Our goal is to provide soft matter characterization tools and expertise so you can be successful in your project. You can find helpful information below on soft matter basics and their properties and SM Core Lab characterization capabilities. Feel free to contact our staff for additional information or you can make a reservation through our web-based iLab core facilities management platform.
Full-service Sample Analysis
Let our staff analyze your sample(s) for you. Submit your request with your sample and test requirements and sit back and relax. We’ll take care of the rest.
Sample submissions are processed in a first-come-first-serve basis unless otherwise requested. Samples may be dropped off in the dropbox located outside the SM Core lab or hand delivered to a lab member. If needed, you may ship your samples to the address listed in our Contact webpage.
Complete the form below before submitting your sample for analysis. A staff member will contact you within 24 hours to discuss the details of your submission.
Training
An instrument-specific basic operation and safety training is required before customers can utilize the Instrument Self-Use service. You may also request advanced training tailored to your application from our expert staff.
Training can be scheduled for Monday – Friday between 9am – 5pm.
Self-Serve Instrument Time
After an initial instrument-specific operation and safety training, customers can book time with the instrument to perform their own analyses. Sample preparation and analysis tools and supplies are available for your use in the laboratory.
Open access to instrumentation is available for all UNC and non-UNC customers. UNC students and employees can access the lab 24/7 using their OneCard. All others can schedule time with the instruments during regular business hours (Monday – Friday, 9am – 5pm).
** Data processing software available to our customers upon request through our contact form.
- The TA Instruments DMA/Rhe, DSC, and TGA instruments utilize the TRIOS operating and data processing software (Windows OS only).
- Offline processing of MALDI-ToF spectrum is possible through the FlexAnalysis software (Windows OS only).
Soft Matter Characterization in the SM Core Lab
Visit the INSTRUMENTS webpage for information on instrument specifications and features.
MALDI-ToF/TOF MASS Spectrometry:
The Bruker UltrafleXtreme III MALDI-ToF/ToF is a highly sensitive mass analyzer that can analyze a wide range of molecules with molecular weights of 600 to 40K daltons (high resolution reflectron mode) and as high as 500K daltons (linear mode). The technique involves the irradiation of co-crystallized sample and matrix material to form positive or negative species with mass(es) of [M + H]+ and [M – H]-, respectively, through a “soft ionization” mechanism involving a proton transfer from the matrix to the sample or deprotonation of the sample by a basic matrix.
Gel Permeation Chromatography (GPC) has been a standard for molecular weight determination of synthetic polymers for decades, but has limitations. MALDI-ToF has emerged as a very powerful technique that not only address most of GPC’s limitations, but also offer superior sensitivity, mass accuracy, mass resolution, solvent compatibility, and analysis mass range. The table below shows a comparison of the two methods for molecular weight determination of soft matter.
| GPC | MALDI-ToF-ToF (Bruker Ultraflextreme) | |
|---|---|---|
| Mass resolution | GPC separates samples based on exclusion or inclusion into the pores of the stationary phase resin which lead to broad peaks that envelope a molecular weight range of the polymer oligomers (i.e. polymer distribution). | Very sharp peaks with n-mer baseline mass resolution of polymers having m/z<40K daltons (reflection mode). M/Z masses are reported where M is the absolute mass of the ion species and Z is the ionic charge number. |
| Mass determination and mass accuracy | Sample runs are compared against a MW calibration curve. Relative MWs sample species can be calculated with typical accuracy of +/- 5%. | Masses reported are absolute mass with mass accuracy of 1.5ppm (1 ppm = 10E-6 = 0.0001%) |
| Upper mass limit | ≈150K | ≈600K |
| Analysis time | Typical is 30 – 60 minutes per sample or calibrant run. | <3 minutes per sample |
| Sample/solvent solubility | All components of the sample MUST be soluble in the mobile phase. | The sample does not need to be soluble in a solvent. However, the analytes(s) MUST be ionizable. |
| Solvent use per analysis | Typically between 50mL – 200mL. | Sample mixtures are prepared by combining stock solutions of sample, matrix, and ionizing agent. 1 – 2uL of the sample mixture is used for each analysis. |
| Calibrants | Because GPC/SEC separates according to hydrodynamic volume and not molar mass, only apparent molar masses (related to the calibration standards) are obtained if the calibration standards and the samples are chemically or structurally different. | The calibrants and sample do not need to match. Can use any ionizable calibrant(s) with known molecular weight(s). |
| Determination of molecular mass averages (Mn, Mw), polydisperity, and degree of polymerization | Only provides an approximate molecular weight distribution as the technique measure hydrodynamic volume versus actual molecular weight. However, hydrodynamic volume is not always the same for every polymer and thus can introduce error when molecular weight standards and samples do not match. | Provides absolute molecular weights with n-mer resolution* that are used to determine molecular weight averages directly with high degree of accuracy. |
| Polymer structure information | Not possible. | Provides n-mer resolution* that allow repeating unit, end group, and composition determinations and elucidation of polymer mixtures with similar molecular weights. |
| Ease of method development and change of solvent system | Can be time and effort extensive to change solvent systems. Runs are long so methods development is tedious and time consuming as well. | No instrument configuration changes are necessary. Only the sample preparation method is modified. The short analysis time and the use of large capacity sample target plates allows for very fast method development. |
Thermal Analysis:
The Soft Matter Characterization lab has two thermoanalytical tools, the TA Instruments Differential Scanning Calorimeter (DSC) DSC250 and the TA Instruments Thermogravimetric Analyzer (TGA) TGA5500. DSC can provide accurate measurement of temperature and magnitude of phase transitions and heat capacities and allows the determination of sample impurity based on the Van’t Hoff law of melting point depression of eutectic systems. The DSC250 is a highly sensitive instrument that enable the detection of weak phase transitions and is able to separate overlapping thermal transitions that may be present in multi-component or complex samples using the modulated DSC (mDSC) feature . The TGA is a high precision, sensitive, and reliable weight balance that helps understand a material’s mass change over time and temperature and calculates weight loss due to chemicals, material breakdown, ash content, carbon black, and moisture. It can also be used to detect interactions between substances, active compounds, and packaging materials in controlled environments.
Rheometry:
The TA Instruments HR30 is a hybrid Dynamic Mechanical Analyzer (DMA) and Rheometer. Rheometry studies the flow and deformation of viscoelastic materials and the interrelation between force (applied stress), deformation, and time. The HR30 is a high-precision rheometer that can be used for characterizing non-Newtonian materials with viscosity and modulus measurements for behaviors like shear thinning, thixotropy, and yield stress of complex fluids (emulsions, suspensions, paints, inks, coatings, slurries) and measuring material viscoelasticity (Storage Modulus, Loss Modulus, Tan Delta). The EVA accessory can be used for extensional viscosity measurement of solid samples. There are many commercially available accessories and geometries for the HR30 through TA Instruments and each provides specific measurements for a wide range of applications. Below is a list of rheology accessories and geometries available for customer use in the SM Core Lab.
- Environmental Test Chamber (ETC)
- ETC Parallel Plates
- Advance Peltier System (APS)
- Extensional Viscosity Accessory (EVA)/Sentmanat Extension Rheometer Universal Testing Assembly (SER3)
- UV Curing Accessory
- Peltier Solvent Trap and Evaporation Blocker
- Peltier Immersion Cup
- Plates and Cones (40mm/1Deg cone, 40mm plate, 40mm APS plate, 25mm parallel plate, 20mm sandblasted plate, 20mm sandblasted APS plate, 8mm plate, 8mm stepped plate)
Mechanical testing:
The TA Instruments HR30 is also capable of linear dynamic mechanical testing (DMA) of soft matter. DMA is used to characterize a material’s properties as a function of temperature, applied stress, time, frequency, and environment or a combination of these parameters. The HR30 has a patented axial DMA capability that permit amplitude-controlled oscillatory deformation in the axial direction that provides a direct measure of the modulus of elasticity, or Young’s Modulus (E), when used with the torsion/tension assembly. The HR30 DMA mode can also be used for identifying a material’s transition temperatures over a wide range of temperatures using the ETC module. The EVA/SER3 assembly is an innovative accessory that was first developed by Dr. Martin Sentmanat during his work at The Goodyear Tire & Rubber Company and is now manufactured by Xpansion Instruments. It consists of two rotating drums that allow for uniform extensional deformation during measurement. Measurements such as solids tensile testing, tear testing, peel testing, and high-rate fracture testing are possible and can be used with the HR30’s environmental test chamber. Below is a list of mechanical test accessories available for customer use in the SM Core Lab. Please see the TA Instruments HR30 brochure for a complete listing of DMA accessories available.
- Environmental Test Chamber (ETC)
- Torsion Rectangle of Film/Fiber Tension Assembly
- Extensional Viscosity Accessory (EVA)/Sentmanat Extension Rheometer Universal Testing Assembly (SER3)
Universal testing machines such as the Instron 34SC-1 Universal Mechanical Tester combines electromechanical and hydraulic systems to accomplish tests such as tensile, compression, bend, peel, tear, shear, friction, puncture, fatigue, and other mechanical tests. There are a number of accessories commercially available that are especially configured to perform each test. The Instron 34SC-1 has a maximum force capacity of 1kN and a vertical test space of 41 inches which is ideal for testing viscoelastic materials. Below is a list of mechanical test accessories and load cells available for customer use in the SM Core Lab.
- 1kN load cell
- 1N load cell
- Pneumatic clamps with rubber serrated or flat jaw attachments