The thermoresponsive behaviour of a poly(N-isopropylacrylamide) hydrogel with a D-π-A type pyran-based fluorescent dye

Multi-responsive poly(N-isopropylacrylamide) hydrogel with D-π-A type dye

“…All employed solvents were analytically pure and were employed without any further drying or purification. Allyl 2-cyano-2-(2,6-dimethyl-4H-pyran-4-ylidene)acetate 1 and 4-(bis(pyridin-2-ylmethyl)amino)-benzaldehyde 2 were prepared by the literature procedure, respectively [18,38]. …”

“…In previous papers [18,19], we have reported thermo-responsive behavior and photoregulated optical switching in PNIPAM copolymers with D-p-A type fluorophore. The acid/base-induced optical switching of the D-p-A type dyes has also been reported [20][21][22][23][24].…”

Temperature-induced phase transition and intramolecular charge-transfer process based on poly(N-isopropylacrylamide) hydrogel with covalently attached D–π–A type dye

“…In previous papers [16,17], we have reported thermoresponsive behavior and photoregulated optical switching in PNIPAM copolymers with electron donor-p-conjugate-electron acceptor (D-p-A) type fluorophore. Also reported is the acid/base-induced optical switching of the D-p-A type dyes [18][19][20][21][22].…”

Thermo- and Acid/base-induced Spectral Switching of a Poly(N-isopropylacrylamide) Copolymer Containing Benzopyran-based D-π-A type Dye Units

“…The polymer is hydrophilic and soluble in water below the LCST, but becomes hydrophobic and forms a macroscopic coacervate phase above that temperature due to the fluctuation of hydrophobic interactions and hydrogen bonding 7) . In previous papers 8,9) , we have reported thermoresponsive behavior and photoregulated optical switching in PNIPAM copolymers with electron donor-π -conjugate-electron acceptor (D-π-A) type fluorophore. Also reported has been the acid/base-induced optical switching of the D-π-A type dyes [10][11][12][13][14] .…”

“…2-Methyl-chromene-4-one 1 was prepared by the literature procedure 16) . The compound 3, containing a polymerizable functional allyl group, was successfully obtained by condensing 2-methyl-chromene-4-one 1 and allyl cyanoacetate 2 in acetic anhydride solution refluxed for 24 h. D-π-A type dye monomer 5 was obtained by condensation reaction with compound 3 and indole-3-carboxaldehyde 4 using piperidine as catalyst 9) . In the next step, this dyefunctionalized monomer 5 was copolymerized with N-isopropylacrylamide 6 by conventional radical .…”