Self-organized films from cellulose I Nanofibrils using the layer-by-layer technique.
The possibility of forming self-organized films using only charge-stabilized dispersions of cellulose I nanofibrils with opposite charges is presented, that is, the multilayers were composed solely of anionically and cationically modified microfibrillated cellulose (MFC) with a low degree of substitution. The build-up behavior and the properties of the layer-by-layer (LbL)-constructed films were studied using a quartz crystal microbalance with dissipation (QCM-D) and stagnation point adsorption reflectometry (SPAR). The adsorption behavior of cationic/anionic MFC was compared with that of polyethyleneimine (PEI)/anionic MFC. The water contents of five bilayers of cationic/anionic MFC and PEI/anionic MFC were approximately 70 and 50%, respectively. The MFC surface coverage was studied by atomic force microscopy (AFM) measurements, which clearly showed a more dense fibrillar structure in the five bilayer PEI/anionic MFC than in the five bilayer cationic/anionic MFC. The forces between the cellulose-based multilayers were examined using the AFM colloidal probe technique. The forces on approach were characterized by a combination of electrostatic and steric repulsion. The wet adhesive forces were very long-range and were characterized by multiple adhesive events. Surfaces covered by PEI/anionic MFC multilayers required more energy to be separated than surfaces covered by cationic/anionic MFC multilayers.
Aulin
Christian
C
BIM Kemi AB, Box 3102, SE-443 03 Stenkullen, Sweden, Department of Fibre and Polymer Technology, School of Chemical Science and Engineering, The Royal Institute of Technology, SE-100 44 Stockholm, Sweden, and Innventia AB, Box 5604, SE-114 86 Stockholm, Sweden. caulin@polymer.kth.se
Johansson
Erik
E
Wågberg
Lars
L
Lindström
Tom
T
D002482:Cellulose / Q000737:chemistry*; D003460:Crystallization; D018625:Microscopy, Atomic Force; D053758:Nanoparticles / Q000737:chemistry*; D056951:Photoelectron Spectroscopy; D011094:Polyethyleneimine / Q000737:chemistry*; D011791:Quartz / Q000737:chemistry*; D013499:Surface Properties; D014867:Water / Q000737:chemistry
D014867:Water; D011791:Quartz; D011094:Polyethyleneimine; D002482:Cellulose