Polymeric materials macroscopic scale changes

Figure 1. If there is a connection between the molecular, macromolecular and macroscopic scale changes in polymeric materials, then macromolecular and macroscopic scale changes can be predicted from the molecular scale events.

Abiotic forces will not be in the focus of the discussion, but it is obvious that a polymeric material like PVAc or PVA exposed to outdoor conditions will undergo different alterations at the macroscopic and microscopic scales. Depending on its interaction with mechanical forces, thermal stress, radiation or chemical attack, the polymer properties might be changed in a way that is relevant for its interaction with biological systems. 

Another remarkable feature of responsive polymeric systems is that interactions on the molecular scale (the stimulus of some sort) lead to macroscopically detectable changes that are finally employed for the function (e.g., directed delivery of drugs). As the molecular-scale interactions and macroscopic function are so intimately linked it is noteworthy that rather few studies have dealt with the nanoscopic level of these materials. This may be due to the fact that many conventional methods of physical polymer characterization may simply not be able to resolve the many different, often counteracting interactions [18, 49, 50]. In processes like a response of any kind, solvent-polymer, solvent-solvent, and polymer-polymer interactions all play a cmcial role. Better understanding of the structure and interactions on the nanoscale is not only of value in itself but it may also shed light on similar processes in biomacromolecules and may aid the design and control of responsive polymers with respect to their applications [8, 48, 49]. These applications can be counted to the above-mentioned societal need of health, as responsive polymers are hot candidates for, e.g., drug or nucleic acid delivery purposes. 

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