Polymer Blending through Host-Guest Interactions

In this work, a supramolecular approach, based on molecular recognition, was used to direct the blending of immiscible polymers toward compatibility and even molecular miscibility. A slight modification of the two immiscible polymers polystyrene (PS) and poly(butyl methacrylate) (PBMA), with the introduction of the two recognition groups tetraphosphonate cavitand (HOST) and methylpyridinium (GUEST), respectively, led to the formation of compatible mixtures between them, characterized by a single T-g and by an homogeneous texture at the surface level, as evidenced by AFM measurements. The energetically favorable host-guest interactions among polymeric chains overcome their repulsive interfacial energy, leading to the suppression of phase segregation at the level of material. The complexation between PS-HOST and PBMA-GUEST copolymers has been demonstrated to be reversible by the action of a specific external stimulus in the form of guest exchange with the competitive N-methylbutyl ammonium chloride.