A re-entrant glass transition in colloidal disks with adsorbing polymer

Atmuri, Anand K; Peklaris, George; Kishore, Suhasini; Bhatia, Surita R.

doi:10.1039/c2sm25311a

Cited by 40 publications

(40 citation statements)

References 42 publications

(48 reference statements)

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“…Therefore, the slowing down of the aging dynamics of LAPONITE ® dispersion in presence of multivalent salts and hydrophilic polymer can also be used as a test for the presence of an attractive gel state (10,40). While LAPONITE ® -PEO system has widely been explored in the literature using DLS (43,(45)(46)(47), SANS (40,48,49) and rheology (43,45,46,50), reports on LAPONITE ® -Na 4 P 2 O 7 systems are few in number (40,51). According to a review, a systematic study of the effect of Na 4 P 2 O 7 on low and high concentration of LAPONITE ® dispersion is necessary in order to distinguish the contribution of repulsive and attractive interactions (9).…”

Section: Introductionmentioning

confidence: 99%

Effect of sodium pyrophosphate and understanding microstructure of aqueous LAPONITE^®dispersion using dissolution study

Suman

Mittal

Joshi

2020

J. Phys.: Condens. Matter

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In this work, we investigate physical origin of ergodicity breaking in an aqueous colloidal dispersion of synthetic hectorite clay, LAPONITE ® , at pH 10 by performing dissolution and rheological experiments with monovalent salt and tetrasodium pyrophosphate solution. We also study the effect of interface, nitrogen and paraffin oil on the same. Dissolution experiments carried out for dispersions with both the interfaces show similar results. However, for samples with nitrogen interface, all the effects are observed to get expedited in time compared to paraffin oil interface. When kept in contact with water, 1.5 wt. % and 2.8 wt. % colloidal dispersion at pH 10 swell at small ages, while do not swell at large ages. The solution of tetrasodium pyrophosphate, interestingly, dissolves the entire colloidal dispersion samples with pH 10 irrespective of the concentration of clay. Experiments carried out on colloidal dispersions prepared in water having pH 13 demonstrate no effect of water as well as sodium pyrophosphate solution on the same suggesting a possibility of the presence of negative charge on edge at that pH. We believe that all the behaviors observed for samples at pH 10 can be explained by an attractive gel microstructure formed by edgeto-face contact. Furthermore, the absence of swelling in old colloidal dispersion at pH 10 and dissolution of the same by sodium pyrophosphate solution cannot be explained by merely repulsive interactions. This behavior suggests that attractive interactions originating from edge-to-face contact play an important role in causing ergodicity breaking in the colloidal dispersions at pH 10 at all the ages irrespective of the clay concentration. We further substantiate the presence of fractal network structure formed by interparticle edge-face association using rheological tools and cryo-TEM imaging. We also conduct a comprehensive study of the effect of tetrasodium pyrophosphate in the sol-gel transition of LAPONITE ® dispersion.

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Section: Introductionmentioning

confidence: 99%

Effect of sodium pyrophosphate and understanding microstructure of aqueous LAPONITE^®dispersion using dissolution study

Suman

Mittal

Joshi

2020

J. Phys.: Condens. Matter

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“…3 Therefore, it is not surprising that rheological and phase behaviors of clays have been very active areas of research over past several decades. 1,2,[4][5][6][7][8][9][10][11][12][13][14][15][16][17] In the recent literature synthetic clay mineral called Laponite has received significant attention due to its rich physical behavior and industrial applications. In addition, aqueous Laponite suspension shows time dependence evolution of its microstructure and physical properties that is reminiscent to physical aging in molecular, spin and colloidal glasses.…”

Section: Introductionmentioning

confidence: 99%

Physicochemical Effects in Aging Aqueous Laponite Suspensions

2012

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We study aging behavior of an aqueous suspension of Laponite as a function of concentration of Laponite, concentration of salt, time elapsed since preparation of suspension (idle time), and temperature by carrying extensive rheological and conductivity experiments. We observe that temporal evolution of elastic moduli, which describes structural build-up and aging, shifts to low times for experiments carried out for higher concentration of Laponite, higher concentration of salt, greater temperature, and longer idle time while preserving the curvature of evolution in the solid regime (elastic modulus greater than viscous modulus). Consequently appropriate shifting of evolution of elastic modulus in the solid regime leads to aging time-idle time-salt concentration-Laponite concentration-temperature superposition. The existence of such a superposition suggests the generic nature of microstructure buildup irrespective of mentioned variables in the explored range. The behavior of shift factors needed to obtain the superposition indicate that the energy barrier associated with structural buildup decreases with an increase in idle time and temperature and decreases linearly with an increase in concentration of Laponite and that of salt. The conductivity experiments show that ionic conductivity of the suspension increases with increasing Laponite concentration, salt concentration, temperature, and very importantly the idle time. We also analyze the interparticle interactions using DLVO theory that suggests an increase in idle time, temperature, and salt concentration increases the height of the repulsive energy barrier while it decreases the width of the same when particles approach each other in a parallel fashion. However when particles approach each other in a perpendicular fashion, owing to dissimilar charges on edge and face, the energy barrier for the attractive interaction is expected to decrease with an increase in idle time, temperature, and salt concentration. Analysis of rheological and conductivity experiments suggests a strong influence of attractive interactions on the low energy structures in an aqueous suspension of Laponite.

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“…Because chain lengths are different in each case, the re-arrangement of particles as chains begin to adsorb or cover surfaces would be different, so this may potentially force samples to take different dynamic pathways that eventually lead to similar final states. This qualitative feature of a glassy system melting and reforming into a solid has been observed in a previous work on laponite with PEO of an intermediate molecular weight of 20 kg/mol [41], in laponite with DNA strands [42] and also with sterically stabilized PMMA spheres in a polystyrene medium [43]. In all the experimental studies mentioned above, this transition was found to occur in a polydisperse particle system suspended in a dilute polymer medium where the scaled concentrations (c p /c*) were below 1.…”

Section: Resultsmentioning

confidence: 57%

The effect of particle-scale dynamics on the macroscopic properties of disk-shaped colloid–polymer systems

Kishore

Chen

Ravindra

et al. 2015

Colloids and Surfaces A: Physicochemical and Engineering Aspect

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A re-entrant glass transition in colloidal disks with adsorbing polymer

Cited by 40 publications

References 42 publications

Effect of sodium pyrophosphate and understanding microstructure of aqueous LAPONITE^®dispersion using dissolution study

Effect of sodium pyrophosphate and understanding microstructure of aqueous LAPONITE^®dispersion using dissolution study

Physicochemical Effects in Aging Aqueous Laponite Suspensions

The effect of particle-scale dynamics on the macroscopic properties of disk-shaped colloid–polymer systems

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A re-entrant glass transition in colloidal disks with adsorbing polymer

Cited by 40 publications

References 42 publications

Effect of sodium pyrophosphate and understanding microstructure of aqueous LAPONITE®dispersion using dissolution study

Effect of sodium pyrophosphate and understanding microstructure of aqueous LAPONITE®dispersion using dissolution study

Physicochemical Effects in Aging Aqueous Laponite Suspensions

The effect of particle-scale dynamics on the macroscopic properties of disk-shaped colloid–polymer systems

Contact Info

Product

Resources

About

Effect of sodium pyrophosphate and understanding microstructure of aqueous LAPONITE^®dispersion using dissolution study

Effect of sodium pyrophosphate and understanding microstructure of aqueous LAPONITE^®dispersion using dissolution study