Imperial College London


Faculty of EngineeringDepartment of Chemical Engineering

Reader in Particle Technology



+44 (0)20 7594 0784jerry.heng




417AACE ExtensionSouth Kensington Campus






BibTex format

author = {Shah, UV and Olusanmi, D and Narang, AS and Hussain, MA and Gamble, JF and Tobyn, MJ and Heng, JYY},
doi = {10.1016/j.ijpharm.2014.06.014},
journal = {International Journal of Pharmaceutics},
pages = {140--147},
title = {Effect of crystal habits on the surface energy and cohesion of crystalline powders},
url = {},
volume = {472},
year = {2014}

RIS format (EndNote, RefMan)

AB - The role of surface properties, influenced by particle processing, in particle–particle interactions (powder cohesion) is investigated in this study. Wetting behaviour of mefenamic acid was found to be anisotropic by sessile drop contact angle measurements on macroscopic (>1 cm) single crystals, with variations in contact angle of water from 56.3° to 92.0°. This is attributed to variations in surface chemical functionality at specific facets, and confirmed using X-ray photoelectron spectroscopy (XPS). Using a finite dilution inverse gas chromatography (FD-IGC) approach, the surface energy heterogeneity of powders was determined. The surface energy profile of different mefenamic acid crystal habits was directly related to the relative exposure of different crystal facets. Cohesion, determined by a uniaxial compression test, was also found to relate to surface energy of the powders. By employing a surface modification (silanisation) approach, the contribution from crystal shape from surface area and surface energy was decoupled. By “normalising” contribution from surface energy and surface area, needle shaped crystals were found to be ∼2.5× more cohesive compared to elongated plates or hexagonal cuboid shapes crystals.
AU - Shah,UV
AU - Olusanmi,D
AU - Narang,AS
AU - Hussain,MA
AU - Gamble,JF
AU - Tobyn,MJ
AU - Heng,JYY
DO - 10.1016/j.ijpharm.2014.06.014
EP - 147
PY - 2014///
SN - 1873-3476
SP - 140
TI - Effect of crystal habits on the surface energy and cohesion of crystalline powders
T2 - International Journal of Pharmaceutics
UR -
UR -
VL - 472
ER -