Tacticity-independent crystallization of polymers

Crystallization, a phase transition that is prevalent in nature, provides unique molecular arrangements that impact the structure-dependent properties of a material. Owing to thermodynamic and kinetic factors, synthetic polymeric materials show only partial ordering. Indeed, usually polymers that possess sufficient stereo- and regioregularity can partially crystallize. Atactic polymers that do not meet the minimum regularity in the chemical structure needed to pack chains within a crystal unit cell are completely amorphous. However, there are unusual cases where stereoirregular, atactic polymers can crystallize; this happens when the structural features of the atactic polymers provide specific ordering so that their irregular chains can pack into crystalline structures. This Review not only highlights the general relationship between the structures required in atactic polymers to induce crystallization but also provides researchers with the tools to design polymer systems with crystallinity without requiring exquisite stereocontrol in their synthesis.