The anchoring effect and cooperative interactions in 5CB/CNC molecular films

Abstract

ABSTRACT The advances in nanotechnology allow for the creation of hybrid materials (HMs) composed of LCs (LC) and cellulose nanocrystals (CNC). Cellulose is a natural polymer whose structural properties are used for designing new LC composite materials. The properties of CNC strongly depend on the origin and technological processes used. The LCs are materials displaying different structural properties in function of temperature or concentration that find applications mainly in electronics. The combination of LC and CNC results in enhanced properties, like an extended temperature range of mesophases, higher stability and mechanical strength of LC films. The CNC obtained through transition metal catalysed oxidative process allows obtaining hydroxyl groups active for interactions with LC molecules. By synergic combination and cooperative interaction between components, we have stabilised the 5CB molecules at the air-water interface by the anchoring effect, creating stable and compressible 5CB/CNC molecular films. The π-A isotherms, compressibility modules, Gibbs free energy of spreading, lift-of area, collapse pressure and surface pressure increment for investigated systems at different stages of the formation process are determined. We have demonstrated that creating a hybrid 5CB/CNC Langmuir film is a two-stage process. Obtained films display enhanced stability, strength and ability to form multilayers.