Particle Insight
PI Application notes


The challenge

Here we study the properties of certain cellulose fibers from natural sources. They are sold as thickening agents in a variety of household consumer products such as cosmetics, shampoos, etc. Length, width (thickness) and curl strongly affect the viscosity of the final product.

Applicable measures


Fiber Width
Fiber Length
Fiber Aspect Ratio
Fiber Curl
Range of acceptance

5 - 500 microns
10 - 1000 microns
1.0 - 50.0
0 - 1.00

Typical image

Typical fiber image showing the determined lengths



Fibers of this type are suspended in propanol to prevent rapid dissolution, and then mixed well. Because long fibers tend to align themselves with the direction of flow, lengths longer than the width of the flow cell can be handled.

The image above shows Fiber Length values. The fiber shape model straightens out long thin fibers and reports length, width, and aspect ratio of the straightened rectangle.



fiber data graphs: width and length distibutions

Fiber Width is symmetrical about the mean (16 microns). Fiber Length shows a sharp rise and then a straight dropoff down to 500 microns. The dropoff is almost linear (on the log scale). Fiber length distributions typically do not conform to the usual particle size distribution shapes.

fiber data graphs: AR and Curl distributions

Curl is actually a measure of straightness, numerically -- 1.0 is perfectly straight; lower values mean more curl to the shape. Aspect ratio, the ratio of length to width, shows a mean value of 7.7. The largest aspect ratio seen was about 50.