Fig. 1.

Hydrophobic PEI derivatives prepared in the study. (A) Schematic representation of the N-dodecylation and subsequent N-methylation of branched PEIs (see Materials and Methods for details). In the case of 1, the letters a, b, and c correspond to the N,N-dodecyl methyl-polycations prepared from 750-, 25-, and 2-kDa PEIs, respectively. (B) Chemical structures of linear PEI-based polymers synthesized in this work. In the case of 2, the letters a, b, and c correspond to the N,N-dodecyl methyl-polycations prepared from 217-, 21.7-, and 2.17-kDa PEIs, respectively. For 3 through 6, 217-kDa PEI was used.