Water-soluble conjugated polymers (WSCPs) have been widely used in chemical and biological sensing owning to their intriguing optoelectronic and biocompatible properties. However, these linear WSCPs suffer from the general drawbacks of low water-solubility and fluorescence quantum efficiency. Polymer brushes is a kind of unique macromolecules with a linear polymeric backbone and densely grafted side chains. Developing water-soluble conjugated polymer brushes (WSCPBs) is highly anticipated to solve the above mentioned problems. This article reviews the synthetic protocol and structure-properties relationship of WSCPBs to guide the design and preparation of new WSCPBs. In addition, we highlight the applications of WSCPBs in terms of sensor, bioimaging, drug delivery and surfactant. Finally, the future opportunities and challenges of WSCPBs are discussed.

Contents
1 Introduction
2 The synthesis of water-soluble conjugated polymer brushes
2.1 Grafting from approach
2.2 Grafting onto approach
2.3 Grafting through approach
3 Structure-properties relationship of water-soluble conjugated polymer brushes
3.1 Effects of conjugated backbone
3.2 Effects of graft side chains
4 Application of water-soluble conjugated polymer brushes
4.1 Sensor
4.2 Bioimaging
4.3 Drug delivery
4.4 Surfactant
5 Conclusion and outlook