@article{guo_abdala_may_lincoln_khan_prud'homme_2006, title={Rheology control by modulating hydrophobic and inclusion associations in modified poly(acrylic acid) solutions}, volume={47}, ISSN={["1873-2291"]}, DOI={10.1016/j.polymer.2006.03.006}, abstractNote={The rheology of modified poly(acrylic acid) (PAA) solutions can be tuned by controlling the inclusion interactions between α-cyclodextrins and alkyl hydrophobes. We demonstrate three modes of control: (1) using free cyclodextrins (CD) to displace hydrophobe–hydrophobe association in hydrophobically modified poly(acrylic acid) (HMPAA) polymers—which reduces fluid viscosity, (2) using competitive inclusion interactions where stronger SDS:CD binding can be used to ‘unmask’ CD:hydropobe inclusion interactions—which increases viscosity, and (3) employing HMPAA inclusion interactions with CD groups grafted to PAA chains (CDPAA)—which produces higher viscosities than purely hydrophobic association systems at the same concentration. The inclusion association between alkyl side-group in HMPAA and CD, either free or grafted onto PAA, obeys a 1-to-1 stoichiometry at low polymer concentrations (<1 wt%). In contrast to purely hydrophobically associating polymers, the CD:hydrophobe interaction is only binary, and, therefore, these associated networks should be ideal model systems to test theoretical predictions for associative fluids.}, number={9}, journal={POLYMER}, author={Guo, Xuhong and Abdala, Ahmed A. and May, Bruce L. and Lincoln, Stephen F. and Khan, Saad A. and Prud'homme, Robert K.}, year={2006}, month={Apr}, pages={2976–2983} }
 @article{guo_abdala_may_lincoln_khan_prud'homme_2005, title={Novel associative polymer networks based on cyclodextrin inclusion compounds}, volume={38}, ISSN={["1520-5835"]}, DOI={10.1021/ma050071o}, abstractNote={ADVERTISEMENT RETURN TO ISSUEPREVNoteNovel Associative Polymer Networks Based on Cyclodextrin Inclusion CompoundsXuhong Guo, Ahmed A. Abdala, Bruce L. May, Stephen F. Lincoln, Saad A. Khan, and Robert K. Prud'hommeView Author Information Department of Chemical Engineering, Princeton University, Princeton, New Jersey 08544; Departmant of Chemistry, University of Adelaide, Adelaide, SA 5005, Australia; and Department of Chemical Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905 Cite this: Macromolecules 2005, 38, 7, 3037–3040Publication Date (Web):March 8, 2005Publication History Received12 January 2005Published online8 March 2005Published inissue 1 April 2005https://doi.org/10.1021/ma050071oCopyright © 2005 American Chemical SocietyRIGHTS & PERMISSIONSArticle Views1678Altmetric-Citations81LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InReddit Read OnlinePDF (154 KB) Get e-AlertsSUBJECTS:Hydrophobicity,Macrocyclic compounds,Oligosaccharides,Polymers,Viscosity Get e-Alerts}, number={7}, journal={MACROMOLECULES}, author={Guo, XH and Abdala, AA and May, BL and Lincoln, SF and Khan, SA and Prud'homme, RK}, year={2005}, month={Apr}, pages={3037–3040} }
 @article{zanten_amin_abdala_2004, title={Brownian motion of colloidal spheres in aqueous PEO solutions}, volume={37}, ISSN={["1520-5835"]}, DOI={10.1021/ma035250p}, abstractNote={The Brownian motion of colloidal spheres in aqueous poly(ethylene oxide) (PEO) solutions ranging in concentration from 0.2 to 15 wt % is measured with diffusing wave spectroscopy over more than 6 decades of time. The measured colloidal sphere mean-squared displacements are shown to satisfy the generalized Stokes−Einstein relation that relates the particle mean-squared displacement to the polymer solution shear modulus as the microrheological creep compliance calculated from the colloidal sphere Brownian motion was found to agree with that measured by mechanical rheometry. The microrheological zero shear viscosity concentration dependence for the entangled solution regime, η ∼ c4.7, is in agreement with that reported by others from mechanical rheometry measurements on polymer−good solvent solutions and is stronger than the tube model prediction, η ∼ c3.9. Essentially the entire deviation between the predicted and measured entangled solution regime zero shear viscosity concentration dependence is accounted ...}, number={10}, journal={MACROMOLECULES}, author={Zanten, JH and Amin, S and Abdala, AA}, year={2004}, month={May}, pages={3874–3880} }
 @article{abdala_wu_olesen_jenkins_khan_tonelli_2004, title={Solution rheology of hydrophobically modified associative polymers: Effects of backbone composition and hydrophobe concentration}, volume={48}, ISSN={["1520-8516"]}, DOI={10.1122/1.1773781}, abstractNote={We investigate the effects of polymer molecular structure on the solution rheology of a hydrophobically modified associative polymer comprised of macromonomers with alkyl hydrophobes attached to a poly(ethyl acrylate-co-methacrylic acid) backbone. In particular, the effect of polymer backbone composition with variable proportions of methacrylic acid (MAA) and ethyl acrylate (EA) are examined. We find that the concentration of the MAA monomer has a large impact on polymer viscoelasticity. Polymers with low MAA content have smaller hydrodynamic size that result in lower viscosities and dynamic elastic moduli compared to polymers with high MAA content. Moreover, the balance between the polymer hydrodynamic size, the chain flexibility, and the aggregation of the EA blocks yield maxima in these material functions with respect to the MAA concentration. The scaling of shear viscosity, high frequency elastic modulus, and creep compliance with polymer concentration exhibits power-law behavior with different exponents. In all cases, three power-law regimes, regardless of the MAA content, are observed that can be attributed to the presence of different modes of hydrophobic interaction. However, the transitions shift to lower concentrations as the MAA content increases. With regards to the effects of the macromonomer side-chain concentration, we observe a substantial increase in viscosity at intermediate macromonomer content (1 mol %), possibly due to an increase in the number of intermolecular junctions as the number of hydrophobes per chain increases. This is in contrast to (i) low macromonomer concentration (0.3 mol %) behavior that reveals low viscosity due to weak hydrophobic associations, and (ii) high macromonomer concentration (1.9 mol %) behavior that favors more intramolecular association resulting in lower viscoelastic properties compared to intermediate macromonomer concentrations.We investigate the effects of polymer molecular structure on the solution rheology of a hydrophobically modified associative polymer comprised of macromonomers with alkyl hydrophobes attached to a poly(ethyl acrylate-co-methacrylic acid) backbone. In particular, the effect of polymer backbone composition with variable proportions of methacrylic acid (MAA) and ethyl acrylate (EA) are examined. We find that the concentration of the MAA monomer has a large impact on polymer viscoelasticity. Polymers with low MAA content have smaller hydrodynamic size that result in lower viscosities and dynamic elastic moduli compared to polymers with high MAA content. Moreover, the balance between the polymer hydrodynamic size, the chain flexibility, and the aggregation of the EA blocks yield maxima in these material functions with respect to the MAA concentration. The scaling of shear viscosity, high frequency elastic modulus, and creep compliance with polymer concentration exhibits power-law behavior with different expone...}, number={5}, journal={JOURNAL OF RHEOLOGY}, author={Abdala, A. A. and Wu, W. J. and Olesen, K. R. and Jenkins, R. D. and Khan, Saad and Tonelli, A. E.}, year={2004}, pages={979–994} }
 @article{abdala_tonelli_khan_2003, title={Modulation of hydrophobic interactions in associative polymers using inclusion compounds and surfactants}, volume={36}, ISSN={["1520-5835"]}, DOI={10.1021/ma034173v}, abstractNote={We report the modulation of the solution rheology of a comblike, hydrobhobically modified alkali-soluble emulsion (HASE) associative polymer through addition of α- and β-cyclodextrins (CDs). The ring-shaped CDs with hydrophobic inner cores interact with the pendant macromonomer segments of the associative polymer containing hydrophobic end groups, leading to reduction in polymer solution viscosity and dynamic moduli by several orders of magnitude. We find no interactions between the CDs and the polymer backbone as substantiated by the fact that an analogous parent polymer without hydrophobes reveals no changes in the solution rheology in the presence of CDs. In contrast, the CDs encapsulate the hydrophobic groups on the associative polymer. This is confirmed by the complexation between the CD and a surfactant modified to resemble the hydrophobic macromonomer of the associative polymer as observed using 1H NMR, differential scanning calorimetry (DSC), and thermal gravimetric analysis (TGA). The stoichiomet...}, number={20}, journal={MACROMOLECULES}, author={Abdala, AA and Tonelli, AE and Khan, SA}, year={2003}, month={Oct}, pages={7833–7841} }
 @article{abdala_olesen_khan_2003, title={Solution rheology of hydrophobically modified associative polymers: Solvent quality and hydrophobic interactions}, volume={47}, number={2}, journal={Journal of Rheology (New York, N.Y.)}, author={Abdala, A. A. and Olesen, K. and Khan, S. A.}, year={2003}, month={Mar}, pages={497–511} }
 @article{mahammad_abdala_roberts_khan, title={Manipulation of hydrophobic interactions in associative polymers using cyclodextrin and enzyme}, volume={6}, number={17}, journal={Soft Matter}, author={Mahammad, S. and Abdala, A. and Roberts, G. W. and Khan, S. A.}, pages={4237–4245} }