The invention provides polymers comprising Formula I: wherein monomer is a repeating unit comprising 2, 3, 4, 5, 6 or 7 carbon atoms and the monomers are linked together through amide or ester bonds; n is about 6 to about 1000; and Linker is an optionally substituted carbon chain that is optionally interrupted by moieties such as oxygen, nitrogen, sulfur, phosphorus, or silicon. Charge is a moiety having a positive or negative charge on a heteroatom, such as nitrogen, oxygen, phosphorus, or sulfur; where the Linker separates the monomer and the Charge by at least six linear atoms. The invention also provides methods of preparing the polymers and the copolymers and methods of using the polymers and copolymers, for example, as drug delivery systems, as membrane penetrating peptides, and as therapeutic agents.