Visualizing phase transition behavior of dilute stimuli responsive polymer solutions via Mueller matrix polarimetry.
Probing volume phase transition behavior of superdiluted polymer solutions both micro- and macroscopically still persists as an outstanding challenge. In this regard, we have explored 4 × 4 spectral Mueller matrix measurement and its inverse analysis for excavating the microarchitectural facts about stimuli responsiveness of "smart" polymers. Phase separation behavior of thermoresponsive poly(N-isopropylacrylamide) (PNIPAM) and pH responsive poly(N,N-(dimethylamino)ethyl methacrylate) (PDMAEMA) and their copolymers were analyzed in terms of Mueller matrix derived polarization parameters, namely, depolarization (Δ), diattenuation (d), and linear retardance (δ). The Δ, d, and δ parameters provided useful information on both macro- and microstructural alterations during the phase separation. Additionally, the two step action ((i) breakage of polymer-water hydrogen bonding and (ii) polymer-polymer aggregation) at the molecular microenvironment during the cloud point generation was successfully probed via these parameters. It is demonstrated that, in comparison to the present techniques available for assessing the hydrophobic-hydrophilic switch over of simple stimuli-responsive polymers, Mueller matrix polarimetry offers an important advantage requiring a few hundred times dilute polymer solution (0.01 mg/mL, 1.1-1.4 μM) at a low-volume format.
Polymer Research Centre, Department of Chemical Sciences, ‡Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata , Mohanpur 741246, Nadia, West Bengal, India.
Amal
A
Narayanan
Polymer Research Centre, Department of Chemical Sciences, ‡Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata , Mohanpur 741246, Nadia, West Bengal, India.
Shubham
S
Chandel
Polymer Research Centre, Department of Chemical Sciences, ‡Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata , Mohanpur 741246, Nadia, West Bengal, India.
Nirmalya
N
Ghosh
Polymer Research Centre, Department of Chemical Sciences, ‡Department of Physical Sciences, Indian Institute of Science Education and Research Kolkata , Mohanpur 741246, Nadia, West Bengal, India.
Priyadarsi
P
De
D000180:Acrylic Resins / Q000737:chemistry*; D008689:Methacrylates / Q000737:chemistry*; D009757:Nylons / Q000737:chemistry*; D055096:Optical Devices; D044367:Phase Transition; D012996:Solutions; D013696:Temperature
D000180:Acrylic Resins; D008689:Methacrylates; D009757:Nylons; D012996:Solutions; C407037:poly(2-(dimethylamino)ethyl methacrylate); C052970:poly-N-isopropylacrylamide