Controlled synthesis and optical investigation of conjugated rod-coil diblock copolymer based on poly(3-hexylthiophene) and poly(2-(dimethylamino)ethyl methacrylate-random-1-pyrenylmethyl methacrylate-random-methacrylate spirooxazine)

This research presents a conjugated rod–coil diblock copolymer P3HT-b-P(DMAEMA-r-PyMA-r-MSp) which was synthesized by a combination of the Kumada catalyst-transfer polymerization and ATRP method of co-monomers including 2-(dimethylamino)ethyl methacrylate (DMAEMA), 1-pyrenylmethyl methacrylate (PyMA) and methacrylate spirooxazine (MSp). The synthesized copolymer P3HT-b-P(DMAEMA-r-PyMA-r-MSp) revealed a controlled molecular weight of 12,200 g/mol with a dispersity index of 1.16. The chemical structure of the diblock polymer was confirmed via ¹H NMR and FTIR spectroscopies. In addition, its optical and thermal properties were also investigated via differential scanning calorimetry (DSC), UV–Vis and photoluminescence spectroscopies. The influence of solvent polarity on the conformational states and optical properties of the regioregular P3HT chains was examined.

Graphical abstract

Multi-responsive conjugated rod-coil block copolymers have attracted due to their response to external signals, resulting in structure, shape, and property changes in the coil segments. This class of copolymers combines the tunable structural control and photophysical properties of conjugated rods with the self-assembly behavior and physical properties of block copolymers. The morphologies of block copolymers have been extensively researched, attracting fundamental and application-oriented interests. The diblock copolymers with hydrophilic and hydrophobic segments exhibit distinct natures that give rise to unique phase behaviors in nanometer dimensions, leading to a broad range of applications, including data recording, optical switching, drug delivery systems, and sensors. In this research, a rod-coil diblock copolymer P3HT-b-P(DMAEMA-r-PyMA-r-MSp) which was synthesized by a combination of the Kumada catalyst-transfer polymerization and ATRP polymerization of co-monomers including 2-(dimethylamino)ethyl methacrylate (DMAEMA), 1-pyrenylmethyl methacrylate (PyMA) and methacrylate spirooxazine (MSp). The synthesized diblock polymer P3HT-b-P(DMAEMA-r-PyMA-r-MSp) reveals a controlled molecular weight of 15200 g/mol with a dispersity index of 1.16. The chemical structure of the diblock copolymer was confirmed via 1H NMR and FTIR spectroscopies. In addition, its optical and thermal properties were also investigated through differential scanning calorimetry (DSC) and UV-Vis spectroscopies.