AVS 56th International Symposium & Exhibition
    Inkjet Technology: Printing, Materials Processing, and Microfluidics Fundamentals Topical Conference Wednesday Sessions
       Session IJ+MN+TF-WeA

Paper IJ+MN+TF-WeA10
Controlling the Evaporation and Material Deposition Process of Printed Drops by Systematic Substrate Modification

Wednesday, November 11, 2009, 5:00 pm, Room B3

Session: Inkjet Printing Technology: Advances and Challenges
Presenter: V. Bromberg, Binghamton University
Authors: V. Bromberg, Binghamton University
S. Gawande, Binghamton University
T. Singler, Binghamton University
Y. Sun, Binghamton University
Correspondent: Click to Email
The evaporation dynamics of an inkjet-printed drop on a solid surface have been investigated experimentally. An inkjet-printed drop will generally evaporate in two modes – a continuous decrease in contact angle with a constant contact area, followed by a shrinking of the contact area at a constant contact angle. This evaporation process determines the internal flow and final deposition pattern of functional material being carried by the drop. In an effort to better understand this process, fluorescent microscopy was used to visualize the flow of colloidal material inside printed water drops. We have systematically examined the effects of substrate wettability in controlling the flow and deposition dynamics. It has been found that critical wettability values (as determined by the contact angle) exist which delineate the evaporation and deposition process into regimes of significantly different final deposit patterns. These critical values have been explored as functions of particle characteristics (volume fraction, surface functionality, size) and ambient conditions (relative humidity). A theory of particle kinetics within the three-phase contact line region has been proposed to explain the existence of these critical wettability parameters. These parameters have been used to suggest effective techniques for controlling the shape and structure of final deposition for inkjet printing functional material.