Quaternary ammonium compounds

An electroneutral compound of general formula (III)

• wherein
• A is a tetravalent linker A-5,
• Q1 to Q4 are identical or different from each other and are selected from the group consisting of R and X,
• wherein R, which may be the same or different at each occurrence, is a C5-C27 aliphatic group, m, m′, m″ and m′″ are 0, k″″ is 0, and X, which may be the same or different at each occurrence, is represented by formula II
• wherein Z1, Z2 and Z3, which may be the same or different, are O, S or NH,
• Y is a divalent C1-C6 aliphatic radical,
• R′, R″ and R′″, which may be the same or different, are hydrogen or a C1 to C4 alkyl group,
• n and n′ are 0 or 1 with the sum of n+n′ being 1 or 2,
• wherein two of substituents Q1 to Q4 are X with each carbon atom of linker A carrying one group X and one group R wherein X and R might be the same or different at each occurrence,
• W is an anion or an anionic group bearing w negative charges and r is the number of substituents Q1 to Q4 which are represented by a group X.