Problem-solving based on understanding of chemical interaction parameters

It might seem surprising that 3 numbers can describe a vast range of chemical behaviour: polymers, solubility, nanoparticle dispersion, skin permeation, cosmetic formulations, organic photovoltaics, but Hansen Solubility Parameters (HSP) have proven their worth over more than 40 years of practical application. Describing a chemical in terms of dD, its Dispersion characteristics, dP, its Polar property and dH, its H-bonding ability is much more powerful than simplistic (and monodimensional) terms such as "hydrophilic/lipophilic", "polar/non-polar" or parameters such as logP that are so limited in their scope.

In the past few years the power of HSP has been made available via an eBook, software and dataset package Hansen Solubility Parameters in Practice, HSPiP which I have written with Dr Charles Hansen and Dr Hiroshi Yamamoto. Now in its 3rd Edition the package has grown more powerful thanks to the large user community that has suggested additions, provided data and given encouraging feedback that the technique really works over the very wide range of user applications.

I use HSPiP in my own work for real problem-solving and have applied it to classic coating formulations, "greener" solvent cleaning systems, organic photovoltaics, barrier films, nanometre photoresists, Carbon Nanotubes, surfactants, supercritical CO2, skin permeation, cosmetics formulations and pharmaceutical development. HSP aren't magic, they can't solve every problem, but they constantly help me to deliver practical solutions to difficult problems.

To help increase the large database of reliable HSP I'm working with companies that have High Throughput methods for making the key measurements. One example is the HSP-HTS poster (pdf) from an Intelligent Formulation conference showing work with Syntopix and VLCI on measuring HSP with HT techniques.

With Prof Johann Wiechers I produced Formulating for Efficacy, the Software , a new approach for designing effective skin delivery systems for the cosmetics and pharmaceutical industries. Johann was an acknowledged expert in the field of cosmetics delivery and we combined his knowledge with the science of Hansen Solubility Parameters to produce a powerful software package for use by practical formulators. Following his tragic death whilst in Malaysia getting ready to teach a skin delivery course based on FFE, I am now continuing the development of FFE with the active support of key academic experts on skin delivery.

The constant advice and encouragement from Charles Hansen and examples from his vast store of HSP knowledge is very much appreciated. His official site, Hansen-Solubility.com, contains lots more information on HSP and access to HSPiP.

Hiroshi Yamamoto ("ChemNeuro") is a constant source of algorithms that have hugely expanded the utility of HSPiP. His lively Pirika site takes an unconventional and experimental approach to HSP matters.

The powerful COSMOtherm package from COSMOlogic is an alternative way of looking at solubility issues. Because HSPiP and COSMOtherm each have their areas of particular strength and applicability I am happy that there is close scientific cooperation between myself and Dr Andreas Klamt and his team at COSMOlogic which we believe will help widen the use of solubility-based thinking across academia and industry.