Shear-Thinning (Pseudoplastic)
Definition
A rheological property where viscosity decreases under applied shear force; the gel ink delivery mechanism depends on this property: the gel liquefies at the ball contact point and re-gels after deposition.
- Property
- Viscosity decreases under applied shear
- Behaviour type
- Pseudoplastic
- Applied to
- Gel pen ink
- Mechanism
- Liquefies at ball contact, re-gels after deposition
Common questions
Why does gel ink need to be shear-thinning to work in a ballpoint mechanism?+
The ink must flow freely enough to coat the rolling ball under the shear of writing motion, then thicken back to a stable gel once deposited on paper so it does not spread, smear, or bleed before drying.
How does this property affect forensic ink examination?+
The re-gelled deposit behaviour influences line edge characteristics and how the ink interacts with paper fibres, features examiners can use alongside chemical composition when comparing or dating gel-ink writing.
Related terms
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