Molecular Weight Effects on the Film Formation of Latex and on Surfactant Distribution and Morphology

Tzitzinou, A; Keddie, Joseph L.; Geurts, JL; Mulder, M.H.V.; Satguru, R.; Treacher, KE

doi:10.1021/bk-2001-0790.ch004

Cited by 6 publications

(7 citation statements)

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“…The fact that the feature can be removed with water is consistent with the hypothesis that it is composed of surfactant. Similar conclusions have been drawn elsewhere. ,, (Recall that 9% of the surfmer was unreacted in M14-S.) The surface of the SLS-S film (Figure d) is much rougher. Larger hill-like features (up to 1 μm across) are observed.…”

Section: Resultssupporting

confidence: 86%

“…During the film formation process or when the latex is cast at high shear rates, surfactants can migrate toward the film interfaces or concentrate in pockets, creating hydrophilic domains that promote film heterogeneity . Both the layer of surfactant at the film's interfaces and the hydrophilic domains within the film affect final film properties, including water sensitivity, adhesion, gloss, and blocking.…”

Section: Introductionmentioning

confidence: 99%

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Distribution of Surfactants near Acrylic Latex Film Surfaces: A Comparison of Conventional and Reactive Surfactants (Surfmers)

et al. 2003

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The use of reactive surfactants is a promising way of avoiding the deleterious effects on film properties caused by the segregation of conventional surfactants. In this work, the distributions of conventional and reactive anionic surfactants in acrylic latex films are compared. Atomic force microscopy was used to examine the surface of the films cast from high solids content acrylic latexes, and Rutherford backscattering spectrometry provided depth profiles of the surfactants. It was proven conclusively that the use of surfmers is an effective way of eliminating unwanted surfactant exudation. The amount of conventional surfactant (sodium lauryl sulfate (SLS)) exuded to the surface increased with the temperature at which the films were annealed (60, 90, and 125 °C), but the migration of the surfmer (sodium tetradecyl maleate) was very minimal and only weakly dependent on temperature. An unexpectedly large amount of conventional surfactant was exuded to the film surface when annealed at 125 °C. This result suggests that its transport to the surface might be facilitated by the enhanced mobility of poly(acrylic acid) shells at temperatures above the polymer's glass transition temperature (ca. 106 °C).

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Section: Resultssupporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Distribution of Surfactants near Acrylic Latex Film Surfaces: A Comparison of Conventional and Reactive Surfactants (Surfmers)

et al. 2003

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“…In aiming to optimize adhesive performance, there can be conflicting requirements for film formation. Although a latex composed of a polymer with a T g greatly lower than the film formation temperature is expected to coalesce at a fast rate and form a better film, this same system might be more likely to develop an excess of surfactant at the surface with a deleterious effect on adhesion. The effects of surfactant are not always unwanted, however.…”

Section: Surfactants In Latex Filmsmentioning

confidence: 99%

Origins and Effects of a Surfactant Excess near the Surface of Waterborne Acrylic Pressure-Sensitive Adhesives

et al. 2002

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An excess of anionic surfactant at the surface of waterborne acrylic pressure-sensitive adhesives (PSAs) is identified through the complementary use of atomic force microscopy and elemental depth profiling with Rutherford backscattering spectroscopy. This surfactant is distributed around the particles at the film surface, where it presumably contributes to the stabilization of the particles against coalescence. This result is not consistent with the prediction of a process model of film formation that a coalesced skin layer should form, owing to the polymer's low zero-shear-rate viscosity (5 × 10 4 Pa s). To investigate the reason for the surface excess, the spatial distribution of water during film formation of the latex PSAs has been determined using magnetic resonance profiling. In the later stages of drying, the water concentration is very low near the surface, and it increases linearly with the depth into the film. The water profiles indicate that the deformation of particles is not accompanied by coalescence but that water-filled capillaries exist at particle boundaries. It is suggested that the transport of surfactant (and water-soluble polymer, ions, and other species) to the surface is driven by the capillary pressure.

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“…For the samples studied here, the surface should be either film-formed latex or silica. There are other possibilities, such as surfactant exudation during film formation, but this should be a relatively small effect compared to the difference in viscoelastic properties between the silica in the polymer. Therefore, phase contrast should distinguish the relatively soft polymer from the harder silica.…”

Section: Methodsmentioning

confidence: 99%

Surface Properties and Structural Collapse of Silica in Matte Water-Based Lacquers

Royall

Donald

2002

Langmuir

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An investigation into the relationship between surface microstructure and optical properties of matte water-based lacquer is presented, and a model describing this relationship in terms of the packing of silica matting agent is tested. This model assumes that, at some critical concentration, the silica structure in the film-formed lacquer is similar to that found in the dry powder. Above this critical concentration, an increase in surface roughness is expected, which is related to the reflectance of the lacquer. The lacquer surface is accessed via environmental scanning electron microscopy and atomic force microscopy, and the results are related to the model described and the reflectance measured. The reflectance is found to be inversely related to the surface roughness. The prediction for increase in surface roughness above the critical silica concentration is shown to be valid for robust precipitated silicas with large (10 μm) aggregate particles. Smaller 2 μm aggregate particles show a much reduced surface roughness. A difference in behavior is seen between fumed and precipitated silicas. Fumed silica undergoes total structural collapse at high silica concentration, with a limited quantity of silica around the surface. With precipitated silica, the collapse is much less complete, and more silica is present near the surface at high silica concentrations.

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Molecular Weight Effects on the Film Formation of Latex and on Surfactant Distribution and Morphology

Cited by 6 publications

References 0 publications

Distribution of Surfactants near Acrylic Latex Film Surfaces: A Comparison of Conventional and Reactive Surfactants (Surfmers)

Distribution of Surfactants near Acrylic Latex Film Surfaces: A Comparison of Conventional and Reactive Surfactants (Surfmers)

Origins and Effects of a Surfactant Excess near the Surface of Waterborne Acrylic Pressure-Sensitive Adhesives

Surface Properties and Structural Collapse of Silica in Matte Water-Based Lacquers

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