Drying rate variations of latex dispersions due to salt induced skin formation

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Drying rate variations of latex dispersions due to salt induced skin formation. / Erkselius, Stefan; Wadsö, Lars; Karlsson, Ola.

In: Journal of Colloid and Interface Science, Vol. 317, No. 1, 2008, p. 83-95.

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TY - JOUR

T1 - Drying rate variations of latex dispersions due to salt induced skin formation

AU - Erkselius, Stefan

AU - Wadsö, Lars

AU - Karlsson, Ola

N1 - The information about affiliations in this record was updated in December 2015. The record was previously connected to the following departments: Physical Chemistry 1 (S) (011001006), Polymer and Materials Chemistry (LTH) (011001041), Building Materials (011033004)

PY - 2008

Y1 - 2008

N2 - Film formation from latex dispersions with varying concentrations of sodium dodecylsulfate (SDS) and sodium persulfate (NaPS) was studied with a sorption balance. The drying rate decreased significantly at a critical volume fraction of polymer (pc). Under constant drying conditions the pc varied due to differences in particle stabilization. In SDS containing samples, the droplets wetted larger areas, the film thicknesses decreased and, consequently, the initial evaporation rate was decreased. The decrease in the initial evaporation rate first continued with increasing SDS concentration but leveled off at an apparent critical micelle concentration (CMC). Samples containing NaPS had different types of film formation mechanisms with large variations in pc and the total drying time, which could be explained by differences in the electrostatic stabilization. For dialyzed dispersions containing no NaPS, pc was close to 0.7. In samples with medium high NaPS concentration a skin was formed at the air interface causing an early shift in the evaporation rate, resulting in 0.25<pc<0.7. At high NaPS concentration the particles coagulated and settled giving an apparent increase in pc, i.e., values above 0.7. Deviations from the skin formation behavior predicted by the Routh and Russel (RR) model were observed.

AB - Film formation from latex dispersions with varying concentrations of sodium dodecylsulfate (SDS) and sodium persulfate (NaPS) was studied with a sorption balance. The drying rate decreased significantly at a critical volume fraction of polymer (pc). Under constant drying conditions the pc varied due to differences in particle stabilization. In SDS containing samples, the droplets wetted larger areas, the film thicknesses decreased and, consequently, the initial evaporation rate was decreased. The decrease in the initial evaporation rate first continued with increasing SDS concentration but leveled off at an apparent critical micelle concentration (CMC). Samples containing NaPS had different types of film formation mechanisms with large variations in pc and the total drying time, which could be explained by differences in the electrostatic stabilization. For dialyzed dispersions containing no NaPS, pc was close to 0.7. In samples with medium high NaPS concentration a skin was formed at the air interface causing an early shift in the evaporation rate, resulting in 0.25<pc<0.7. At high NaPS concentration the particles coagulated and settled giving an apparent increase in pc, i.e., values above 0.7. Deviations from the skin formation behavior predicted by the Routh and Russel (RR) model were observed.

U2 - 10.1016/j.jcis.2007.09.041

DO - 10.1016/j.jcis.2007.09.041

M3 - Article

VL - 317

SP - 83

EP - 95

JO - Journal of Colloid and Interface Science

JF - Journal of Colloid and Interface Science

SN - 0021-9797

IS - 1

ER -