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Vaterite is a crystal polymorph of calcium carbonate that is widely used in various industries, but rarely occurs in nature. This article presents an effective method for application of vaterite-type calcium carbonate as a coating pigment for ink jet paper instead of silica. Vaterite was prepared by mixing and agitating K 2 CO 3 and CaCl 2 solutions with an ultrasonic homogenizer. The vaterite crystal stability was examined to achieve vaterite properties appropriate for ink jet application. A high pH reduced transformation from vaterite to calcite because of the low solubility constant. Experiments revealed a low water contact angle on our vaterite-coated paper, suggesting high ink jet print quality. Furthermore, although our test calcitecoated and silica-coated samples exhibited bleeding, our vateritecoated samples matched commercial silica-coated samples in quality, probably, because the large hydrophilicity of vaterite promoted quick inward absorption of inks before they could spread laterally on the surface.

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The development of microfluidic paper-based analytical devices is the most promising emerging research globally, due to its main advantage of spontaneous liquid transport.

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This article presents an industrially feasible method to effectively reduce vessel picking tendency by a simple chemical modification of pulp. ECF-bleached eucalyptus kraft pulp was treated with carboxymethyl cellulose (CMC) under specified conditions. The aim was to study the effects on vessel element structure and vessel picking tendency of the laboratory sheets prepared. In addition to the improved strength properties of the sheets, a significant decrease in vessel picking tendency was noted in the laboratory printing test. Whereas refining improved mainly the bonding ability of fibers, CMC treatment effectively enhanced the bonding of vessels as well. Moreover, filmlike structures were formed in the fibrillated areas of the CMC-treated handsheets, and they were concluded to reinforce bonding within the sheet. Also, fragmentation of vessel elements through CMC modification was found to be important and to result in a decreasing picking tendency.