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Interactions and Dynamics in Aqueous Solutions of pH-Responsive Polymers: A Combined Fluorescence and Dielectric Relaxation Study.
Kumbhakar, Kajal; Dey, Asmita; Mondal, Amrita; De, Priyadarsi; Biswas, Ranjit.
Afiliación
  • Kumbhakar K; Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India.
  • Dey A; Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246 Nadia, West Bengal, India.
  • Mondal A; Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India.
  • De P; Polymer Research Centre and Centre for Advanced Functional Materials, Department of Chemical Sciences, Indian Institute of Science Education and Research Kolkata, Mohanpur, 741246 Nadia, West Bengal, India.
  • Biswas R; Chemical, Biological and Macromolecular Sciences (CBMS), S. N. Bose National Centre for Basic Sciences, JD Block, Sector III, Salt Lake, Kolkata 700106, India.
J Phys Chem B ; 125(22): 6023-6035, 2021 06 10.
Article en En | MEDLINE | ID: mdl-34057364
Interaction and dynamics of aqueous solutions of pH-responsive smart polymers are investigated via steady-state, time-resolved fluorescence emission spectroscopy with the help of external local reporter coumarin 153 (C153), while MHz to GHz dielectric relaxation spectroscopic (DRS) measurement reports the intrinsic medium relaxation features. A series of pH-responsive random copolymers (DPL-DP60) comprising of a pH-responsive moiety 2-((leucinyl)oxy)ethyl methacrylate (l-Leu-HEMA) and hydrophobic methyl methacrylate (MMA) are synthesized and characterized. A balance between the pH-responsive (l-Leu-HEMA) and the hydrophobic (MMA) content dictates the phase transition pH, which is found to be ∼5-7 for these aqueous copolymer solutions (1 mg/mL). Dynamic light scattering measurements in aqueous solutions of these polymers reflect a small particle size (∼2-8 nm) at solution pH below their individual phase transition pH, while a large particle size (∼140-340 nm) forms beyond their phase transition pH. No signature of a phase transition pH-driven abrupt change in static and dynamic properties of aqueous polymer solutions has been registered from pH-dependent dielectric relaxation as well as solute (C153)-centric fluorescence measurements. A significant impact of varying the l-Leu-HEMA/MMA segment ratio on steady-state fluorescence emission and rotational anisotropy decay of the fluorophore solute (C153) has been observed. MHz to GHz DRS in aqueous solutions of these pH-responsive polymers reflects bulk water-like dielectric features.
Asunto(s)

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Polímeros / Metacrilatos Idioma: En Revista: J Phys Chem B Asunto de la revista: QUIMICA Año: 2021 Tipo del documento: Article País de afiliación: India

Texto completo: 1 Colección: 01-internacional Banco de datos: MEDLINE Asunto principal: Polímeros / Metacrilatos Idioma: En Revista: J Phys Chem B Asunto de la revista: QUIMICA Año: 2021 Tipo del documento: Article País de afiliación: India