Surface area & porosity

Edited: Adi Ben-Yaakov

Surface area and porosity are important physical properties that influence the quality and utility of many materials and products. Therefore, it is critically important that these characteristics be accurately determined and controlled. Likewise, knowledge of surface area and especially porosity often is an important key to understanding the formation, structure, and potential application of many natural materials

Porosity is defined as the ratio between the void volume of a porous material (substrate) and the total material volume. The term porosity is used in many fields including geology and earth sciences, soil hydrology and physics, agriculture and irrigation, soil mechanics and building foundations, materials engineering and metrology, tissue engineering and medicine.

Porosity and surface area have a decisive effect on processes such as water flow within the porous substrate, movement of solutes and particles, chemical reactions and mass and heat transfer phenomena, thermal insulation, flexibility and resistance to loads and stresses.

Additive Manufacturing
Surface area is a critical tool in investigating the kinetics of the sintering process and product properties. Particles having rough surfaces or internal porosity will generally exhibit higher specific surface areas. Therefore, surface area indicates the amount of sample surface available to react with other component particles and /or the surrounding environment

Adsorbents
Knowledge of surface area, total pore volume, and pore size distribution is important for quality control of industrial adsorbents and in the development of separation processes. Surface area and porosity characteristics affect the selectivity of an adsorbent.


Activated Carbons
Surface area and porosity must be optimized within narrow ranges to accomplish gasoline vapor recovery in automobiles, solvent recovery in painting operations, or pollution controls in wastewater management


Catalysts
The active surface area and pore structure of catalysts influence production rates. Limiting the pore size allows only molecules of desired sizes to enter and exit, creating a selective catalyst that will produce primarily the desired product.


Carbon Black - Wears
The wear lifetime, traction, and performance of tires are related to the surface area of carbon blacks used in their production


Ceramics
Surface area and porosity affect the curing and bonding of greenware and influence the strength, texture, appearance, and density of finished goods. The surface area of glazes and glass frits affects shrinkage, crazing, and crawling.


Nanotubes
Nanotube surface area and microporosity are used to predict the capacity of a material to store hydrogen.


Pharmaceuticals
Surface area and porosity play major roles in the purification, processing, blending, tableting, and packaging of pharmaceutical products as well as their useful shelf life, dissolution rate, and bioavailability.


Medical Implants
Controlling the porosity of artificial bone allows it to imitate real bone that the body will accept and allow the tissue to be grown around it.


Paints and Coatings
The surface area of a pigment or filler influences the gloss, texture, color, color saturation, brightness, solids content, and film adhesion properties. The porosity of a print media coating is important in offset printing where it affects blistering, ink receptivity, and ink holdout.

Dr. Golik Scientific Solutions provides consulting options, measurement, and systems for measuring surface area and porosity, with suitability for the application you are required to measure, the Department of Physical Characterization of Materials is a backbone of knowledge and experience and can be contacted for examining solutions on the website www.golik.co.il