One-Step/One-Pot Crystallization-Driven Co-Self-Assembly Strategy toward Controlled Preparation of π-Conjugated-Polymer-Containing Three-Dimensional Nanostructures

Abstract

Three-dimensional (3-D) π-conjugated-polymer-containing nanostructures of well-controlled composition/dimension exhibit promising applications in fields from nanomedicine to microelectronics. However, it remains a great challenge to easily and efficiently prepare hierarchical 3-D nanostructures in a controlled manner. In this work, we develop a one-step/one-pot strategy to generate flower-like nanostructures containing a core and numerous uniform nanofibers protruding from the central core by crystallization-driven co-self-assembly of OPE 9 - b -P2VP 56 [OPE = oligo( p -phenylene ethynylene); P2VP = poly(2-vinylpyridine); subscript represents the degree of polymerization] and poly(styrene sulfonic acid) (PSS) with a direct heating–cooling protocol. It is disclosed that the hydrogen bonding interactions between pyridyls of P2VP and −SO 3 H units of PSS not only accelerated the aggregation of OPE 9 - b -P2VP 56 unimers but also led to intermicellar aggregation of initially formed micelles driven by the solvophobic effect of complexes of P2VP/PSS domains upon cooling. Subsequently, unimers continued to deposit from exposed ends of nanofibers to give flower-like nanostructures. By variation of the content of OPE 9 - b -P2VP 56 and mass ratio of PSS to OPE 9 - b -P2VP 56, the length and number of nanofibers protruding from the core can be regulated. More importantly, the ends of protruding nanofibers remained active toward unimer deposition for further micellar elongation to afford flower-like nanostructures with segmented diblock nanofibers. In addition, the surface of protruding nanofibers can be further coated with Ag nanoparticles to give hybrid nanostructures by taking advantage of the coordinating capacity of pyridyls of P2VP chains. Given the excellent applicability of CDSA on diverse π-conjugated polymers, this work opens a new avenue to create diverse π-conjugated-polymer-based 3-D nanostructures in a controlled way.

Topics & Concepts