Sharp Polyelectrolyte Adsorption Cutoff Induced by a Monovalent Salt

Hansupalak, Nanthiya; Santore, Maria M.

doi:10.1021/la0302145

Cited by 59 publications

(88 citation statements)

References 25 publications

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“…Enarsson et al 28 and Saarinen et al 29 also observed this behaviour, when they studied the adsorption of CPAM on cellulose fibers and silica surfaces. A similar trend was established by Hansupalak et al 23 results, who measured the adsorbed amount of DMAEMA on silica, as a function of ionic strength at various pH values. When Rojas 34 et al investigated adsorption of a polymer with a low linear charge density, onto an highly charged mica surface, they noted a monotonic desorption upon the addition of salt.…”

Section: Introductionsupporting

confidence: 88%

“…The practical relevance of polyion adsorption has generated substantial theoretical [6][7][8][9][10][11][12][13][14][15][16][17][18][19] and experimental 6,16,[20][21][22][23][24][25][26][27][28][29][30][31][32] efforts. As mentioned above, surface interactions in polyelectrolyte solutions can often be regulated by increasing or decreasing the addition of simple salt.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Polyelectrolyte Adsorption on Solid Surfaces: Theoretical Predictions and Experimental Measurements

Xie¹,

Nylander²,

Piculell³

et al. 2013

Langmuir

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This work utilizes a combination of theory and experiments, to explore the adsorption of two different cationic polyelectrolytes onto oppositely charged silica surfaces, at pH 9.Both polymers, Poly(diallyldimethylammonium chloride), PDADMAC, and Poly(4-vinyl Nmethylpyridinium iodide), PVNP, are highly charged, and highly soluble in water. Another important aspect is that a silica surface carries a relatively high surface charge density, at this pH level. This means that we have specifically chosen to investigate adsorption under conditions where electrostatics can be expected to dominate the interactions. Of specific focus in this work is the response of the adsorption to the addition of simple salt, i.e. a process * To whom correspondence should be addressed 1 where electrostatics is gradually screened out. Theoretical predictions from a recently developed correlation-corrected classical density functional theory for polyelectrolytes, are evaluated by direct quantitative comparisons with corresponding experimental data, as obtained by ellipsometry measurements. We find that, at low concentrations of simple salt, the adsorption increases with ionic strength, reaching a maximum at intermediate levels (about 200 mM). The adsorption then drops, but retains a finite level even at very high salt concentrations, indicating the presence of non-electrostatic contributions to the adsorption. In the theoretical treatment, the strength of this relatively modest, but otherwise largely unknown, non-electrostatic surface affinity, was estimated by matching predicted and experimental slopes of adsorption curves at high ionic strength. Given these estimates for the non-electrostatic part, experimental adsorption data are essentially captured with quantitative accuracy by the classical density functional theory.

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Section: Introductionsupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Polyelectrolyte Adsorption on Solid Surfaces: Theoretical Predictions and Experimental Measurements

Xie¹,

Nylander²,

Piculell³

et al. 2013

Langmuir

View full text Add to dashboard Cite

show abstract

“…Enarsson et al 20 and Saarinen et al 21 also observed this behaviour, when they studied the adsorption of CPAM on cellulose fibers and silica surfaces. Qualitatively similar findings were noted by Hansupalak et al, 12 who measured the adsorbed amount of DMAEMA on silica, as a function of ionic strength at various pH values. Guzmán et al, 27 on the other hand, observed a monotonically increasing adsorbed amount, as salt was added.…”

Section: Introductionsupporting

confidence: 88%

Theoretical and Experimental Investigations of Polyelectrolyte Adsorption Dependence on Molecular Weight

Xie

Nylander

et al. 2016

Langmuir

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This work focuses on adsorption of polyions onto oppositely charged surfaces, and responses to the addition of simple monovalent salt as well as polyion length (degree of polymerization). We also discuss possible mechanisms underlying observed differences, of the adsorbed amount on silica surfaces at high pH, between seemingly similar polyions. This involves theoretical modelling, utilizing classical polymer density functional theory. We furthermore investigate how long and short chain versions of the polymer adsorb onto carboxymethylated cellulose, carrying a high negative charge. Interestingly enough, comparing results obtained for the two different surfaces, we observe an opposite qualitative response on molecular weight. The large polymer adsorb more strongly at a silica surface, but for cellulose at low salt levels, there are indications that the trend is opposite. Another difference is the very slow * To whom correspondence should be addressed 1 adsorption process observed to cellulose, particularly with short polymers; in fact with short polymers we were sometimes unable to establish any adsorption plateau at all. We speculate that the slow dynamics is due to a gradual diffusion of short polymers into the cellulose matrix.This phenomenon could also explain why short chain polymer seems to adsorb more strongly than long ones, at low salt concentrations, provided that the latter then are too large to enter the cellulose pores. Cellulose swelling at high salt might diminish these differences, leading to more similar adsorbed amounts, or even a lower adsorption for short chains.

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“…When ionic strength increases, a sharp adsorption cutoff for a polyelectrolyte like DMAEMA adsorbing on an oppositely charged surface takes place in the absence of other interactions [187]. The cutoff is sharper if the polymer is weakly charged.…”

Section: Adsorption Of Polymers On Silica Surfacementioning

confidence: 99%