Controlled Polymer Orientation via Metal-Organic Framework Nanomolding

The orientation of polymer chains plays a critical role in determining the properties and performance of polymeric materials. In this study, we developed a template-based approach to reorganize polymer assembly structures by aligning polymer chains in multiple directions within nanoporous metal-organic frameworks (MOFs). By using MOFs with one- and three-dimensional pore structures, we achieved the "nanomolding" of polyethylene terephthalate (PET) within the MOF pores. This technique allows us to manipulate the polymer chains at the molecular scale and achieve not only uniaxial alignment but also previously unachievable triaxial alignment of the polymer chains. Notably, this arrangement is preserved even after removal of the host MOFs. The thermal and crystallization properties of triaxially aligned PET differ significantly from those of PET having conventional random and uniaxial orientations. This MOF-based nanomolding approach offers new possibilities for controlling polymer alignments and has potential applications in the development of high-performance polymeric materials.