01877nas a2200145   4500008004100000245015800041210006900199260000800268300001400276490000700290520125800297100002001555700002601575856013001601       2017                        eng d00aSynthesis and tunable thermoresponsive solution morphologies of 2,2-bis-methylolpropionic acid dendron-azobenzene-poly(N-isopropyl acrylamide) copolymers0 aSynthesis and tunable thermoresponsive solution morphologies of   cJUL  a1084-10930 v663 aAmphiphilic temperature- and photoresponsive linear-dendritic block copolymers comprising second-generation acetonide-2,2-bis-methylolpropionic acid-based polyester dendron and linear poly(N-isopropyl acrylamide) (PNIPAM) linked by an azobenzene unit were synthesized using atom transfer radical polymerization (ATRP) followed by click chemistry. Linear PNIPAM precursor was prepared from an azide-functionalized azobenzene containing ATRP initiator. Two polymers obtained by varying the chain length of the PNIPAM block showed different morphologies and lower critical solution temperature (LCST) values in aqueous solution. Complete change in morphology of the two polymers into large spherical aggregates and nanotubes, respectively, was observed upon heating the micellar solution above LCST. The azobenzene unit was found to undergo trans-cis photoisomerization in the assemblies and caused a change in the microenvironment of an encapsulated hydrophobic dye without any release. Acetonide groups on the dendron were deprotected to afford hydroxylated polymer that showed well-defined morphologies above the LCST and after heating-cooling cycle while significant dye encapsulation was seen only above the LCST. (c) 2017 Society of Chemical Industry1 aKalva, Nagendra1 aAmbade, Ashootosh, V.  uhttps://library.ncl.res.in/content/synthesis-and-tunable-thermoresponsive-solution-morphologies-22-bis-methylolpropionic-acid