Ring Containing Polymers or Macromolecular Necklaces (Polyrotaxanes and Polycatenanes) – Roaming Toward Nanocomposites and Functional Applications

ABSTRACT Ring containing polymers, also termed as macromolecular necklaces, have opened myriad of new technical possibilities for advanced materials due to unique chained ring sequences in backbones. Commonly known ring containing polymers, like polyrotaxanes and polycatenanes are made up of mechanically interlocked monomeric molecules, rotaxanes and catenanes, respectively. These macromolecular sequences own intrinsically dynamic covalent/mechanical bonding, supramolecular chemistries, conformational related backbone mobility, flexibility, and structural integrity. Recently, increasing scientific interest seems trending toward design and exploration of blends and nanocomposites of polyrotaxanes and polycatenanes with nanocarbon (graphene, carbon nanotubes) and inorganic (metal, nanoclay, MOF, MXene) nanoparticles. Accordingly, this review is planned to highlight dynamics of macromolecular necklaces and derived materials, involving unique design varieties, fabrication, structural/microstructural specifications, conducting, mechanical, thermal, and other exceptional characteristics. Ultimately, high end applications of polyrotaxanes and polycatenanes based blends and nanocomposites have been discussed for phase change materials, electronics (sensors, actuators, batteries), scratch resistant coatings, and biomedical (drug delivery, tissue engineering, wound healing) applications. Despite scientific progress so far in the field of macromolecular necklaces, upcoming researchers must explore new design/fabrication possibilities and applied potential of polyrotaxanes/polycatenanes derived materials via understanding key role of ring structure/mobility in determining their physical and applied dynamics for commercial-scale manufacturing. GRAPHICAL ABSTRACT