Self‐Templating Copolymerization to Produce Robust Conductive Nanocoatings Based on Conjugated Polymer Brushes with Implementable Memristive Characteristics

Abstract

An effective synthesis of conductive polymer brushes, i.e., self‐templating surface‐initiated copolymerization (ST‐SICP), is developed. It proceeds through copolymerization of pendant thiophene groups in the precursor multimonomer poly(3‐methylthienyl methacrylate) (PMTM) brushes with free 3‐methylthiophene (3MT) monomers leading to PMTM‐co‐P3MT brushes. This approach leads to improved conformational freedom of generated conjugated poly(thiophene)‐based chains and their higher share in the brushes with respect to conjugation of pendant thiophene groups only. As a result, best performing conjugated PMTM‐co‐P3MT brushes demonstrate high ohmic conductivity in both out‐of‐plane and in‐plane direction. Furthermore, thanks to the covalent anchoring as well as intra‐ and intermolecular connections, highly stable and mechanically robust nanocoatings are produced which can survive mechanical cleaning and long‐term storage under ambient conditions. Grafting of ionic poly(sodium 4‐styrenesulfonate) (PSSNa) in between PMTM‐co‐P3MT chains brings new properties to such binary mixed brushes that can operate as thin‐film memristive coating with switchable conductance. It is worth mentioning that the crucial synthetic steps, i.e., grafting of precursor PMTM brushes by surface‐initiated organocatalyzed atom transfer radical polymerization (SI‐O‐ATRP) and PSSNa chains by surface‐initiated photoiniferter‐mediated polymerization (SI‐PIMP) are conducted under ambient conditions using only microliter volumes of reagents providing methodology that can be considered for use beyond the laboratory scale.