The Technical Authority for Pore Analysis
Porosimetry is the analytical measurement of a material's pore size distribution, total pore volume, and surface area. This is the definitive technical resource covering Mercury Intrusion Porosimetry (MIP), Gas Adsorption (BET/BJH), and Capillary Flow Porometry (CFP) — with methodology guides, testing specifications, and interactive calculators aligned to ISO 15901 and ASTM D4284 standards.
Referenced Standards & Frameworks
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Max Pore Diameter (MIP)
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Min Pore Diameter (MIP)
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Core Methodologies
Core Methodologies
Each technique targets a specific pore size regime and provides distinct structural information. Selecting the right method depends on your material type, pore size range, and whether you need total or flow-through porosity data.
Pillar I
Measures macro- and mesopore structures by forcing mercury into a porous material under controlled pressure. Governed by the Washburn equation, MIP provides pore size distribution, total pore volume, bulk and skeletal density, and tortuosity data.
Pillar II
Characterizes micropores and mesopores through physisorption of nitrogen, argon, or krypton gas at cryogenic temperatures. BET theory calculates specific surface area; BJH analysis derives the mesopore size distribution from the desorption isotherm.
Pillar III
Measures only through-pores — the pores that permit fluid transport across a membrane or filter. Based on bubble point theory and Darcy's law, CFP determines mean flow pore size, the largest pore, and the pore size distribution relevant to filtration performance.
Method Selection
The difference between porosimetry and porometry — and between MIP and gas adsorption — is the most common source of confusion in pore characterization. Your choice depends on three factors: pore size range, pore type, and material constraints.
| Parameter | MIP | BET/BJH | CFP |
|---|---|---|---|
| Pore Size Range | 3 nm – 1.1 mm | 0.35 – 300 nm | 13 nm – 500 μm |
| Pore Types | All open pores | All open pores | Through-pores only |
| Surface Area | Estimated | Direct (BET) | Not measured |
| Probe Fluid | Mercury | N₂, Ar, Kr gas | Air / inert gas |
| Destructive? | Yes (Hg contamination) | No | No |
| Key Pitfall | Ink-bottle effect | BET C-constant | Wetting uniformity |
| Primary Standard | ISO 15901-1 | ISO 9277 | ASTM F316 |
Industry Applications
Pore structure directly governs performance — from ion transport in batteries to drug release kinetics in pharmaceutical tablets. Each application demands specific porosity metrics and characterization methods.
Electrode porosity controls electrolyte penetration, ionic conductivity, and rate capability. MIP and BET are used to optimize separator pore structure and electrode calendering parameters.
Catalytic activity depends on accessible surface area and pore transport. BET surface area, BJH mesopore distribution, and micropore analysis via t-plot or DFT methods are critical for catalyst design and deactivation studies.
Tablet dissolution rate, API bioavailability, and controlled-release profiles are governed by pore network connectivity. MIP provides total porosity; gas adsorption reveals surface area of excipient powders.
CO₂ sorbent capacity is a direct function of micropore volume and surface chemistry. BET/DFT analysis determines the capacity of MOFs, zeolites, and activated carbons for carbon capture applications.
Durability, permeability, and freeze-thaw resistance depend on the capillary pore network. MIP is the standard technique for characterizing hydrated cement paste pore structure per ASTM D4284.
Filtration efficiency is determined by the through-pore size distribution. Capillary flow porometry measures bubble point, mean flow pore size, and pore distribution per ASTM F316 for quality control.
Reservoir rock porosity and permeability assessments guide extraction strategy. MIP on core samples provides pore throat distribution, capillary pressure curves, and connectivity data per API RP40.
Tissue engineering scaffolds require controlled pore sizes (100–500 μm) for cell infiltration and vascularization. MIP and micro-CT porometry characterize scaffold architecture to optimize biological response.
Interactive Tool
Convert applied pressure to equivalent pore diameter using the Washburn equation. This is the fundamental relation governing mercury intrusion porosimetry — relating the non-wetting mercury pressure to the cylindrical pore diameter being intruded.
Washburn Equation
d = −4γ cos θ / P
d = pore diameter γ = surface tension of Hg θ = contact angle P = applied pressure
Also available: Unit Converter, BET Surface Area Calculator, and Bubble Point Calculator.
Enter your test parameters below. Default values represent standard MIP conditions (Hg surface tension = 485 mN/m, contact angle = 130°).
Compliance & Standards
All methodology guides on this site are aligned with current international standards. Proper adherence to these standards ensures inter-laboratory reproducibility and data validity.
Evaluation of pore size distribution and porosity of solid materials by mercury porosimetry. Defines procedures for sample preparation, pressure ramp rates, and data interpretation for MIP.
Determination of the specific surface area of solids by gas adsorption using the BET method. Specifies the conditions for valid BET analysis, including P/P₀ range selection and C-constant verification.
Standard test method for determining pore volume distribution of catalysts and catalyst carriers by mercury intrusion porosimetry. Widely applied in petroleum, cement, and materials science.
Standard test methods for pore size characteristics of membrane filters by bubble point and mean flow pore test. The primary standard for capillary flow porometry in filtration QC.
Evaluation of pore size distribution and porosity by gas adsorption. Covers the BJH and DFT methods for determining mesopore and micropore size distributions from adsorption isotherms.
Updated classification of physisorption isotherms (Types I–VI) and hysteresis loops (H1–H5). The authoritative framework for interpreting adsorption data and identifying pore geometry.
Get Started
Download methodology whitepapers or submit a testing inquiry. Our technical documentation covers sample preparation, data interpretation, and error source mitigation for all three methods.
Peer-reviewed technical documents covering the physics, error sources, and best practices for each characterization method.
Submit your material details and we'll recommend the optimal characterization approach and provide a testing estimate.