- Surface Area & Gas Adsorption
- Pore Size
- Representative Sampling
- Particle Size
- Particle Shape
- Dynamic Vapor Sorption (DVS)
- Zeta Potential
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Pore Size Distribution and Analysis
Quantachrome offers instruments for determining pore size by electroacoustics, capillary flow porometry, mercury porosimetry and gas adsorption.
The choice of method depends on the type of pores and the expected pore size, generally with gas sorption being suitable for micro to meso pores, mercury porosimetry for meso to macro pores and flow porometry for most through pores. In practice the structures can contain many different types of pores requiring more than one analytical approach. With the introduction of electroacoustics, mean pore size can be determined very rapidly without mercury, cryogens or vacuum pumps.
Electroacoustics uses an electrokinetic phenomenon called the seismoelectric effect to determine the mean pore size of a material. When high frequency ultrasound is applied to a wetted porous material the resulting electroseismic current is dependent on the capacitance effect of the double layer as well as how they overlap in pores. To make the measurement, the material is fully wetted with a suitable liquid (depending on the type of sample) and can return results in a few minutes.
Read more about Electroacoustics
Capillary Flow Porometry
Capillary flow porometry, also know as the liquid expulsion technique, uses the simple principle of gas pressure to force a wetting liquid out of through-pores in a sample. Through pores are simply those that connect from one side of the sample to the other. The pressure at which pores empty is inversely proportional to the pore size, larger pores require a lower pressure than do smaller pores. The resulting volumetric flow of gas through emptied pores is also measured. Pore size is calculated using the Washburn equation.
Read more about Capillary Flow Porometry
The operation of all mercury porosimeters is based upon the physical principle that a non-reactive, non-wetting liquid will not penetrate fine pores until sufficient pressure is applied to force its entry. The relationship between the applied pressure and the pore diameter into which mercury will intrude is given by the Washburn equation.
Read more about Mercury Porosimetry
Pore size determination by gas sorption requires a recognition and understanding of different basic isotherm types. IUPAC Classification recognizes six types of Sorption Isotherms, and the pore size distribution can be calculated from the adsorption or desorption branch of the isotherm. In some cases the desorption curve does not follow the adsorption curve creating the so called hysteresis adding more information about the pore structure.
The interpretation of these isotherms and the use of the appropriate models:
NLDFT, QSDFT, Monte-Carlo, t-plot, alpha-s method, MP method, DR & DA methods, BJH, DH, all included in Autosorb-iQ, Nova and Quadrasorb Series of instruments yield information about the pore structures, pore volume and pore size distribution.
The tendency of all solid surfaces to attract surrounding gas molecules gives rise to a process called gas sorption. Monitoring the gas sorption process provides a wealth of useful information about the characteristics of solids such as surface area and pore size. Surface area is calculated from the monolayer amount, often using the BET method, and pore size is calculated from pore filling pressures.
Read more about BET Surface Area & Gas Adsorption
For more information contact us.
Pore Size Research Papers
Review recent papers citing use of Quantachrome pore size instruments:
TITLE: Nanosized metal–organic framework of Fe-MIL-88NH2 as a novel peroxidase mimic and used for colorimetric detection of glucose
AUTHORS: Ya Li Liu, Xi Juan Zhao, Xiao Xi Yang and Yuan Fang Li - Southwest University, China
USAGE: pore size and pore volume were determined by N2 adsorption-desorption isotherms obtained at 77 35 K
TITLE: Hierarchically structured bioactive foams based on polyvinyl alcohol–sepiolite nanocomposites
AUTHORS: Wicklein, Aranda, Ruiz-Hitzkya, Darder - Instituto de Ciencia de Materiales de Madrid, CSIC, Spain
USAGE: pore size distribution of the foams was measure by using a mercury intrusion porosimeter
TITLE: A method for pore size and porosity analysis of porous materials using electroacoustics and high frequency conductivity
AUTHORS: Dukhin, Swasey and Thommes - Colloids and Surfaces A: Physicochemical and Engineering Aspects
INSTRUMENT: Wave 3805
USAGE: porosity determination via conductivity measurements have been performed
TITLE: Mechanically Robust Polyurethane Microfibrous Membranes Exhibiting High Air Permeability
AUTHORS: Jianfeng Ge, ikifa Raza, Fu Fen et al - Donghua University, China
INSTRUMENT: Porometer 3G
USAGE: pore structure of the membranes was analyzed using bubble point method
TITLE: Fractal porosity in metals synthesized by a simple combustion reaction
AUTHORS: Gomez-Romero, Julio and Ballesteros
USAGE: Pore size analyses were carried out in a Porosimeter … which analyzes pore volume of 15 pores with diameter between 0.0070-400microns by intrusion between 5% to 95% of 0.5 cc of Hg
TITLE: Optimization of a lime-based sorbent for carbonation at low temperature enhanced by water vapor
AUTHORS: Pacheco, Voga, de Lima, Belchior - Universidade Federal de Minas Gerais, Brazil
USAGE: Preliminary N2 adsorption analyses were carried out in pellets of synthesized samples … and it was applied 22 nitrogen adsorption/desorption cycles in order to determine the surface area and the pore size distributions
TITLE: Enhanced performance of a macroporous ceramic support for nanofiltration by using α-Al2O3 with narrow size distribution
AUTHORS: Hong Qi, Shufeng Niu, Xiaoluo Jiang, Nanping Xu - Nanjing University of Technology, China
USAGE: Pore size distribution of support was measured by mercury intrusion method
TITLE: Zeolite-templated IrxRu1−xO2 electrocatalysts for oxygen evolution reaction in solid polymer electrolyte water electrolyzers
AUTHORS: Guangfu Li, Hongmei Yu, Wei Song et al - Chinese Academy of Sciences, China
USAGE: physical surface area and pore size distribution were determined by N2 gas absorption/desorption measurements
TITLE: Influence of printing parameters on the transformation efficiency of 3D-printed plaster of paris to hydroxyapatite and its properties
AUTHORS: Suwanprateeb, Thammarakcharoen, Wasoontararat, Suvannapruk -National Metal and Materials Tech Center, Thailand
USAGE: Pore size and porosity in the converted samples at each period were determined using mercury porosimetry analyzer
TITLE: Targeted Thrombolysis by Using of Magnetic Mesoporous Silica Nanoparticles
AUTHORS: Wang, Mingqi; Zhang, Jixi; Yuan, Ziming; Yang, Wenzhi; Wu, Qiang; Gu, Hongchen
USAGE: pore size distributions were derived from the desorption branch of the isotherms by the NLDFT method