Interaction of partially ionized poly(acrylic acid) with a surfactant counterion at constant pH values

2001 ◽  
Vol 279 (9) ◽  
pp. 858-864 ◽  
Author(s):  
H. Katsuura ◽  
H. Kawamura ◽  
M. Manabe ◽  
H. Maeda
1991 ◽  
Vol 1 (6) ◽  
pp. 637-650 ◽  
Author(s):  
A. Moussaid ◽  
J. P. Munch ◽  
F. Schosseler ◽  
S. J. Candau

2014 ◽  
Vol 12 (4) ◽  
pp. 476-479 ◽  
Author(s):  
Małgorzata Wiśniewska ◽  
Teresa Urban ◽  
Agnieszka Nosal-Wiercińska ◽  
Vladimir Zarko ◽  
Vladimir Gun’ko

AbstractThe influence of anionic poly(acrylic acid) — PAA addition on the stability of synthesized silica, alumina and mixed silica-alumina suspensions as a function of solution pH was studied. The turbidimetry method was used to monitor the changes of the examined systems stability over time. The calculated stability coefficients enabled estimation of polymer adsorption influence on stability of metal oxide suspension. It was shown that the alumina suspension without the polymer is the most unstable at the pH values 6 and 9, whereas the silica polymer was most unstable at pH 3. PAA with higher molecular weight (240 000) is a relatively effective stabilizer of all investigated adsorbents (except silica at pH 3). These properties of poly(acrylic acid) are highly desirable in many branches of industry (e.g. production of cosmetics, pharmaceuticals, paints) where polymers are widely used as effective stabilizers of colloidal suspensions.


Polymers ◽  
2020 ◽  
Vol 12 (3) ◽  
pp. 566
Author(s):  
Zun Wang ◽  
Kaimin Chen ◽  
Chen Hua ◽  
Xuhong Guo

Adsorption and desorption of proteins on biomaterial surfaces play a critical role in numerous biomedical applications. Spherical diblock polymer brushes (polystyrene with photoiniferter (PSV) as the core) with different block sequence, poly(acrylic acid)-b-poly(N-(2-hydroxyethyl) acrylamide) (PSV@PAA-b-PHEAA) and poly(N-(2-hydroxyethyl) acrylamide)-b-poly(acrylic acid) (PSV@PHEAA-b-PAA) were prepared via surface-initiated photoiniferter-mediated polymerization (SI-PIMP) and confirmed by a series of characterizations including TEM, Fourier transform infrared (FTIR) and elemental analysis. Both diblock polymer brushes show typical pH-dependent properties measured by dynamic light scattering (DLS) and Zeta potential. It is interesting to find out that conformation of PSV@PAA-b-PHEAA uniquely change with pH values, which is due to cooperation of electrostatic repulsion and steric hindrance. High-resolution turbidimetric titration was applied to explore the behavior of bovine serum albumin (BSA) binding to diblock polymer brushes, and the protein adsorption could be tuned by the existence of PHEAA as well as apparent PAA density. These studies laid a theoretical foundation for design of diblock polymer brushes and a possible application in biomedical fields.


2020 ◽  
Vol 2020 ◽  
pp. 1-12
Author(s):  
Muhammad Asad Abbas ◽  
Shehla Mushtaq ◽  
Waqas A. Cheema ◽  
Hazim Qiblawey ◽  
Shenmin Zhu ◽  
...  

The grafting of pH-responsive poly(acrylic acid) (PAA) brushes was carried out on the surface of a commercial TFC-PA membrane using surface-initiated atom transfer radical polymerization (SI-ATRP). Poly(t-butyl acrylate) was polymerized through the SI-ATRP method followed by its acid hydrolysis to form PAA hydrophilic polymer brushes. Surface morphology, permeation flux, salt rejection, and pore sizes were investigated. The contact angle for water was reduced from 50° for a pristine membrane to 27° for the modified membrane due to a modification with the hydrophilic functional group and its brush on membrane surfaces. The flux rate also increased noticeably at lower pH values relative to higher pH for the modified membranes, while the flux remains stable in the case of pristine TFC-PA membranes. There is slight transition in the water flux rate that was also observed when going from pH values of 3 to 5. This was attributed to the pH-responsive conformational changes for the grafted PAA brushes. At these pH values, ionization of the COOH group takes place below and above pKa to influence the effective pore dimension of the modified membranes. At a lower pH value, the PAA brushes seem to permit tight structure conformation resulting in larger pore sizes and hence more flux. On the other hand, at higher pH values, PAA brushes appeared to be in extended conformation to induce smaller pore sizes and result in less flux. Further, pH values were observed to not significantly affect the NaCl salt rejection with values observed in between 98.8% and 95% and close to that of the pristine TFC-PA membranes. These experimental results are significant and have immediate implication for advances in polymer technology to design and modify the “switchable membrane surfaces” with controllable charge distribution and surface wettability, as well as regulation of water flux and salt.


Nanomaterials ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 235
Author(s):  
Felipe Díaz-Soler ◽  
Carlos Rodriguez-Navarro ◽  
Encarnación Ruiz-Agudo ◽  
Andrónico Neira-Carrillo

In this work, calcium oxalate (CaOx) precursors were stabilized by poly(acrylic acid) (PAA) as an additive under in vitro crystallization assays involving the formation of pre-nucleation clusters of CaOx via a non-classical crystallization (NCC) pathway. The in vitro crystallization of CaOx was carried out in the presence of 10, 50 and 100 mg/L PAA by using automatic calcium potentiometric titration experiments at a constant pH of 6.7 at 20 °C. The results confirmed the successful stabilization of amorphous calcium oxalate II and III (ACOII and ACO III) nanoparticles formed after PNC in the presence of PAA and suggest the participation and stabilization of polymer-induced liquid-precursor (PILP) in the presence of PAA. We demonstrated that PAA stabilizes CaOx precursors with size in the range of 20–400 nm. PAA additive plays a key role in the in vitro crystallization of CaOx stabilizing multi-ion complexes in the pre-nucleation stage, thereby delaying the nucleation of ACO nanoparticles. Indeed, PAA additive favors the formation of more hydrated and soluble phase of ACO nanoparticles that are bound by electrostatic interactions to carboxylic acid groups of PAA during the post-nucleation stage. These findings may help to a better understanding of the pathological mineralization resulting in urolithiasis in mammals.


1998 ◽  
Vol 13 (8) ◽  
pp. 2245-2250 ◽  
Author(s):  
Jau-Ho Jean ◽  
Hong-Ren Wang

Ammonium salt of poly(acrylic acid) (PAA-NH4) has been used to stabilize aqueous BaTiO3 suspensions at various pH values. Adsorption of PAA-NH4 causes the zeta potential to become more negative, although this effect becomes less dramatic as the pH increases. The concentration of PAA-NH4 required to stabilize aqueous BaTiO3 suspensions decreases with increasing pH. The critical amount of PAA-NH4 as a function of pH is plotted in a stability map, as determined by adsorption, rheology, and sedimentation studies.


2020 ◽  
Vol 8 (38) ◽  
pp. 13368-13374
Author(s):  
Muhammad Umair Khan ◽  
Gul Hassan ◽  
Jinho Bae

This paper proposes a novel soft ionic liquid (IL) electrically functional device that displays resistive memory characteristics using poly(acrylic acid) partial sodium salt (PAA-Na+:H2O) solution gel and sodium hydroxide (NaOH) in a thin polydimethylsiloxane (PDMS) cylindrical microchannel.


Sign in / Sign up

Export Citation Format

Share Document