Influence of charge density on rheological properties and dehydration dynamics of weakly charged poly(N-isopropylacrylamide) during phase transition

Ye, Yilan; Shangguan, Yonggang; Song, Yihu; Zheng, Qiang

doi:10.1016/j.polymer.2014.03.057

Cited by 11 publications

(6 citation statements)

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“…23,27,28 However, some literatures gave opposite conclusion. 24,29,30 Unfortunately, the systematic investigations on the properties of charged P(NIPAM-co-MAA) microgel suspension and even the structural evolution and dehydration dynamics during volume phase transition are still scarce. Thus, far, the effect of charged groups on the microscopic mechanism of the transition is ambiguous and poorly understood.…”

Section: Introductionmentioning

confidence: 99%

“…For example, the result of Wu indicates that the VPTT of poly( N -isopropylacrylamide- co -acrylic acid) P(NIPAM- co -AA) hydrogel is slightly higher than that of PNIPAM. In other words, the charge density within the PNIPAM network may affect the VPTT of P(NIPAM- co -MAA) microgel and its dynamic or rheological properties. − …”

Section: Introductionmentioning

confidence: 99%

“…Furthermore, the effective charge density of microgel depends not only on the amount of charged groups but also on the pH and the ionic strength of solutions, which makes the relationship between volume phase transition and effective charge density more complex. For charged P(NIPAM- co -MAA) microgel, some studies have shown that the volume phase transition becomes discontinuous with increasing amount of charged groups. ,, However, some literatures gave opposite conclusion. ,, Unfortunately, the systematic investigations on the properties of charged P(NIPAM- co -MAA) microgel suspension and even the structural evolution and dehydration dynamics during volume phase transition are still scarce. Thus, far, the effect of charged groups on the microscopic mechanism of the transition is ambiguous and poorly understood.…”

Section: Introductionmentioning

confidence: 99%

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Influence of Charged Groups on the Structure of Microgel and Volume Phase Transition by Dielectric Analysis

Yang

Zhao

et al. 2016

Macromolecules

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The thermally sensitive charged poly(N-isopropylacrylamide-co-methacrylic acid) (P(NIPAM-co-MAA)) spherical microgel was prepared and their temperature-dependent volume phase transition behavior was systematically studied by analyzing the dielectric spectroscopy theoretically over a frequency range from 40 Hz to 110 MHz. It was found that the dielectric relaxation of the charged P(NIPAM-co-MAA) microgel drastically changed between 30 and 35 °C, and was significantly different from that of neutral PNIPAM microgels recently published in Soft Matter. The relaxation mechanism was speculated and the relaxation parameters were fitted after successfully eliminating the electrode polarization at low-frequency. On the basis of this, the differences in the structure, swelling ability and dehydration dynamics between charged P(NIPAM-co-MAA) and neutral PNIPAM microgels were compared. Although both of the two microgels showed the same changing trend around the volume phase transition temperature (VPTT), VPTT of charged P(NIPAM-co-MAA) microgels is less markedly than that of neutral PNIPAM. This suggests that the interaction between the PNIPAM chains and the solvent was changed significantly because of the introduction of charged groups. The volume phase transition behavior of P(NIPAM-co-MAA) microgels controlled by a delicate balance between the hydrophobic attraction of NIPAM and the electrostatic repulsion of the carboxylate group of methacrylic acid (MAA). These interactions are the essential reasons of the changes of the charged microgels in structure, swelling ability, and dehydration dynamics.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Influence of Charged Groups on the Structure of Microgel and Volume Phase Transition by Dielectric Analysis

Yang

Zhao

et al. 2016

Macromolecules

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“…The rheological behavior of resins is essential in understanding the processability and structure–property relationships, which has a significance to its industrial applications. − The rheology of the resin depends upon various factors such as molecular weight distribution, monomer distribution, molecular weight of the material, presence of hydrophilic and hydrophobic functional groups, and macrostructure of the chains . The rheological properties of the resins synthesized by different methods were evaluated from the flow curves taken at 25 °C.…”

Section: Resultsmentioning

confidence: 99%

Comparative Study of Different Methods of Synthesis and Their Effect on the Thermomechanical Properties of a Halogenated Epoxy-Based Flame-Retardant Resin

Fayaz

Peerzada

Ganaie³

2021

ACS Omega

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The work presented in this paper deals with the comparative synthesis of diglycidyl ether-based tetrabromobisphenol-A(TBBPA) using both conventional and nonconventional methods in order to explore materials for better industrial applications with respect to effective yield, cost, and time consideration. The conventional method involved the polycondensation of TBBPA and epichlorohydrin in the presence of an alkali catalyst. The nonconventional routes adopted for the synthesis of the material involved ultrasonication, microwave irradiation, and UV light exposure. The Fourier transform infrared spectroscopy spectra of all the synthesized materials of the resin were found to be identical, and the X-ray diffraction analysis showed the material as amorphous. The mechanical studies of the resins revealed that all these resins synthesized by different methods are strong and possess high viscosity. Based on the overall thermal, rheological, and excellent hydrophobic properties, it can serve as an excellent flame retardant.

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“…indicate that the volume phase transition temperature (VPTT) of poly( N -isopropylacrylamide- co -acrylic acid) hydrogel is slightly higher than that of PNIPAM. Moreover, the charge density within the PNIPAM may affect the VPTT of P(NIPAM- co -MAA) microgel and also its dynamic or rheological properties. − …”

Section: Introductionmentioning

confidence: 99%

Comprehensive Computational and Experimental Analysis of Biomaterial toward the Behavior of Imidazolium-Based Ionic Liquids: An Interplay between Hydrophilic and Hydrophobic Interactions

et al. 2017

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To provide insights into the aggregation behavior, hydration tendency and variation in phase transition temperature produced by the addition of ionic liquids (ILs) to poly(N-isopropylacrylamide) (PNIPAM) aqueous solution, systematic physicochemical studies, and molecular dynamic simulations were carried out. The influence of ILs possessing the same [Cl] anion and a set of cations [Cmim] with increasing alkyl chain length such as 1-ethyl-3-methylimidazolium ([Emim]), 1-allyl-3-methylimidazolium ([Amim]), 1-butyl-3-methylimidazolium ([Bmim]), 1-hexyl-3-methylimidazolium ([Hmim]), 1-benzyl-3-methylimidazolium ([Bzmim]), and 1-decyl-3-methylimidazolium ([Dmim]) on the phase transition of PNIPAM was monitored by the aid of UV-visible absorption spectra, fluorescence intensity spectra, viscosity (η), dynamic light scattering (DLS), and Fourier transform infrared (FTIR) spectroscopy. Furthermore, to interpret the direct images and surface morphologies of the PNIPAM-IL aggregates, we performed field emission scanning electron microscopy (FESEM). The overall specific ranking of ILs in preserving the hydration layer around the PNIPAM aqueous solution was [Emim][Cl] > [Amim][Cl] > [Bmim][Cl] > [Hmim][Cl] > [Bzmim][Cl] > [Dmim][Cl]. Moreover, to investigate the molecular mechanism behind the change in the lower critical solution temperature (LCST) of the polymer in the presence of the ILs, a molecular dynamics (MD) study was performed. The MD simulation has clearly shown the reduction in hydration shell of the polymer after interacting with the ILs at their respective LCST. MD study revealed significant changes in polymer conformation because of IL interactions and strongly supports the experimental observation of polymer phase transition at a temperature lower than typical LCST for all the studied ILs. The driving force for concomitant sharp configurational transition has been attributed to the displacement of water molecules on the polymer surface by the ILs because of their hydrophobic interaction with the polymer.

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Influence of charge density on rheological properties and dehydration dynamics of weakly charged poly(N-isopropylacrylamide) during phase transition

Cited by 11 publications

References 49 publications

Influence of Charged Groups on the Structure of Microgel and Volume Phase Transition by Dielectric Analysis

Influence of Charged Groups on the Structure of Microgel and Volume Phase Transition by Dielectric Analysis

Comparative Study of Different Methods of Synthesis and Their Effect on the Thermomechanical Properties of a Halogenated Epoxy-Based Flame-Retardant Resin

Comprehensive Computational and Experimental Analysis of Biomaterial toward the Behavior of Imidazolium-Based Ionic Liquids: An Interplay between Hydrophilic and Hydrophobic Interactions

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