Uniform two-dimensional square assemblies from conjugated block copolymers driven by \u03c0\u2013\u03c0 interactions with controllable sizes

Liang Han,Hujun Qian,Xiangmeng Jia,Feng He,Wei Chen,Meijing Wang

doi:10.1038/s41467-018-03195-y

Abstract

Two-dimensional (2-D) micro- and nano-architectures are attractive because of their unique properties. However, the formation of 2-D supramolecular highly symmetrical structures with considerable control is still a major challenge. Here we present a simple approach for the preparation of regular and homogeneous 2-D fluorescent square non-crystallization micelles with conjugated diblock copolymers PPV12-b-P2VPn through a process of dissolving–cooling–aging. The scale of the formed micelles can be controlled by the ratio of PPV/P2VP blocks and the concentration of the solution. The results reveal that the micelles of PPV12-b-P2VPn initially form 1-D structures and then grow into 2-D structures in solution, and the growth is driven by intermolecular π–π interactions with the PPV12 blocks. The formation of 2-D square micelles is induced by herringbone arrangement of the molecules, which is closely related to the presence of the branched alkyl chains attached to conjugated PPV12 cores.

Highlights

Two-dimensional (2-D) micro- and nano-architectures are attractive because of their unique properties
The PPValdehyde homopolymer was prepared by Siegrist polycondensation and the monomer number of PPV block was calculated to be 12 by nuclear magnetic resonance (NMR), whose polydispersity was 1.05 determined by gel permeation chromatography (GPC)
The solution was heated at 85 °C for 45 min, it was slowly cooled to room temperature (25 °C) followed by aging for 24 h

Summary

Introduction

Two-dimensional (2-D) micro- and nano-architectures are attractive because of their unique properties. As the creation of synthetic 2-D materials represents an attractive challenge that is driven by their prospective uses in, e.g., electronics, biomedicine, catalysis, sensing, and as membranes for separation and filtration[1], the acquisition of uniform 2-D assemblies with regular shapes has more important significance Achieving such a uniform architecture through non-crystallization-derived approaches[10] such as Van der Waals’ forces, hydrophilic/hydrophobic interactions, hydrogen bonds, and π–π interactions is challenging and fascinating. We combine PPV blocks and poly (2-vinyl pyridine) (P2VP) to build amphiphilic diblock copolymers PPV12-bP2VPn with sheet–coil-type structures, and colloidally stable 2-D fluorescent square micelles are formed in certain solvents, such as isopropanol, with easy approaches. In view of the perfect optical and electronic properties of PPV blocks, the forming square micelles should have potential applications in the fields of organic field effect transistors (OFET), organic photovoltaic (OPV), and biosensing

Methods

Results

Conclusion