Rheological Behavior of Fugitive Organic Inks for Direct-Write Assembly

• Main Authors: Therriault Daniel, White Scott R., Lewis Jennifer A.
• Format: Article
• Language: English
• Published: De Gruyter 2007-02-01
• Series: Applied Rheology
• Subjects: direct-write; viscoelastic material; organic ink; structural behavior; microfabrication
• Online Access: https://doi.org/10.1515/arh-2007-0001

The rheological behavior of a fugitive organic ink tailored for direct-write assembly of 3D microfluidic devices is investigated. Rheological experiments are carried out to probe the shear storage and loss moduli as well as the complex viscosity as a function of varying temperature, frequency and stress amplitude. Master curves of these functions are assembled using time-temperature superposition. The fugitive ink, comprised of two organic phases, possesses an equilibrium shear elastic modulus nearly two orders of magnitude higher than that of a commercial reference ink at room temperature and a peak in the relaxation spectrum nearly six orders of magnitude longer in time scale. The self-supporting nature of extruded ink filaments is characterized by direct video imaging. Comparison of the experimentally observed behavior to numerical predictions based on Euler-Bernoulli viscoelastic beam analysis yield excellent agreement for slender filaments.