The present invention relates generally to compositions comprising polyelectrolytes complexes (PECs) of anionic and cationic biopolymers capable of forming barriers on fiber based materials. Also disclosed is a fibre based material with a barrier coating against oil and water, wherein the material is provided with a barrier from at least two layers formed from at least one composition comprising a polyelectrolyte complex (PEC) of a cationic biopolymer and an anionic biopolymer, The two layers result in improvements in both oil resistance and water resistance compared to the same material provided with a single layer of said at least one composition.

An aqueous polyelectrolyte (PEC) composition for application to a fibre based material for use in obtaining a barrier coating resistant to oil and water, comprises from 0.1 to 20% (w/w) of carboxymethyl cellulose (CMC) and from 0.1 to 20% of cationic starch (CS), providing PECs with a charge ratio of 1; from 1 to 20% (w/w) of a plasticizer; and from 1 to 15% (w/w) of a pH adjusting agent selected from an acid, a buffering system and a base.

An aqueous polyelectrolyte (PEC) composition for application to a fibre based material for use in obtaining a barrier coating resistant to oil and water, comprises from 0.1 to 20% (w/w) of carboxymethyl cellulose (CMC) and from 0.1 to 20% of cationic starch (CS), providing PECs with a charge ratio of 1; from 1 to 20% (w/w) of a plasticizer; and from 1 to 15% (w/w) of a pH adjusting agent selected from an acid, a buffering system and a base.

The present invention relates to a sheet material having desiccant properties, comprising a base material and a hygroscopic material. The invention also relates to a pack comprising the sheet material, which may be used to hold a consumable for use in a non-combustible aerosol provision system. Methods of preparing the sheet material and uses thereof are also provided.