specific frequencies at which they rotate or vibrate. Complex molecules have many bonds leading to infrared absorptions at characteristic frequencies that may be related to chemical groups. FTIR is a popular method for characterizing polymers—it may be used to identify the composition of certain functional groups in a molecule, to monitor polymerization processes, to characterize polymer structures, to examine polymer surfaces, and to investigate polymer degradation processes.
- HIGH PERFORMANCE LIQUID CHROMATOGRAPHY (HPLC): HPLC is a type of column chromatography used in analytical chemistry to separate, identify, and quantify compounds. HPLC utilizes a stationary phase (a column which is composed of chromatographic packing material), a pump which moves mobile phase through a column, and a detector which shows the retention times of the molecule(s) being analyzed. Depending on the type of column and solvents that are utilized, a molecule will interact with the stationary phase producing varied retention times.
- GEL PERMEATION CHROMATOGRAPHY (GPC): Also termed Size Exclusion Chromatography (SEC), GPC is a separation method for polymers and also provides a relative molecular weight distribution. GPC can be used for routine polymer characterization and quality control, particularly in determinations of molecular weight distribution (MWD). It is extremely valuable for both analytical and preparative work with a wide variety of systems ranging from low to very high molecular weights. This method can be applied to a wide variety of solvents and polymers, depending on the type of column used.
- LASER DIFFRACTION (LS) PARTICLE SIZE ANALYZER: The LS uses reverse Fourier lens optics incorporated in a patented binocular lens system. This enables the LS to optimize light scattering across the widest dynamic range in a single scan. It incorporates Enhanced Laser Diffraction technology and PIDS (Polarization Intensity Differential Scattering), to rapidly determine particle size distribution of materials in a wet and dry state with particles in the size range 0.02 to 2000 micron.
- ULTRAVIOLET-VISIBLE SPECTROPHOTOMETER (UV-VIS): UV-Vis spectroscopy is used in the quantitative determination of organic compounds which absorb light in the UV or visible regions of the electromagnetic spectrum. The absorbance of a solution is directly proportional to the concentration of the absorbing species in the solution.
- SPECTROFLUOROPHOTOMETER: Fluorescence is used to identify or quantify specific molecules in complex mixtures. If the compound of interest is not fluorescent by itself, it can be labeled with specific fluorescent probes. Fluorescence spectrometry can be as much as thousands of times more sensitive than absorbance techniques. This makes it possible to analyze samples in the nanogram to picogram range.
- DYNAMIC MECHANICAL ANALYZER (DMA): Dynamic mechanical analysis provides a method for determining elastic and loss moduli of polymers as a function of temperature, frequency or time, or both. Viscoelasticity describes the time-dependent mechanical properties of polymers, which in limiting cases can behave as either elastic solids or viscous liquids. Knowledge of the viscoelastic behavior of polymers and its relation to molecular structure is essential in the understanding of both processing and end-use properties. DMA can be applied to a wide range of materials—this procedure can be used to evaluate the degree of phase separation in multicomponent systems; the amount, type, and dispersion of filler; the degree of polymer crystallinity; and the stiffness of polymer composites.
- DYNAMIC CONTACT ANGLE ANALYZER (DCA): The DCA Radian Analyzer offers powerful and versatile approaches to the comprehensive understanding of the complex interactions at liquid-liquid and liquid-solid surfaces. A unique contact angle hysteresis curve is produced by the microbalance as it measures the force exerted by the moving contact angle in advancing and receding directions. The DCA can be used to improve adhesion or to apply a coating or modify a surface plate.
The Polymer Characterization Facility at Brown University offers an array of services for the Brown community and industry alike. The cost of these services is dependent on the type of service, the materials utilized, and the time required to perform the service. Please contact Stacia Furtado for more information.