Regioregels

Regioregels are a class of polymeric gels whose network structure and properties are influenced by the regiochemical arrangement of functional groups along the polymer backbone. The term reflects the idea that the distribution of linkage patterns and crosslinkable motifs, such as head-to-tail versus head-to-head connections, can bias how the gel forms and how it behaves on a macroscopic level. Regioregularity can arise from the choice of monomers, the type of polymerization, or post-polymerization functionalization steps that create sites for crosslinking in a controlled, directional manner.

Synthesis and design strategies for regioregels include using monomers with defined regioselectivity in their bonding modes, employing living or controlled polymerization to bias sequence, and applying selective post-polymerization modifications to install crosslinkable groups at specific positions. These approaches aim to produce gels with anisotropic networks, where stiffness, porosity, or swelling differ along preferred directions.

Properties of regioregels are governed by the degree and pattern of regioregularity, affecting mechanical strength, swelling behavior, diffusive transport, and optical or electronic properties if conjugated segments are present. Such gels can exhibit enhanced actuation, directional diffusion, or tailored degradation.

Applications span biomedicine, including drug delivery and tissue engineering scaffolds, as well as sensors and soft actuators. Characterization typically involves nuclear magnetic resonance to quantify regioregularity, rheology to measure mechanics, swelling studies, and microscopy to assess network morphology. Regioregels remain an area of active research with ongoing efforts to map structure–property relationships and optimize processing.