Abstract:

Associative thickeners are typically fabricated as a hydrophilic polymer framed by two hydrophobic end groups ("stickers") [1, 2]. To confer new properties to such systems [3], we explore amphiphilic block copolymers that contain one permanent hydrophobic sticker and one thermo-responsive "switchable" one. Beyond a specific temperature, this design results either in the formation of micellar networks via bridging, or of flower-like micelles via back-folding. In addition, we functionalize the polymers with a napthalimide dye on the permanent hydrophobic sticker end, and a coumarin dye at the opposite chain end. This fluorophore pair undergoes efficient Förster resonance energy transfer (FRET), enabling the investigation of back-folding during the thermally induced coil-to-globule phase transition of the polymers [4].Associative thickeners are typically fabricated as a hydrophilic polymer framed by two hydrophobic end groups ("stickers") [1, 2]. To confer new properties to such systems [3], we explore amphiphilic block copolymers that contain one permanent hydrophobic sticker and one thermo-responsive "switchable" one. Beyond a specific temperature, this design results either in the formation of micellar networks via bridging, or of flower-like micelles via back-folding. In addition, we functionalize the polymers with a napthalimide dye on the permanent hydrophobic sticker end, and a coumarin dye at the opposite chain end. This fluorophore pair undergoes efficient Förster resonance energy transfer (FRET), enabling the investigation of back-folding during the thermally induced coil-to-globule phase transition of the polymers [4].