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Supramolecular Association of Hydrogen-Bonded Polybutadienes Functionalized with Ureidopyrimidone

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Supramolecular Association of Hydrogen-Bonded Polybutadienes Functionalized with Ureidopyrimidone University of Tennessee, Knoxville TRACE: Tennessee Research and Creative Exchange Doctoral Dissertations Graduate School 12-2014 Supramolecular Association of Hydrogen-bonded Polybutadienes Functionalized with Ureidopyrimidone Sachin Laxman Bobade University of Tennessee - Knoxville, [email protected] Follow this and additional works at: https://trace.tennessee.edu/utk_graddiss Recommended Citation Bobade, Sachin Laxman, "Supramolecular Association of Hydrogen-bonded Polybutadienes Functionalized with Ureidopyrimidone. " PhD diss., University of Tennessee, 2014. https://trace.tennessee.edu/utk_graddiss/3187 This Dissertation is brought to you for free and open access by the Graduate School at TRACE: Tennessee Research and Creative Exchange. It has been accepted for inclusion in Doctoral Dissertations by an authorized administrator of TRACE: Tennessee Research and Creative Exchange. For more information, please contact [email protected]. To the Graduate Council: I am submitting herewith a dissertation written by Sachin Laxman Bobade entitled "Supramolecular Association of Hydrogen-bonded Polybutadienes Functionalized with Ureidopyrimidone." I have examined the final electronic copy of this dissertation for form and content and recommend that it be accepted in partial fulfillment of the equirr ements for the degree of Doctor of Philosophy, with a major in Chemistry. Jimmy W. Mays, Major Professor We have read this dissertation and recommend its acceptance: Sheng Dai, Alexei P. Sokolov, Gajanan S. Bhat Accepted for the Council: Carolyn R. Hodges Vice Provost and Dean of the Graduate School (Original signatures are on file with official studentecor r ds.) Supramolecular Association of Hydrogen-bonded Polybutadienes Functionalized with Ureidopyrimidone A Dissertation Presented for the Doctor of Philosophy Degree The University of Tennessee, Knoxville Sachin Laxman Bobade December 2014 ii Dedications This thesis is dedicated to my late Grandparents, Parents and my Family. iii Acknowledgements First of all, I would like to thank, Dr. Durairaj Baskaran for his role as my mentor in scientific research at the NCL, Pune, India and at the University of Tennessee, Knoxville. He will always remain as an ideal scientist and teacher in my life, and unending source of inspiration in my research career. I would like to express my sincere gratitude to my advisor Prof. Jimmy Mays for giving me an opportunity to work in his group, his constant support, and encouragement. I thank both of them for their guidance throughout my graduate school. I would like to thank my research committee members for their valuable time, suggestions and guidance. I thank, Dr. Alexei Sokolov, Dr. Sheng. Dai, Dr. Gajanan Bhat and Dr. Jimmy Mays for being on my research committee. Journey of doctoral study seems to be never ending and at a time painful and frustrating, though a constant support and encouragement from family members and close friends provide a much needed comfort and a force to focus and eventually succeed. I would like to thank my family members, my sisters (Archana, and Kalpana), my brother (Nitin) and my wife Laxmi and my in-laws Mr. Mohan Avatade and Mrs. Mangala Avatade, for providing an essential dose of constant support and encouragement. I would especially thank all my relatives for their affection, love and inspiration to succeed in my life. I would like to thank Dr. Yangyang Wang, ORNL, for his help with polymer characterization and his thoughtful views into understanding polymer rheology. I would also like to thank Dr. Brad Lokitz, for help with polymer characterization at ORNL. Only a synthetic chemist can better understand the role of proper functioning polymer characterization lab. I really appreciate work of Mr. Tom Malmgren for his constant help with maintaining the PCL lab always ready to use, and running characterization of my samples. I would also like to thank other staff members at the chemistry department for their help during my stay at UTK. I thanks, Rhonda, Pam and Susan (administrative work); Jessica, Beverly, and Gail (chemstore), Gurley, and John (PC support), Art Patt, and Bo Bishop (glass workshop). iv Throughout my time in the graduate school at the University of Tennessee, Knoxville, I have been very fortunate to work with many talented and creative fellow graduate students in our research group. I want to thank ex- and current lab members, Holley Wade, Ravi Aggarwal, Justin Roop, Vikram Srivastava, Andrew Goodwin, Christopher Hurley, Weiyu Wang, Wei Lu, Xinyi Lu, Hongbo Feng, Benjamin Ripy, and Huiqun Wang for making my time pleasurable at UTK. I would like to thank Adam Imel, and Brad Miller for their help with polymer characterization. Alongwith graduate students, I also had privilege to work with fellow postdoc and research staff. I would like to thank them all, Dr. Shahinur Rahman, Dr. Suxiang Deng, Dr. Kostas Mischronis, Dr. Beomgoo Kang, and Dr. Namgoo Kang. I would like to thank Dr. Prakash Wadgaonkar, Mr. Shamal Menon, and Dr. R. A. Kulkarni for their support while my stay at NCL, Pune, India. I extend my thanks to my all friends at NCL, including group members of Dr. PPW group, and Dr. Baskaran group, for making my stay memorable at NCL. Non-covalent and covalent interactions play significant roles in a living matter. Covalent bond provides the essential chemical structure and makes backbone of a molecule and non-covalent bonding helps in supramolecular activities. Both are essential for functioning of a life and often not separable from each other. Similarly, during my doctoral study the presences of many people have helped me either directly or indirectly, which was vital for my growth as a good scientist and a good person. I would like to thank them all! Finally, I would like to thank my father (Mr. Laxman Bobade), and mother (Mrs. Hirabai Bobade). Without their hard work, struggle, sacrifice, and love, this day would not have been made possible. Sachin Bobade v Abstract Ureidopyrimidone (UPy) is a well-known self-complementary quadruple hydrogen bonding unit, extensively applied in the preparation of supramolecular polymers with enhanced physical properties. The property enhancement is assigned partly to linear chain extension and fibrillar nanophase separation due to secondary hydrogen bonding by urethane and urea linker, though a clear distinctive structure property relationship has not be reported. In this work, two distinct sets of UPy functional polymers, a series of monochelic polybutadienes (PBd) and telechelic polybutadienes, were synthesized and analyzed by solution and bulk characterization techniques to probe the role of polymer chain mobility and polarity on the UPy chain-end association. ω [omega]-UPy terminated polybutadiene was semi-solid waxy material, indicating association beyond dimers. Solution studies indicate the presence of star-like micelles that are in equilibrium with dimers. These aggregated micellar clusters have distinct endothermic transitions in differential scanning calorimetry (DSC). Atomic force microscopy (AFM) studies show an evidence of micellar-clusters forming associated parallel line-like structures on a mica surface with the well-defined order. A series of α [alpha], ω [omega]-di-UPy terminated polybutadienes and hydrogenated polybutadienes were synthesized, and their properties was evaluated as a function of 1,2-vinyl content. Telechelic UPy-PBd differs strongly in their physical properties, PBd with low Tg [glass transition temperature] (-90 °C) forms semi-solid and brittle material, whereas PBd with moderate Tg (-45 °C) gave strong thermoplastic elastomer. AFM images give parallel association of micellar clusters. Dynamics of micellar-cluster associated UPy domains with unassociated chain extended dimers lead to gelation at specific temperature depending on the characteristics of the linker precursor oligomers. Supramolecular gel transition temperature (TSG) was identified in rheological studies on various UPy telechelics. In addition, polystyrene and poly(n-butylacrylate) UPy telechelics were also prepared by copper (I) catalyzed alkyne azide coupling (CuAAC) “click” reaction. The triazole linker in these polymers interferes with the UPy association and reduces the size of the hydrogen bonded UPy aggregates, which was found to improve the physical property of the supramolecular polymers. An attempt was made to examine the role of polymer chain mobility and its polarity was used to correlate structure and property with reference to room temperature. vi Table of Contents Chapter 1: Ureidopyrimidone Based Supramolecular Polymers …………………………1 1.1 Background ....................................................................................................... 2 1.2 Significance of self-assembly ........................................................................... 3 1.3 Supramolecular polymerization ........................................................................ 4 1.3.1 Mechanism of the formation of supramolecular polymers.................... 5 1.3.2 Classification of supramolecular polymers ........................................... 8 1.4 Hydrogen bonded supramolecular polymers .................................................... 9 1.4.1 Multiple hydrogen bonding in bifunctional small molecules .............. 11 1.4.2 Multiple hydrogen bonding in telechelic oligomers ............................ 13 1.5 Nucleobases based supramolecular materials ................................................. 13 1.6 The need for high Ka system: Ureidopyrimidone
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