Studies on permeation through polymer latex films, II. Permeation modification by sucrose addition

Steward, Paul A.; Hearn, J.; Wilkinson, M. C.

doi:10.1002/pi.1995.210380102

Cited by 9 publications

(12 citation statements)

References 10 publications

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“…Fine CaCO 3 particles that can be leached with a mild solution of acetic acid have been evaluated by Flanagan et al (2) and water-soluble protein (casein) and other carbohydrate polymers have been evaluated by Flickinger et al (19). Steward et al (20,21) have examined sucrose and soluble polymeric additives. Substances that would remain particulate in the coating mixture without going into solution would give a different structure than those that dissolve in the coating mixture.…”

Section: Figmentioning

confidence: 98%

Microstructure of a Biocatalytic Latex Coating Containing Viable Escherichia coli Cells

Thiagarajan

Huang

Scriven

et al. 1999

Journal of Colloid and Interface Science

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Section: Figmentioning

confidence: 98%

Microstructure of a Biocatalytic Latex Coating Containing Viable Escherichia coli Cells

Thiagarajan

Huang

Scriven

et al. 1999

Journal of Colloid and Interface Science

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“…Beyond this level of sucrose addition (hereafter termed 'C,' (« 25%)), whereas the ^-nitrophenol permeability coefficient increased at a lesser rate, the KC1 permeation rate started to increase with increasing amounts of sucrose. A calculation of the pore radii determined by comparison of the effective K + diffusion coefficients through the film and in free aqueous solution showed that the effective pore radius in the film was tending to plateau at ) 40% sucrose load (37). At a sucrose loading of 40%, the series of three anilines demonstrated permeability coefficients which were greater than those of the sucrose-free Eudragit NE 30 D film, but which were still dependent on the rank order of there solubility in the film.…”

Section: Homentioning

confidence: 99%

“…^Total ** ^Total ~ ^Activated + ^Convecdonal (6) In the case of electrolyte, D Acdvated = 0, and the measured permeability coefficient is effectively the diffusion coefficient. A diffusion coefficient of 1.26xl0" 7 m 2 hr" 1 through the aqueous channels within the polymer compares to a value of ca 4.6X10" 6 m 2 hr" 1 for Na + ions in free aqueous solution.…”

Section: Steward Et Al Polymer Latex Films Containing Leachable Addimentioning

confidence: 99%

Permeation and Morphology in Polymer Latex Films Containing Leachable Additives

Steward¹,

Hearn

Wilkinson³

et al. 1996

ACS Symposium Series

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This paper reviews recent research, performed at The Nottingham Trent University, into the enhancement of the permeability properties of polymer latex films. Both leachate-free model colloid latices, made by surfactant-free emulsion polymerisation, and commercially available latices, containing surfactants and often requiring plasticiser addition to achieve good film formation, have been studied. Water soluble leachable additives such as sucrose, HPMC and a soluble polymer latex, have been employed to deliberately enhance solute permeant flux, and the transport properties of the films are discussed with reference to film morphology. The use of increasing levels of leachable additive allows the solute transport mechanism to be systematically changed from one in which permeation occurs predominantly by solution-diffusion to a mechanism in which convective diffusion predominates and solute permeation tends to become independent of penetrant solubility in the polymer. The results are discussed in terms of the increased hydration of the polymer resulting from additive leaching.Whenever polymer latex films are used as coatings, then their permeabilities to gases, water vapour and solutes are likely to be of significance. In the case of barrier coatings for substrate protection, a minimisation of the flux would often be desirable, but where coatings are used to aid sustained or controlled release of an active ingredient then an ability to modify the flux is needed. In the latter application, water soluble leachates play an important role.This paper utilises free polymer latex films to investigate the transport properties of such films to a range of permeants, and the effects on film permeability of leachable additives ranging from endogenous surfactants, essential plasticisers and molecular sized

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“…Polymer particle coalescence and therefore the permeability can be difficult to control during drying of a coating. During drying the fusion of latex spheres is driven by polymer−water interfacial tension, capillary pressure, layer compression, and interparticle adhesion (9−13). Even after the coating has dried, further reduction in permeability can occur as a function of time, relative humidity, and temperature (12, 13).…”

Section: Introductionmentioning

confidence: 99%

Engineering the Microstructure and Permeability of Thin Multilayer Latex Biocatalytic Coatings Containing E. coli

Lyngberg

Thiagarajan

et al. 2001

Biotechnol. Prog.

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The microstructure and permeability of rehydrated 20-100 microm thick partially coalesced (vinyl-actetate acrylic copolymer) SF091 latex coatings and a 118 microm thick model trilayer biocatalytic coating consisting of two sealant SF091 layers containing a middle layer of viable E. coli HB101 + latex were studied as delaminated films in a diffusion apparatus with KNO(3) as the diffussant. The permeability of the hydrated coatings is due to diffusive transport through the pore space between the partially coalesced SF091 latex particles. Coating microstructure was visualized by fast freeze cryogenic scanning electron microscopy (cryo-SEM). The effective diffusion coefficient of SF091 latex coatings (diffusive permeability/film thickness) was determined as the ratio of the effective diffusivity of KNO(3) to its diffusivity in water (D(eff)/D). Polymer particle coalescence was arrested by two methods to increase coating permeability. The first used glycerol with coating drying at 4 degrees C, near the glass transition temperature (T(g)). The second method used sucrose or trehalose as a filler to arrest coalescence; the filler was then dissolved away. D(eff)/D was measured as a function of film thickness; content of glycerol, sucrose, and trehalose; drying time; and rehydration time. D(eff)/D varied from 3 x 10(-4) for unmodified SF091 coatings to 6.8 x 10(-2) for coatings containing sucrose. D(eff)/D was reduced by the flattening of latex particles against the surface of the solid substrate, as well as by the presence of the colloid stabilizer hydroxyethylcellulose (HEC). When corrected for the flattened particle layer, D(eff)/D of HEC-free coatings was as high as 0.20, which agreed with the value predicted from analysis of cryo-SEM images of the coat surface. D(eff)/D decreased by one-half in approximately 5 days in rehydrated SF091 coatings, indicating that significant wet coalescence occurs after glycerol, sucrose, or trehalose are leached from the films. D(eff)/D of SF091 latex trilayer coatings containing viable E. coli HB101 cells decreased as cell loading was increased from 2.2 x 10(-2) for 64 g dry cell weight per liter of coat volume to 5 x 10(-3) for 151 g DCW/L of coat volume. The reduction in coating permeability with increasing cell loading is predicted by Maxwell's equation for D(eff)/D in periodic composites.

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Studies on permeation through polymer latex films, II. Permeation modification by sucrose addition

Cited by 9 publications

References 10 publications

Microstructure of a Biocatalytic Latex Coating Containing Viable Escherichia coli Cells

Microstructure of a Biocatalytic Latex Coating Containing Viable Escherichia coli Cells

Permeation and Morphology in Polymer Latex Films Containing Leachable Additives

Engineering the Microstructure and Permeability of Thin Multilayer Latex Biocatalytic Coatings Containing E. coli

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