Surfactants cumulative effects

When this non-ionic surfactant is added to a sodium hydroxide solution of pH 12.9, the pH does not change. The dissolution rate is depressed, but increased amounts of the surfactant do not further depress the rate (Hgure 3). An inddental observation can be made from these data. That is, the dissolution rate does decrease somewhat for coated wafers that have been held 4 days at room temperature after prebaking regardless of the medium in whidi they are dissolved. The reason for the rate depression by Triton X-100 is not dear. The formation of an adsorbed layer at the aqueous-polymer interface is likefy. Raising the concentration of surfactant in the bi of the liquid would not necessarily increase the thickness of the adsorbed layer, hence the lack of any cumulative effect. 

The effects of rate-limited solubilization, subsurface layering and flushing solution density on PCE recovery were evaluated in two separate box studies (Box A and Box B). Box A was flushed with 4% Tween 80 alone to serve as the control case, while Box B was flushed with 4% Tween 80 + 5% EtOH to evaluate the effects of cosolvent addition on PCE solubilization, cumulative PCE recovery, and surfactant delivery. Each box was packed with 20-30 mesh Ottawa sand as the background porous medium, with one rectangular layer of F-70 Ottawa sand above two side-by-side rectangular... 

Cumulative (Longer Term) Effects of Repeated Exposure to Surfactants... 412... 

Long-term surfactant damage to the SC lipid extends from the short-term effects resulting in cumulative loss of barrier function and lipid fluidity leading to profound dryness. The results of an assessment... 

The major factor in skin diseases caused by exogenous substances is the repeated and cumulative action on the skin of agents in weak irritant solutions. The repeated exposure to surfactants represents a model for the induction of ICD (Tupker et al. 1989a). During the course of the exposure (patch test applied twice daily for 3 weeks), a progressively damaging clinical effect accompanied by an increase in TEWL (due to a cumulative action of these agents on the skin) is observable. 

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