@article { ISI:000232218700049,
	title = {Thermoreversible behavior of associating polymer solutions: thermothinning versus thermothickening},
	journal = {Macromolecules},
	volume = {38},
	number = {20},
	year = {2005},
	month = {OCT},
	pages = {8512-8521},
	publisher = {AMER CHEMICAL SOC},
	type = {Article},
	address = {1155 16TH ST, NW, WASHINGTON, DC 20036 USA},
	abstract = {<p>Self-assembling properties of poly(sodium acrylate) grafted with dodecyl [C12], PAAgC12, or poly(N-isopropylacrylamide) [PNIPA] side chains, PAAgPNIPA, were studied in unentangled semidilute aqueous solution. While PAAgC12 self-associates through hydrophobic interactions, the gelation of PAAgPNIPA is triggered by heating in response to the lower critical solution temperature of PNIPA (LCST similar to 32 degrees C). The local structure of the physical networks was investigated by small-angle neutron scattering, and the scattering patterns were described using a polydisperse sphere model taking into account hard-sphere interactions. This model allow us to draw a realistic picture of physical gels with quantitative information concerning the size of hydrophobic cores, the volume fraction of stickers in the aggregates, the fraction of stickers which take part in the aggregation process, the range of repulsive interactions, and the structural modifications induced by temperature. The description of the network is in good agreement with complementary data obtained from DSC and C-13 NMR. In the present work, a special emphasis has been given to the important relationship existing between the viscoelastic properties of associating polymer solutions and the binding energy of stickers leaving temporarily the micellar junction. Depending on the endothermic or exothermic nature of the disengagement process of the sticker (heat of demicellization), the relaxation time of the network and the viscoelastic properties will either decrease or increase with the temperature. The consequence is that aqueous solutions of PAAgC12 and PAAgPNIPA exhibit opposite rheological properties with the temperature, namely thermothinning and thermothickening. By mixing these two copolymers, we show that intermediate properties can be obtained but in that case a microphase-separated network is obtained as a result of copolymer segregation.</p>},
	issn = {0024-9297},
	doi = {10.1021/ma050786r},
	author = {Hourdet, Dominique and Gadgil, Jayant and Podhajecka, K. and Badiger, Manohar V. and Brulet, A. and Wadgaonkar, P. P.}
}
@article { ISI:000318748300011,
	title = {Thermodynamic behavior of hydrophobically modified polyacrylamide containing random distribution of hydrophobes: experimental and theoretical investigations},
	journal = {Polymer},
	volume = {54},
	number = {11},
	year = {2013},
	month = {MAY},
	pages = {2676-2689},
	publisher = {ELSEVIER SCI LTD},
	address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, OXON, ENGLAND},
	abstract = {<p>Two series of Hydrophobically Modified Polyacrylamides (HMPAMs) were prepared by free radical copolymerization of trimethylsilylacrylamide with 3-pentadecylcyclohexylacrylamide (PDCAM) or dodecylacrylamide (DDAM) followed by removal of trimethylsilyl protecting groups. The solution properties of HMPAMs were studied in dilute aqueous solution by fluorescence spectroscopy, NMR and viscometry. The properties in aqueous solution of HMPAMs clearly displayed the formation of hydrophobic interactions between alkyl stickers. While dodecyl containing HMPAMs mainly showed a progressive collapse of the copolymer coil with the increasing fraction of hydrophobic moieties (weak intra-chain associations), pentadecylcyclohexyl groups containing HMPAMs exhibited a much lower solubility in water due to strong intra- and inter-chain associations. Experimental data were analyzed using the mean field theory developed by Semenov and Rubinstein (SR) for associating polymers. Using a set of realistic parameters, taking into account the solubility of the backbone, the fraction of stickers and the strength of hydrophobic attractions, we show that the SR model offers a quantitative description of the thermodynamic properties of HMPAMs in terms of individual and collective behavior of polymers chains; i.e. swelling and phase separation, respectively. (C) 2013 Elsevier Ltd. All rights reserved.</p>},
	keywords = {Associating polymer, Polyacrylamide, Self-assembling},
	issn = {0032-3861},
	doi = {10.1016/j.polymer.2013.03.039},
	author = {Hourdet, Dominique and Ducouret, Guylaine and Varghese, Sony and Badiger, Manohar V. and Wadgaonkar, Prakash P.}
}
