Viscoelasticity of mixed polyacrylamide solution

Xu, Lina

doi:10.1007/s11771-008-0396-x

Cited by 6 publications

(6 citation statements)

References 9 publications

(3 reference statements)

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“…The measured Young’s moduli increased with increasing indentation speed, except for measurements employing 100 μm/s, which resulted in slightly lower Young’s moduli than the data recorded with 40 μm/s. This was to be expected as it has been reported before that PAAm hydrogels are not purely elastic, but viscoelastic [45]. In principle, an indentation speed of 0.1 μm/s can be assumed as a quasi-static measurement for which viscoelastic behavior can be neglected.…”

Section: Resultsmentioning

confidence: 55%

See 1 more Smart Citation

Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young’s modulus

2019

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Measurements of Young’s moduli are mostly evaluated using strong assumptions, such as sample homogeneity and isotropy. At the same time, descriptions of measurement parameters often lack detailed specifications. Many of these assumptions are, for soft hydrogels especially, not completely valid and the complexity of hydrogel microindentation demands more sophisticated experimental procedures in order to describe their elastic properties more accurately. We created an algorithm that automates indentation data analysis as a basis for the evaluation of large data sets with consideration of the influence of indentation depth on the measured Young’s modulus. The algorithm automatically determines the Young’s modulus in indentation regions where it becomes independent of the indentation depth and furthermore minimizes the error from fitting an elastic model to the data. This approach is independent of the chosen elastic fitting model and indentation device. With this, we are able to evaluate large amounts of indentation curves recorded on many different sample positions and can therefore apply statistical methods to overcome deviations due to sample inhomogeneities. To prove the applicability of our algorithm, we carried out a systematic analysis of how the indentation speed, indenter size and sample thickness affect the determination of Young’s modulus from atomic force microscope (AFM) indentation curves on polyacrylamide (PAAm) samples. We chose the Hertz model as the elastic fitting model for this proof of principle of our algorithm and found that all of these parameters influence the measured Young’s moduli to a certain extent. Hence, it is essential to clearly state the experimental parameters used in microindentation experiments to ensure reproducibility and comparability of data.

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Section: Resultsmentioning

confidence: 55%

“…The AFM measurements result in higher Young’s moduli for higher indentation speeds, except for 100 μm/s. The dependence of the Young’s modulus on the indentation speed is probably due to PAAm being viscoelastic [45]. Viscoelastic properties can be neglected on longer timescales [3] (i.e.…”

Section: Resultsmentioning

confidence: 99%

Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young’s modulus

2019

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“…Corresponding to these actions, the viscoelasticity is described in terms of viscosity, storage modulus and loss modulus. [22] …”

Section: Rheological Propertiesmentioning

confidence: 99%

Physicochemical and Rheological Properties of Novel Magnesium Salt-Polyacrylamide Composite Polymers

Lee

Khan

Morad

et al. 2012

Journal of Dispersion Science and Technology

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Two series of novel inorganic-organic composite polymers have been prepared through physical blending of magnesium chloride and magnesium hydroxide respectively with polyacrylamide aqueous solution. The physicochemical properties of the magnesium salt-polyacrylamide composite polymers were tuned by varying the ratio between the magnesium salt (e.g., magnesium chloride and magnesium hydroxide) and polyacrylamide. Characterizations of magnesium salt-polyacrylamide composite polymers were carried out via FTIR and TEM. Parameters such as solution conductivity and viscosity were also taken into account to characterize the physicochemical properties of the composite polymer aqueous solutions. Magnesium chloridepolyacrylamide (MCPAM) composite polymer aqueous solutions have a higher conductivity compared to magnesium hydroxide-polyacrylamide (MHPAM) composite polymer aqueous solutions. The viscosities of the MHPAM composite polymer aqueous solutions were found higher than MCPAM composite polymer aqueous solutions. The rheological properties of the composite polymer aqueous solutions were investigated using steady-state flow and oscillatory frequency sweep within the linear viscoelastic region. Shear-thinning effect was observed for both composite polymer systems when the shear rate increases. In oscillatory frequency sweep tests, both composite polymer systems show that the viscoelastic behaviors depend strongly on the magnesium salt concentrations. Viscous behavior was found to be dominant for both composite polymer systems.

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“…PAM is a water-soluble linear polymer. PAM and its derivatives have different applications in many areas including agricultural, water treatment, medical, and petroleum industries [ 28 , 29 ]. PAM differs from PVP because it contains not only atoms playing the role of proton-acceptors, but also atoms acting as proton-donors.…”

Section: Introductionmentioning

confidence: 99%

Molecular Dynamics Simulation of Polyacrylamide Adsorption on Cellulose Nanocrystals

et al. 2020

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Classical molecular dynamics simulations of polyacrylamide (PAM) adsorption on cellulose nanocrystals (CNC) in a vacuum and a water environment are carried out to interpret the mechanism of the polymer interactions with CNC. The structural behavior of PAM is studied in terms of the radius of gyration, atom–atom radial distribution functions, and number of hydrogen bonds. The structural and dynamical characteristics of the polymer adsorption are investigated. It is established that in water the polymer macromolecules are mainly adsorbed in the form of a coil onto the CNC facets. It is found out that water and PAM sorption on CNC is a competitive process, and water weakens the interaction between the polymer and CNC.

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Viscoelasticity of mixed polyacrylamide solution

Cited by 6 publications

References 9 publications

Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young’s modulus

Automated analysis of soft hydrogel microindentation: Impact of various indentation parameters on the measurement of Young’s modulus

Physicochemical and Rheological Properties of Novel Magnesium Salt-Polyacrylamide Composite Polymers

Molecular Dynamics Simulation of Polyacrylamide Adsorption on Cellulose Nanocrystals

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