title: CdS quantum dots doped tuning of deswelling kinetics of thermoresponsive hydrogels based on poly(2-(2-methoxyethoxy)ethyl methacrylate).
abstract: Thermoresponsive poly(2-(2-methoxyethoxy)ethyl methacrylate) (PMEO2MA) based hybrid nanocomposite hydrogels (NCH) were synthesized by dispersing preformed cadmium sulfide (CdS) quantum dots (QDs) in the reaction mixture followed by polymerization via reversible addition-fragmentation chain transfer (RAFT) technique. High doping capacity and negligible QDs leakage were observed for hydrophilic QDs doped hydrogels (hpl-NCH) due to H-bonding interactions between QDs and pendant groups of hydrogel network. The hpl-NCH networks showed improved structural/orientational order and swelling ratios with increasing doping concentration compared to the organic hydrogel (OH). Opposite trends were observed for bulk-CdS (NCH-bulk) and 1-dodecanethiol capped CdS (NCH-DDT) doped hydrogels. Swelling induced linear retardance and quenching of photoluminescence (PL) intensity for hydrogels were exploited to study the deswelling kinetics respectively by Mueller matrix polarimetry and solid state fluorimetry, which were further corroborated with gravimetric analysis. For all the NCH, deswelling process significantly decreased with increasing temperature, which followed the order: 30 > 45 > 60 °C. Slower deswelling was observed for NCH-bulk and hpl-NCH compared to the OH, and also with increase in doping concentration due to the formation of skin layer. However, NCH-DDT exhibited accelerated deswelling process and the order was reversed with respect to doping concentration due to DDT mediated enhanced hydrophobic aggregation and water leakage channels created by long hydrophobic free-mobile nature of QDs surface tethered DDT molecules. The presented methodology provides tunable deswelling of PMEO2MA based hydrogels by doping with hydrophilically/hydrophobically modified CdS QDs.
authors.affiliation: Polymer Research Centre, Department of Chemical Sciences, Indian Institute of Science Education and Research , Kolkata, PO: BCKV Campus Main Office, Mohanpur 741252, Nadia, West Bengal, India.
authors.forename: Nagaraj
authors.initials: N
authors.lastname: Patil
authors.forename: Saswati Ghosh
authors.initials: SG
authors.lastname: Roy
authors.forename: Ujjal
authors.initials: U
authors.lastname: Haldar
authors.forename: Priyadarsi
authors.initials: P
authors.lastname: De
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D020100:Hydrogels; D007700:Kinetics; D008689:Methacrylates / Q000737:chemistry*; D008855:Microscopy, Electron, Scanning; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*
chemical_list: D019187:Cadmium Compounds; D020100:Hydrogels; D008689:Methacrylates; D018036:Selenium Compounds; C581192:poly(2-(2-methoxyethoxy)ethyl methacrylate); C058667:cadmium selenide