Preparation of oligoamide‐ended poly(ethylene glycol) and hydrogen‐bonding‐assisted formation of aggregates and nanoscale fibers

Hua, Fengjun; Yang, Xuefei; Gong, Bing; Ruckenstein, Eli

doi:10.1002/pola.20591

Cited by 17 publications

(8 citation statements)

References 26 publications

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“…The peaks at 378 and 540 nm are assigned to the π–π* benzenoid transition and the benzenoid‐to‐quinoid excitonic transtion, respectively. Comparing the literatures, it shows a strong blue‐shift, which is associated with a shortening of the conjugation length, and it is consistent with the result of elemental analysis 26–28…”

Section: Resultssupporting

confidence: 89%

Synthesis of achiral PEG‐PANI rod‐coil block copolymers and their helical superstructures

Yan

Wei

2007

J. Polym. Sci. A Polym. Chem.

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Poly(ethylene glycol) (PEG) was modified with aniline groups at both the end, and then PEG‐PANI rod‐coil block polymers have been synthesized by polymerization of the aniline with the aniline‐modified PEG. FTIR, NMR, and elemental analysis provided the chemical strucutre of the as‐prepared polymers. The achiral rod‐coil copolymer could form different superstructures by means of self‐assembly when adding diethyl ether into its THF solution and the length of PANI segments is a key factor to the superstructures. AFM measurements revealed that they form spring‐like helical superstructures from the short PANI‐containing copolymers while these form fibrous helical superstructures from the longer PANI‐containing copolymer. A possible mechanism of the helical superstructures is suggested in this article and the driving force is believed the π–π stacking of the rigid segment of the copolymers. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 12–20, 2008

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Section: Resultssupporting

confidence: 89%

Synthesis of achiral PEG‐PANI rod‐coil block copolymers and their helical superstructures

Yan

Wei

2007

J. Polym. Sci. A Polym. Chem.

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“…For example, extending the length of the PEG chains from 2 to 111 ethylene glycol units (i.e., changing from C2-Me to C4-Me ) only slowed k on by a factor of 2 at the most (see Table and compare entries 2 and 4, 6 and 8, 9 and 11, 14 and 16). Thus, even with the smallest N -methyl substituent and longest PEG chain, there is no evidence that any intermolecular or intramolecular PEG chain interactions , are a kinetically significant factor.…”

Section: Resultsmentioning

confidence: 99%

High Affinity Macrocycle Threading by a Near-Infrared Croconaine Dye with Flanking Polymer Chains

2016

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Croconaine dyes have narrow and intense absorption bands at ~800 nm, very weak fluorescence, and high photostabilities, which combine to make them very attractive chromophores for absorption-based imaging or laser heating technologies. The physical supramolecular properties of croconaine dyes have rarely been investigated, especially in water. This study focuses on a molecular threading process that encapsulates a croconaine dye inside a tetralactam macrocycle in organic or aqueous solvent. Macrocycle association and rate constant data are reported for a series of croconaine structures with different substituents attached to the ends of the dye. The association constants were highest in water (Ka ~109 M−1), and the threading rate constants (kon) increased in the solvent order H2O > MeOH > CHCl3. Systematic variation of croconaine substituents located just outside the croconaine/macrocycle complexation interface hardly changed Ka but had a strong influence on kon. A croconaine dye with N-propyl groups at each end of the structure exhibited a desirable mixture of macrocycle threading properties; that is, there was rapid and quantitative croconaine/macrocycle complexation at relatively high concentrations in water, and no dissociation of the pre-assembled complex when it was diluted into a solution of fetal bovine serum, even after laser induced photothermal heating of the solution. The combination of favorable near-infrared absorption properties and tunable mechanical stability makes threaded croconaine/macrocycle complexes very attractive as molecular probes or as supramolecular composites for various applications in absorption-based imaging or photothermal therapy.

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“…Among these approaches, intermolecular H‐bonding is simply acquired by complexation of H‐bonded donor (H‐donor) carboxylic (or benzoic) acid groups with H‐bonded acceptor (H‐acceptor) pyridyl moieties. Several series of H‐bonded polymer complexes and side‐chain LC polymers through intermolecular H‐bonding (interaction between benzoic acid and pyridine) have been reported lately 18–30…”

Section: Introductionmentioning

confidence: 99%

Study of supramolecular side‐chain and cross‐linking polymers by complexation of various H‐donor acids with H‐acceptor copolymers containing pendent carbazole and fluorescent pyridyl units

Liang

Lin

2009

J. Polym. Sci. A Polym. Chem.

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Two H‐bonded acceptor (H‐acceptor) homopolymers 14 and 17 were successfully prepared by polymerization of fluorescent pyridyl monomers PBT and PBOT (12 and 13), which were synthesized via Sonogashira coupling and Wittig‐Horner reactions. To increase the glass transition temperatures as well as reduce the π‐π stacking of the photoluminescent (PL) H‐acceptor copolymers and their H‐bonded polymer complexes, fluorescent monomers 12 and 13 were copolymerized with N‐vinylcarbazole monomer CAZ (23) to produce H‐acceptor copolymers 15–16 and 18–19. Supramolecular side‐chain and crosslinking polymers (i.e., H‐bonded polymer complexes) obtained by complexation of light‐emitting H‐acceptor polymers 14–19 with various proton donor (H‐donor) acids 20–22 were further characterized by DSC, POM, FTIR, XRD, and PL measurements. The mesomorphic properties can be tuned from the nematic phase in H‐acceptor homopolymers (14 and 17) to the tilted smectic C phase in their H‐bonded polymer complexes (14/20–21 and 17/20–22) by the introduction of H‐donor acids (20–22). Moreover, the PL properties of light‐emitting H‐acceptor polymers can be adjusted not only by the central structures of the conjugated pyridyl cores but also by their surrounding nonfluorescent H‐donor acids. In general, redder shifts of PL emissions in H‐bonded polymer complexes occurred when the light‐emitting H‐acceptor polymers were complexed with H‐donors having smaller pKa values. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 2734–2753, 2009

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Preparation of oligoamide‐ended poly(ethylene glycol) and hydrogen‐bonding‐assisted formation of aggregates and nanoscale fibers

Cited by 17 publications

References 26 publications

Synthesis of achiral PEG‐PANI rod‐coil block copolymers and their helical superstructures

Synthesis of achiral PEG‐PANI rod‐coil block copolymers and their helical superstructures

High Affinity Macrocycle Threading by a Near-Infrared Croconaine Dye with Flanking Polymer Chains

Study of supramolecular side‐chain and cross‐linking polymers by complexation of various H‐donor acids with H‐acceptor copolymers containing pendent carbazole and fluorescent pyridyl units

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