Potentiometric behavior of polymethacrylic acid

Leyte, J. C.; Mandel, M.

doi:10.1002/pol.1964.100020429

Cited by 154 publications

(158 citation statements)

References 11 publications

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“…Because most HM polymers are sensitive to pH and ionic strength, regulation of these variables can also be used to manipulate conformation and solution rheology. [15][16][17][18] To explore the determining factor for HM polymer conformation in solution, an intermediate modified, poly(maleic acid/ alkyl vinyl ether) homologue, namely, poly(maleic acid/octyl vinyl ether) (PMAOVE) (Chart 1), labeled with pyrene, was studied using fluorescence spectroscopy. To isolate the effect of hydrophobic substitution on the solution behavior, a homologue without the hydrophobic chain, pyrene-labeled poly(maleic acid/methyl vinyl ether) (PMAMVE) (Chart 1), was also studied.…”

Section: Introductionmentioning

confidence: 99%

Conformational Changes of Pyrene-Labeled Polyelectrolytes with pH: Effect of Hydrophobic Modifications

Deo

Somasundaran

et al. 2005

J. Phys. Chem. B

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Structural changes of pyrene-labeled and unlabeled poly(maleic acid/octyl vinyl ether) (PMAOVE) and poly-(maleic acid/methyl vinyl ether) (PMAMVE) with changes in pH have been investigated in this study. The changes in the photophysical properties of pyrene are interpreted to investigate uncoiling or swelling of the polymeric chains with pH. The vibrational fine structure of the pyrene fluorescence (I 3 /I 1 ) and the ratio between excimer and monomer fluorescence (I e /I m ) of both pyrene-labeled and unlabeled PMAMVE and PMAOVE suggest that, at pH 4, the polymers are in the coiled form and PMAOVE forms hydrophobic nanodomains. An increase in pH ionizes a number of COOH groups on both PMAMVE and PMAOVE, which leads to the stretching or swelling of the polymers.

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Section: Introductionmentioning

confidence: 99%

Conformational Changes of Pyrene-Labeled Polyelectrolytes with pH: Effect of Hydrophobic Modifications

Deo

Somasundaran

et al. 2005

J. Phys. Chem. B

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“…5 Also, the pK remains constant over a range of pH after an initial increase before resuming its rise with further increase in pH. 6 This has been interpreted 7 as indicating that within the pH range of the pK plateau there is a gradual transition from one to another local conformation with no significant change in the overall expansion of the polyion. Only when this transition is complete does the long-range Coulombic repulsion between the ionic charges with increasing pH lead to the large expansion of the PMA.…”

Section: Introductionmentioning

confidence: 99%

Chemically Induced Dynamic Electron Polarization Studies of a pH-Dependent Free Radical Cage Formed in a Photoinitiator Labeled Poly(methacrylic acid)

Maliakal¹,

Weber²,

Turro³

et al. 2002

Macromolecules

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Time-resolved electron spin resonance (TR-ESR) has been used to investigate the effect of pH-dependent poly(methacrylic acid) clustering on the radical pair generated from photolysis of a poly(methacrylic acid) acid sample randomly labeled with the common R-hydroxy ketone photoinitiator 1. The TR-ESR spectra for the ketyl radical show a dramatic change in electron spin polarization mechanism, from a predominantly triplet mechanism (TM) at low pH (below 6) to a predominantly radical pair mechanism (RPM) at high pH (above 7). The ratio of RPM/TM polarization exhibits a sigmoidal behavior as a function of pH which passes through an inflection point at pH 6.9 ( 0.1. The inflection point agrees well with previous estimates for pH-dependent cluster opening in poly(methacrylic acid). These results indicate that the pH-dependent cluster is capable of forming a cage around the geminate radical pair which restricts its motion at low pH. At higher pH, the cluster opens, allowing the ketyl radical to escape the pair. Studies of the benzoyl partner in the radical pair, which is attached covalently to the polymer backbone, indicate differing environments within the cluster even at pH below cluster opening. This study represents the first application of TR-ESR and electron spin polarization (ESP) to the problem of pH-dependent clustering and reveals new features of the pH-dependent poly(methacrylic acid) cluster.

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“…It is known that Figure 1.Dependence of pH on α for 0.1wt % polymer solutions: (□) P(MAAb-MMA) block coplolymer; (◇) MAA-EA random copolymer without solublization; (△) MAA-EA random copolymer with solublization the intrinsic dissociation constant K 0 is related to the standard change of the free energy (∆G 0 ) for the dissociation of H + from an isolated acid group, whereas the apparent dissociation constant K a contains an additional contribution, ∆G el , which is related to the extra work to overcome the electrostatic attraction between the H + and ~COO -when transferring the proton from the poly-anion to the bulk. [18][19][20] Thus pK a can be written as a sum of two terms:…”

Section: B Potentiometric and Conductometric Titrationmentioning

confidence: 99%

Association Behavior of Poly(methacrylic acid)-block-poly(methyl methacrylate) in Aqueous Medium: Potentiometric and Laser Light Scattering Studies

et al. 2002

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Abstract-Atom transfer radical polymerisation (ATRP) technique was used to synthesize poly(methacrylic acidblock-methyl methacrylate) (P(MAA 102 -b-MMA 10 )) copolymer in order to study the aggregation behavior in aqueous solution over the course of neutralization. A combination of static and dynamic light scattering (SLS, DLS) and potentiometric titration techniques were used to investigate the size and shape of the micelle at various degrees of neutralization. The hydrodynamic radius (R h ) determined from dynamic light scattering increases from ∼26nm (for unneutralized) to ∼42nm (for completely neutralized sample). Both potentiometric and laser light scattering studies indicate the formation of a core shell micelle. The weighted average molecular weights of the polymer and micelle are 1.18x10 4 and 2.25 x 10 5 g/mol respectively, which suggests that the aggregation number of the micelle is ~20.

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Potentiometric behavior of polymethacrylic acid

Cited by 154 publications

References 11 publications

Conformational Changes of Pyrene-Labeled Polyelectrolytes with pH: Effect of Hydrophobic Modifications

Conformational Changes of Pyrene-Labeled Polyelectrolytes with pH: Effect of Hydrophobic Modifications

Chemically Induced Dynamic Electron Polarization Studies of a pH-Dependent Free Radical Cage Formed in a Photoinitiator Labeled Poly(methacrylic acid)

Association Behavior of Poly(methacrylic acid)-block-poly(methyl methacrylate) in Aqueous Medium: Potentiometric and Laser Light Scattering Studies

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