The PhD proposal below concerns the development of innovative solutions to obtain barrier for flexible cellulosic substrate. The main scientific challenges are: formulation of barrier solutions or suspensions or emulsions, crosslinking or supramolecular interactions characterization, coating process and in-operando thermal treatment, barrier properties to liquid and gas, recyclability evaluation of fibre based materials. A focus on the packaging applications and ensued properties will be done to propose innovative but applied solutions and to realize demonstrators.