Spectroscopic analysis suite: NMR & FT-IR
NMR spectroscopy (NMR) is an information rich, non-destructive analytical technique that provides detailed information about molecular structure and polymer composition, allows the observation of polymerisation reactions and quantitative determination of molecular weights. RCSI Chemistry houses a fully automated Bruker DPX-400 NMR spectrometer (400 MHz) with the ability to analyse typical nuclei (1H, 13C, 19F and 31P) and perform a wide range of 1D and 2D experiments.
Like NMR spectroscopy, attenuated total reflection (ATR) FT-IR spectroscopy is a non-destructive analytical tool which provides information of molecular functionality and limited structural data. The Heise Lab utilises a ThermoFisher Nicolet iS10 FT-IR spectrometer with an optimised spectral range of 7800 - 350 cm-1.
GPC/SEC is an essential chromatographic technique in order to determine the molecular weight and molecular weight distribution of polymeric materials. The Heise group operate 2 GPC/SEC systems with varying eluents.
A PSS SECurity GPC system equipped with a PFG 7 µm 8 × 50 mm pre-column, a PSS 100 Å, 7 µm 8 × 300 mm and a PSS 1000 Å, 7 µm 8 × 300 mm column in series and a differential refractive index (RI) detector. The eluent is 1,1,1,3,3,3-Hexafluoro-2-propanol (HFiP) containing 0.02M NaTFAc.
An Agilent 1200 system equipped with two PSS GRAM analytical (8 x 300 mm and 8 x 100 mm, 10 μm) columns in series and a differential refractive index detector. The eluent is dimethylformamide (DMF) containing 0.01 M LiBr.
Thermal analysis suite: DSC/TGA
DSC and TGA analysis is used to determine key thermal properties of polymeric materials such as degradation, melting, crystallisation and glass transition temperatures as well as water content and polymer composition.The Heise group thermal analysis suite consists of a TA Instruments DSC Q200 and TGA Q50.
The DSC Q200 system is equipped with a chiller unit and has a working temperature range between -80 - 725 °C under a nitrogen or standard atmosphere. The TGA Q50 system has a working temperature range between ambient room temperature to 1000 °C.
Owing to the Heise groups interest in micro- and nano- materials, our dynamic light scattering (DLS) unit is an essential piece equipment for the day-to-day analysis of particle size. In addition to DLS, trained members of the Heise group have access to transmission electron microscopy (TEM) and nanoparticle tracking analysis (NTA) facilities.
DLS analysis is performed using a Malvern Zetasizer Nano ZSP, which can also be utilised to analyse particle zeta potential (laser Doppler micro-electrophoresis) and molecular weight (Static lisght scattering (SLS)).
TEM images are recorded on a Hitachi H-7650, while NTA is conducted on a NanoSight NS300
Mechanical analysis: rheometry & tensiometry
The Heise group has a keen interest in the development of hydrogels and mechanically robust polyesters for biomedical applications such as 3D printing, tissue engineering and implantable biomaterials. As such, it is important that mechanical properties such as Young's modulus, viscoelastic behaviour and sheer strength are well defined.
For analysis of thermoplastics, elastomers and covalent crosslinked gels, we employ a Tensiometric M100-1CT system with a load cell capacity of 1 kN and adjustable heads for traditional tensile and compression analysis. When analysing physically crosslinked gels, bioinks or determining gel points of covalently crosslinked gels we utilise an Anton Paar MCR 301 digital rheometer fitted with adjustable plates, UV curing stage and chiller.