Polymer mechanochemistry: Techniques to generate molecular force via elongational flows

Long chain polymers have a unique ability to become highly extended in elongational flow fields. The forces developed along the backbone give rise to scission of the chains near their center. Recently, this unique property of polymers has been adopted to explore new chemical transformations by embedding structural elements into the backbone designed to undergo site-specific bond cleavage, termed mechanophores. Experimental techniques to generate elongational flow fields exist in a variety of different arrangements and have been used to study polymer mechanochemistry in solution. This tutorial review will discuss progress in the field of polymer mechanochemistry as well as survey the techniques used to generate elongational flow fields. Ultrasonication will be highlighted as the technique that has been widely adopted to screen mechanophore reactivity in solution.