Transp Porous Med DOI 10.1007/s11242-014-0293-8 Inﬂuence on Pore Structure of Micro/Nanoﬁbrillar Cellulose in Pigmented Coating Formulations Katarina Dimic-Misic · Cathy Ridgway · Thaddeus Maloney · Jouni Paltakari · Patrick Gane Received: 13 September 2013 / Accepted: 10 February 2014 © Springer Science+Business Media Dordrecht 2014 Abstract Nano and microﬁbrillated cellulose (NFC and MFC, respectively, collectively termed MNFC) is known to interact strongly with water, related to its high polarity and surface area. The swelling behaviour acts to form a gel with high water retention properties. The observation that nanocellulose could possibly be used in paper or other coating formulations, as a co-binder, for example, raises a question about the possible effects it could have on coating pore structure. In this study, we analyse the pore structure of pigmented coatings, liquid absorption and permeability, in respect to the inﬂuence of partially substituting traditional co-binder carboxymethyl cellulose with MNFC. The contrast between polar water and non- polar liquid, such as alkane, is used to probe the water interactive and extractable in-coating (internal) gel-formation properties of the nanocellulosic materials. These contrasting liquids are important in many processes, such as offset printing, but also in respect to exposure of coatings in general to environmental factors in application. Results show that permeability to liquid water is dramatically reduced when nanocellulosic material is present, though water can permeate by diffusion through the nanocellulose gel network. Long timescale exposure to water during absorption leads to extraction of any soluble salts remaining after the chemical treatment of the ﬁbrillar material during production. Inert alkane, on the other hand, can absorb and permeate freely without interactive hindrance from the nanocellulose, with no extractive effect. Such a construct could in principle be considered for use as an oil-water differential membrane or for slow release concepts in aqueous systems by loading soluble deliverable materials within the nanocellulosic gel. Keywords NFC · MFC · Coating porosity · Imbibition in porous structures · Water/oil absorption · Controlled release K. Dimic-Misic (B ) · T. Maloney · J. Paltakari · P. Gane Department of Forest Products Technology, School of Chemical Technology, Aalto University, 00076 Aalto, Helsinki, Finland e-mail: katarina.dimic.misic@aalto.ﬁ C. Ridgway · P. Gane Omya International AG, 4665 Oftringen, Switzerland 123