Absorbent boronate-galactomannan complexes comprising a hydrophobic group are disclosed.

R and R′ both independently represent a hydrophobic group,

P and P′, which may be identical or different, represent a group comprising an amine function optionally bearing a hydrophobic group;

The insulation layer includes a hydrophobic group which repels water and permits superb insulation properties of the ultra-thin layers.

P and P′, which may be identical or different, represent a group comprising an amine function optionally bearing a hydrophobic group;