Novak, Bruce M.
Permanent URI for this collectionhttps://hdl.handle.net/10735.1/4017
Bruce Novak holds the Distinguished Chair in Natural Sciences and Mathematics and serves as Dean of the school. His research involves polymers and currently encompasses projects in materials chemistry, including macromolecular chirality, optical switches and molecular machines.
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Item Self-Assembling Morphologies Obtained from Helical Polycarbodiimide Copolymers and Their Triazole Derivatives(MyJOVE Corp.) Kulikov, Oleg V.; Siriwardane, Dumindika A.; McCandless, Gregory T.; Mahmood, Samsuddin F.; Novak, Bruce M.; 0000 0000 8413 1147 (Novak, BM); 116300023 (Novak, BM); Kulikov, Oleg V.; Siriwardane, Dumindika A.; McCandless, Gregory T.; Mahmood, Samsuddin F.; Novak, Bruce M.A facile method for the preparation of polycarbodiimide-based secondary structures (e. g., nano-rings, "craters," fibers, looped fibers, fibrous networks, ribbons, worm-like aggregates, toroidal structures, and spherical particles) is described. These aggregates are morphologically influenced by extensive hydrophobic side chain-side chain interactions of the singular polycarbodiimide strands, as inferred by atomic force microscopy (AFM) and scanning electron microscopy (SEM) techniques. Polycarbodiimide-g-polystyrene copolymers (PS-PCDs) were prepared by a combination of synthetic methods, including coordination-insertion polymerization, copper(I)-catalyzed azide alkyne cycloaddition (CuAAC) "click" chemistry, and atom transfer radical polymerization (ATRP). PS-PCDs were found to form specific toroidal architectures at low concentrations in CHCl3. To determine the influence of a more polar solvent medium (i. e., THF and THF/EtOH) on polymer aggregation behavior, a number of representative PS-PCD composites have been tested to show discrete concentration-dependent spherical particles. These fundamental studies are of practical interest to the development of experimental procedures for desirable architectures by directed self-assembly in thin film. These architectures may be exploited as drug carriers, whereas other morphological findings represent certain interest in the area of novel functional materials.Item Synthesis and Characterization of a Novel Fluorinated Bismaleimide via a Nucleophilic Addition-Elimination Reaction and its Polymeric Networks(Royal Society of Chemistry, 1905-07-07) Wu, Jingbo; Xi, Yang; McCandless, Gregory T.; Kulikov, Oleg V.; Menon, Remya; Novak, Bruce M.; Wu, Jingbo; Xi, Yang; McCandless, Gregory T.; Kulikov, Oleg V.; Menon, Remya; Novak, Bruce M.The commercially available octafluorocyclopentene (OFCP) as both a fluorinated building block and a linker has been successfully utilized to prepare a new fluorinated bismaleimide monomer OFCP-BMIvia a nucleophilic addition-elimination reaction. The resulting OFCP-BMI is characterized by 1H, 13C, 19F nuclear magnetic resonance (NMR) spectroscopy, attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR), and high resolution mass spectrometry. The monomer OFCP-BMI reacts with a free radical initiator or self-cures to prepare its resins. No obvious glass transition temperature (Tg) below 260°C was observed for the self-curing resin suggesting that a highly cross-linked polymeric network was formed. The self-curing resin exhibits excellent thermal stability with the on-set weight loss temperature (Ton-setd) of 445°C and a 50% char yield at 800°C under a nitrogen atmosphere. The resin obtained by a free radical polymerization process exhibits less thermal stability and a lower char yield than the self-curing resin due to its lower cross-linking density. The self-curing resin exhibits a low dielectric constant (Dk = 2.5).Item Utilization of a Meldrum's Acid Towards Functionalized Fluoropolymers Possessing Dual Reactivity for Thermal Crosslinking and Post-Polymerization Modification(2015-04-30) Wu, Jingbo; Iacono, Scott T.; McCandless, Gregory T.; Smith, Dennis W., Jr.; Novak, Bruce M.; 253728855 (Smith, DW); 116300023 (Novak, BM); Wu, Jingbo; Iacono, Scott T.; McCandless, Gregory T.; Smith, Dennis W., Jr.; Novak, Bruce M.New thermally cross-linkable and/or post-functionalizable perfluorocyclobutyl (PFCB) polymers containing Meldrum's acid moieties have been successfully prepared via the thermal cyclopolymerization of a new Meldrum's acid functionalized aromatic trifluorovinyl ether (TFVE) monomer.Item A Semiconducting Liquid Crystalline Block Copolymer Containing Regioregular Poly-(3-hexylthiophene) and Nematic Poly(n-hexyl Isocyanate) and its Application in Bulk Heterojunction Solar Cells(Royal Soc Chemistry, 2014-08-06) Bhatt, Mahesh P.; Du, Jia; Rainbolt, Elizabeth A.; Pathiranage, Taniya M. S. K.; Huang, Peishen; Reuther, James F.; Novak, Bruce M.; Biewer, Michael C.; Stefan, Mihaela C.; 0000 0000 8413 1147 (Novak, BM); 98037603 (Novak, BM); 55039821 (Stefan, MC); Novak, Bruce M.; Biewer, Michael C.; Stefan, Mihaela C.A liquid crystalline diblock copolymer containing regioregular poly(3-hexylthiophene) (P3HT) and poly-(n-hexyl isocyanate) (PHIC) was synthesized by the combination of Grignard metathesis polymerization (GRIM) and titanium mediated coordination polymerization methods. The poly(3-hexylthiophene)-b-poly(n-hexyl isocyanate) (P3HT-b-PHIC) diblock copolymer used in this study contained ~10 mol% of P3HT and ~90 mol% of PHIC. The diblock copolymer displayed solvatochromism in THF-water and THF-methanol mixtures. The field-effect mobilities of the synthesized block copolymer were measured in bottom gate-bottom contact organic field-effect transistors (OFETs). The surface morphology of the polymer thin film was investigated in the channel region of the OFET devices by tapping mode atomic force microscopy (TMAFM). The diblock copolymer displayed nanostructured morphology in thin film and had good mobility despite the low content of the semiconducting P3HT block. The diblock copolymer was also used as an additive to improve the performance of P3HT/PCBM bulk heterojunction (BHJ) solar cells. Liquid crystalline characteristics of the diblock copolymer were examined by cross-polarizing microscopy and X-ray diffraction.