Complex formation in solutions of oppositely charged polyelectrolytes at different polyion compositions and salt content

The formation of complexes in solutions containing positively charged polyions (polycations) and a variable amount of negatively charged polyions (polyanions) has been investigated by Monte Carlo simulations. The polyions were described as flexible chains of charged hard spheres interacting through a screened Coulomb potential. The systems were analyzed in terms of cluster compositions, structure factors, and radial distribution functions. At 50% charge equivalence or less, complexes involving two polycations and one polyanion were frequent, while closer to charge equivalence, larger clusters were formed. Small and neutral complexes dominated the solution at charge equivalence in a monodisperse system, while larger clusters again dominated the solution when the polyions were made polydisperse. The cluster composition and solution structure were also examined as functions of added salt by varying the electrostatic screening length. The observed formation of clusters could be rationalized by a few simple rules.

Globalization, new ecologies, new zoologies and the purported death of the eclectic paradigm

This paper provides a commentary to John Mathews' article in issue 23(1) of the Asia Pacific Journal of Management. I discuss how globalisation is fundamentally altering the milieu within which international business is conducted, and this new ‘ecology’ may indeed require scholars to consider a new ‘zoology’ of firms in the future. However, his specific suggestions are based on sparse evidence, and his alternative to the eclectic paradigm is founded on a misunderstanding of some fundamental concepts.