Extended molecular systems, component relations

One may however consider that the integrated operation of its individual components confers to a molecular (covalently linked) device a flavour of supramolecular nature, since its function extends over the whole device in a sort of superstructure fashion. It then would appear justified to include in the domain of supramolecular chemistry systems that bear relation to supramolecular species on functional grounds, systems whose function is of supramolecular nature although they are clearly molecular in terms of structure and bonding. A further reason for not excluding such a possibility lies in the considerable enrichment that such an open view brings to the field ... 

So far most of the pertinent literature interprets interactions between polymer and a second sorbed component on the basis of the colligative properties of the system. This information is summarized in Sect. 2 of this review. From those reports, I inferred that some sort of association of the small penetrant molecules with the repeat unit of the polymer is a prerequisite condition for the sequential changes described above. This implies that the magnitude of polymer swelling should be directly related to how well the molecular structure of the small molecule can be accommodated by the molecular structure of the polymer repeat unit in view of the macrostructure of that polymer (i.e. the crosslink density). The results obtained in our laboratory, which are summarized in Sect. 3 of this Review, are thoroughly consistent with that hypothesis. In Sect. 4 these interpretations are extended to correlate the colligative properties of Sect. 2. 

The modelling of complex systems like this can be approached using several methods. Froment and co-workers [3,4] use a molecular approach, relating the activity of substituted compounds to the activity of the non-substituted ring-stracture. This gives good results, but the model is complex and involves extended analytical work to identify the components. 

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