Potentiometric titrations of polymethacrylic acid

Katchalsky, A.; Spitnik, Pnina

doi:10.1002/pol.1947.120020504

Cited by 26 publications

(29 citation statements)

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“…The linear relationship between pH and log[(1 -α)/α], over a wide range of α values, gives a straight line for all the compounds studied ( Figure 6). This led to exclude any transition region between the coil to compact structure, as occurred for other class of polyelectrolytes [37,38]. The n value for the protonation of the imidazole nitrogen in the polyMHist and the corresponding copolymers, being related to the magnitude of the electrostatic interactions as well as being a measure of the hydrophilic influence [39], is always much lower than that reported for the acrylate analogue.…”

Section: Basicity Constants and Viscometrymentioning

confidence: 72%

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Stimuli-responsive poly(ampholyte)s containing L-histidine residues: synthesis and protonation thermodynamics of methacrylic polymers in the free and in the cross-linked gel forms

Casolaro¹,

Ito²,

Ishii³

et al. 2008

Express Polym. Lett.

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Abstract. Methacrylate-structured poly(ampholyte)s were synthesized in the homopolymer and copolymer forms starting from the N-methacryloyl-L-histidine (MHist) and the N-isopropylacrylamide (NIPAAm). They were also obtained in the cross-linked (hydrogel) form, showing a close thermodynamic behaviour as that shown by the corresponding soluble free polymer analogues. Viscometric data revealed that the minimum hydrodynamic volume of the polymer at its isoelectric point (pH 5) shifted to lower pHs as the NIPAAm content increased, and beyond a critical low MHist content the reduced viscosity decreased, even at low pHs. The phenomenon was attributed to hydrophobic forces between the isopropyl groups outweighing the repulsive electrostatic interactions of the polymer in the positively charged form. A similar behaviour was shown by the corresponding hydrogel. The latter also revealed a different phase transition phenomenon induced by external stimuli (temperature, pH, ionic strength, electric current) when compared to the acrylate-structured analogues. The polyMHist, as well as the corresponding monomer, was found for two days to be non toxic against the mouse osteoblasts (MC3T3-E1).

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Section: Basicity Constants and Viscometrymentioning

confidence: 72%

“…which has been checked experimentally for a number of polyelectrolytes [37,38]. The linear relationship between pH and log[(1 -α)/α], over a wide range of α values, gives a straight line for all the compounds studied ( Figure 6).…”

Section: Basicity Constants and Viscometrymentioning

confidence: 98%

Stimuli-responsive poly(ampholyte)s containing L-histidine residues: synthesis and protonation thermodynamics of methacrylic polymers in the free and in the cross-linked gel forms

Casolaro¹,

Ito²,

Ishii³

et al. 2008

Express Polym. Lett.

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“…pK was calculated according to the Henderson-Hasselbach equation [27]: Copolymers containing a high amount of carboxylic groups are not water soluble at some pH values (Table 1). This is a typical characteristic of polyampholytes as interaction between oppositely-charged functional groups decrease their hydrophilicity.…”

Section: Resultsmentioning

confidence: 99%

Polymeric Amines and Ampholytes Derived from Poly(acryloyl chloride): Synthesis, Influence on Silicic Acid Condensation and Interaction with Nucleic Acid

et al. 2017

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Polymeric amines are intensively studied due to various valuable properties. This study describes the synthesis of new polymeric amines and ampholytes by the reaction of poly(acryloyl chloride) with trimethylene-based polyamines containing one secondary and several (1-3) tertiary amine groups. The polymers contain polyamine side chains and carboxylic groups when the polyamine was in deficiency. These polymers differ in structure of side groups, but they are identical in polymerization degree and polydispersity, which facilitates the study of composition-properties relationships. The structure of the obtained polymers was confirmed with 13 C nuclear magnetic resonance infrared spectroscopy, and acid-base properties were studied with potentiometry titration. Placement of the amine groups in the side chains influences their acid-base properties: protonation of the amine group exerts a larger impact on the amine in the same side chain than on the amines in the neighboring side chains. The obtained polymers are prone to aggregation in aqueous solutions tending to insolubility at definite pH values in the case of polyampholytes. Silicic acid condensation in the presence of new polymers results in soluble composite nanoparticles and composite materials which consist of ordered submicrometer particles according to dynamic light scattering and electron microscopy. Polymeric amines, ampholytes, and composite nanoparticles are capable of interacting with oligonucleotides, giving rise to complexes that hold promise for gene delivery applications.

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“…For the determination of high molecular weight polyelectrolytes protonation constants [6 and references therein], the dependence of log K H on the degree of protonation (or on the degree of ionisation) must be taken into account; this implies the use of different calculation methods [38][39]. Nevertheless, in a previous work [23], a simple new approach to calculate the protonation constants, and enthalpy changes, of BPEI was proposed.…”

Section: Protonation Constantsmentioning

confidence: 99%

Sequestering ability of phytate towards protonated BPEI and other polyammonium cations in aqueous solution

Crea

Stefano

Porcino

et al. 2008

Biophysical Chemistry

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Please cite this article as: Francesco Crea, Concetta De Stefano, Nunziatina Porcino, Silvio Sammartano, Sequestering ability of phytate towards protonated BPEI and other polyammonium cations in aqueous solution, Biophysical Chemistry (2008Chemistry ( ), doi: 10.1016Chemistry ( /j.bpc.2008 This is a PDF file of an unedited manuscript that has been accepted for publication. As a service to our customers we are providing this early version of the manuscript. The manuscript will undergo copyediting, typesetting, and review of the resulting proof before it is published in its final form. Please note that during the production process errors may be discovered which could affect the content, and all legal disclaimers that apply to the journal pertain. A C C E P T E D M A N U S C R I P T ACCEPTED MANUSCRIPT AbstractThe interaction between protonated branched poly(ethylenimine) [BPEI] and phytate (1,2,3,4,5,6 hexakis (di-hydrogen phosphate) myo-inositol) [Phy] was studied potentiometrically. The measurements were carried out at t = 25 °C and at low ionic strength values, without addition of supporting electrolyte, to avoid interferences with other anions and cations. In order to simplify the data treatment, BPEI was considered as a simple tetramine. Different species Phy(BPEI)H j , with j = 6,7,8, and Phy(BPEI) 2 H 7 were found, having quite high stability. The ability of phytate to sequester BPEI was quantified by considering the parameter pL 50 , namely the concentration (-log [Phy] tot ) necessary to bind 50% of polyammonium cation (as trace). In our experimental conditions, for the system phytate-BPEI-proton we have pL 50 = 7.01, at pH = 7.4 and I = 0.04 mol L -1 . As for other phytate-polyammonium cation systems, the stability of the phytate-BPEI species is strictly proportional to the charges involved in the formation reactions. Therefore, it was possible to calculate the free energy contribution per bond, 0 b G Δ = 4.4±0.4 kJ mol -1 . The dependence on temperature and ionic strength of the stability of phytate-low/high molecular weight polyammonium cations species, was studied using some semiempirical equations and enthalpy data for the protonation of both components. The dependence on temperature of the stability is quite low and the variation of pL 50 in the range 15 ≤ t/°C ≤ 37 is less than 0.5 log units. On the contrary, the effect of ionic strength is highly significant, with a lowering of pL 50 of ≈ 2 log units (I = 0 to 0.15 mol L -1 ).

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Potentiometric titrations of polymethacrylic acid

Cited by 26 publications

References 0 publications

Stimuli-responsive poly(ampholyte)s containing L-histidine residues: synthesis and protonation thermodynamics of methacrylic polymers in the free and in the cross-linked gel forms

Stimuli-responsive poly(ampholyte)s containing L-histidine residues: synthesis and protonation thermodynamics of methacrylic polymers in the free and in the cross-linked gel forms

Polymeric Amines and Ampholytes Derived from Poly(acryloyl chloride): Synthesis, Influence on Silicic Acid Condensation and Interaction with Nucleic Acid

Sequestering ability of phytate towards protonated BPEI and other polyammonium cations in aqueous solution

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