Fabrication of 2D surface-functional polymer platelets via crystallization-driven self-assembly of poly(epsilon-caprolactone)-contained block copolymers

摘要

Fabrication of self-supported 2D organic materials with controllable surface properties is a challenge due to their thermodynamic instability. Herein, a series of crystalline-coil block copolymers poly(epsilon-caprolactone)-b-poly (acrylic acid) (PCL-b-PAA) with different compositions were synthesized for this purpose by the ring opening polymerization (ROP) of epsilon-aprolactone (epsilon-CL) and the subsequent atom transfer radical polymerization (ATRP) of tert-butyl acrylate, followed by treatment of trifluoroacetic acid (TFA). Two 2D polymer platelets with the spindle shape and the elongated truncated lozenge-like shape, respectively, were successfully fabricated via crystallization-driven self-assembly of the as-synthesized PCL-b-PAA. Effect of the properties of solvents and block copolymer compositions on the morphologies of 2D polymer platelets were carefully studied. The resultant 2D polymer platelets can quickly respond to environmental pH values due to the PAA chains tethered on surface of PCL crystals can undergo a different degree of ionization as pH changes. Moreover, Ag nanoparticles were also successfully loaded on the 2D polymer platelets by in situ reduction of AgNO3.