Multi‐stimuli‐responsive Polymers Based on Calix[4]arenes and Dibenzo‐18‐crown‐6‐ethers

Wiktorowicz, Szymon; Tenhu, Heikki; Aseyev, Vladimir

doi:10.1002/9781119157830.ch6

Cited by 2 publications

(1 citation statement)

References 190 publications

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“…The stimuli to achieve or manipulate polymer self-association (self-assembly) in aqueous solutions are most often changes in pH, ionic strength, temperature, and/or even mechanical stress [4]. Some polymers respond to a combination of two or more stimuli [5], which enables very effective creation of soft materials. Situation is even more complex in case that a polymer chain can acquire charge through ionization of its functional groups, which may lead to additional options for customizing properties, for example through viscosity increase.…”

Section: Introductionmentioning

confidence: 99%

Chain dynamics and intermolecular association in dilute aqueous solutions of isotactic and atactic Poly(Methacrylic acid): Effect of NaCl concentration

Sitar

Aseyev

Žagar

et al. 2019

Polymer

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Dynamic and static light scattering measurements were performed on isotactic and atactic forms of poly(methacrylic acid), iPMA and aPMA, respectively, in order to perform a wide survey of their molecular properties and chain dynamics in water as functions of tacticity, degree of neutralization, αN, and salt concentration, cs. The molecular parameters of PMA chains were analyzed at low αN and chain dynamics (diffusion coefficients and in this connection the polyelectrolyte slow mode behavior) at higher αN. The data revealed that both PMAs form microgel-like aggregates with a core-shell structure at low αN (= 0 and 0.25 for aPMA and iPMA, respectively). The distribution of the hydrophilic and hydrophobic functional groups within the aggregates and their compactness depended considerably on chain tacticity and for aPMA also on cs. Further, the effect of cs on the polyelectrolyte slow diffusion coefficient, Ds, of partly (0.25  αN < 1) or completely charged PMA polyions (αN = 1) was studied. In iPMA solutions, Ds was detected up to cs = 0.1 M, regardless of αN, whereas in aPMA solutions this cs value gradually decreased with decreasing N. These differences were also related to tacticity and through that to rigidity of the studied forms of PMA. It is argued that the segregation of uncharged and charged carboxyl groups is operative over the entire αN region in iPMA solutions.

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Section: Introductionmentioning

confidence: 99%

Chain dynamics and intermolecular association in dilute aqueous solutions of isotactic and atactic Poly(Methacrylic acid): Effect of NaCl concentration

Sitar

Aseyev

Žagar

et al. 2019

Polymer

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Conjugated Main Chain Azo‐Polymers Based on Polycyclic Aromatic Hydrocarbons

Wiktorowicz

Damlin

Salomäki

et al. 2019

Macro Chemistry & Physics

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A reductive coupling reaction employing sodium bis(2‐methoxyethoxy) aluminum hydride is used to prepare main chain azo‐polymers comprising of polycyclic aromatic hydrocarbons (naphthalene, anthraquinone, or fluorenone) from their dinitro‐derivatives. The azo‐bridges act as effective means of conjugation and all polymers exhibit differences in the ultra‐violet–visible light absorption and photoluminescence emission spectra depending on the degree of polymerization. Furthermore, in the case of poly(azofluorenone)s and poly(azoanthraquinone)s, these spectra may be modified by changes in the protonation state of the polymers. The lowest unoccupied molecular orbital and highest occupied molecular orbital energy levels and the band gap of poly(azoanthraquinone) are estimated from cyclic voltammetry data and UV–visible absorption of films.

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Multi‐stimuli‐responsive Polymers Based on Calix[4]arenes and Dibenzo‐18‐crown‐6‐ethers

Cited by 2 publications

References 190 publications

Chain dynamics and intermolecular association in dilute aqueous solutions of isotactic and atactic Poly(Methacrylic acid): Effect of NaCl concentration

Chain dynamics and intermolecular association in dilute aqueous solutions of isotactic and atactic Poly(Methacrylic acid): Effect of NaCl concentration

Conjugated Main Chain Azo‐Polymers Based on Polycyclic Aromatic Hydrocarbons

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