The hydrogen-bonded films were prepared via layer-by-layer assembly of poly(vinylpyrrolidone) (PVPON

hydrogen bond acceptors) and poly(acrylic acid) (PAA

hydrogen bond donors).UV-Visible spectra

FTIR spectra and AFM were used to investigate the hydrogen bond detachment and the film disintegration in acidic solvents:formic acid

trifluoroacetic acid

phosphoric acid and poly(phosphoric acid).The dissolution rate of the PVPON/PAA thin film in different acids was queued as:trifluoroacetic acid phosphoric acid formic acid.The experimental results indicated that the mechanism of hydrogen bond detachment was not the same in different acids.Trifluoroacetic acid shows strong interaction with PAA

which induces the detachment of hydrogen bonds between PVPON and PAA

and thus the PVPON/PAA film dissolves.However

phosphoric acid or poly(phosphoric acid) has strong interaction with PVPON

which makes hydrogen bonds between PVPON and PAA break and the thin film decomposes.Poly(phosphoric acid) has more hydrogen bonding donor groups than phosphoric acid

and hence the interaction between poly(phosphoric acid) and PVPON exhibits an synergetic effect.Formic acid and PAA both belong to the family of carboxylic acids.It is very hard for formic acid to replace PAA to form hydrogen bond with PVPON

and hence the film dissolution rate in formic acid is very low.