Porosity and Surface Area
Characterizing the total surface energy profile of a solid is a useful tool for comparing the performance of similar materials. It also provides a good starting point for estimating numerous other physicochemical properties such as aggregation likelihood, flowability, etc. However, it is important to differentiate between a solids contributions to this total surface energy, which is split into dispersive and specific contributions.
Assessment of a surface’s specific energy indicates its polarity and its tendency to interact with polar solvents and charged bodies. Key physiochemical properties such as wettability can be estimated using this measure. Further study can determine if a surface displays more acid or basic character which can be vital in determining a material’s functionality.
BET Surface Area
Dynamic Vapor Sorption (DVS) instruments and Inverse Gas Chromatography Surface Energy Analyzer (iGC-SEA) can be used for the determination of BET surface areas. Both instruments can carry out experiments at room conditions and need very small sample amounts (typically a few milligrams for the DVS). This compares to the traditional nitrogen BET method, which requires very low experimental temperatures and sample sizes of typically one gram. Some samples may change their morphology at low temperatures. While this is an issue for traditional BET methods, this ceases to cause any issues using iGC or DVS because they test at room temperature.
Notes:
Application Note 18: Measuring BET Surface Areas using Organic Probe Molecules | Request a copy
Application Note 225: Isotherm Measurements for BET Surface Area Calculations using Inverse Gas Chromatography | Request a copy
Catalysts
Finite concentration Inverse Gas Chromatography (IGC) is a useful tool for the investigation of surface and pore properties. The Surface Energy Analyzer (SEA), an instrument based on the principles of IGC, together with thermal desorption data from Dynamic Vapor Sorption (DVS), provides the possibility to separate micropore adsorption from surface adsorption and mesopore adsorption. This allows the calculation of BET values with physical relevance in highly microporous materials and the consideration of molecular sieve effects.
Notes:
Application Note 215: A Sorption Study on Microporous Materials by Finite Dilution Inverse Gas Chromatography | Request a copy
Nanomaterials
Surface energy is an important property in numerous industrial applications and processes. It shows a strong dependency on various macroscopic properties and relates to many crucial interfacial phenomena, for example, adhesion and wetting behaviors. Nanomaterials can be energetically inhomogeneous, exhibiting various surface sites, such as structural defects or specific functional groups. Therefore, a surface energetic heterogeneity profile can provide more comprehensive information on the nature and population of these surface sites. Inverse Gas Chromatography is a sensitive, quick, and reliable way of characterizing nanomaterial surface properties.
Notes:
Application Note 226: Surface Energetic Heterogeneity of Carbon-based Nanomaterials | Request a copy
Porous Materials
Many common materials contain pores and pore networks, which can greatly impact material behavior in natural and engineered materials. These include Metal Organic Frameworks (MOFs), Covalent Organic Frameworks (COFs), and zeolites. They are great candidates for absorbents, catalysts, and separation processes. Dynamic Vapor Sorption (DVS) and Inverse Gas Chromatography (IGC SEA) can be valuable techniques in detecting and characterizing porosity in these materials.
Notes:
Application Note 51: Gas Capture and Vapour Separation by Microporous Materials | Request a copy
Application Note 54: Detecting and Modelling Porosity in Natural and Engineered Materials | Request a copy
Application Note 215: Characterisation of Microporous Materials by Finite Concentration Inverse Gas Chromatography | Request a copy
Application Note 504: Water Vapor Induced Mesoporous Structure Collapse Observed by GenRH with Mcell and FT-IR | Request a copy
Determining porosity and surface area with DVS & iGC
Our range of DVS & iGC products are well suited to study porosity and surface area. View the range using the link below to find out more about which instrument is right for you.