Membrane roughness

A smooth membrane usually fouls less than a rough membrane, especially, when colloidal solutions, such as waters from the pulp and paper industry, are filtered [17]. Process streams might contain fibers or even some solid particles, which can wear... 

Frequently branched, 1.5-3 mm in diameter, rough. Membranous scaly leaves 2-3 mm long, with 3 lobes (rarely 2), apex acute. Fracture showing a triangular rounded pith. 

Fig. 8. Electronmicrograph of a hepatocyte from an adult liver incubated for 30 minutes for glucose-6-phosphatase activity. The deposits of enzyme reaction are evenly distributed throughout the endoplasmic reticulum. N, nucleus nm, nuclear membrane rm, rough membranes of the endoplasmic reticulum sm, smooth membranes m, mitochondria [Courtesy of the Journal of Cell Biology (Leskes et al., 1971).]...

Fortunately, AFM in conjunction with the colloid probe technique offers an alternative means of membrane surface electrical properties characterization. If a colloid probe is approached towards a surface it is possible to quantify the force of interaction. Figure 6.15 shows typical data for a Desal DK membrane, which is one of the least rough membranes [7]. 

The polymerase activity was present in both smooth and rough membranes and the specific activity was approximately the same in both fractions, although the total activity was twice as high in the smooth fraction. The HM fraction had the highest total and specific activity (expressed in relation to protein content). Qualitatively similar results were obtained whether the polymerase activity was assayed with endogenous acceptor or with exogenous substrates. 

With an AFM adhesion force measurement technique, Bowen et al. [42] characterized an interaction force between a colloidal silica probe and a rough membrane surface. It was found that membrane surface roughness significantly reduced electrostatic repulsion between the colloid and the surface, and the valley regions experienced a greater adhesion force. 

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