Novel peptidomimetics are provided, which mimic collagen. Molecular structures of interest include for imparting the collagen-mimicking property are each of: Gly-.PSI.[(E)CH.dbd.C]-Xaa-.PSI.[(E)CH.dbd.C]-Yaa; Gly-Xaa-.PSI.[(E)CH.dbd.C]-Yaa; Gly-Xaa-Yaa-.PSI.[(E)CH.dbd.CH]; Gly-.PSI.[(E)CH.dbd.C]-Xaa-.PSI.[(E)CH.dbd.C]-Yaa; Gly-Xaa-.PSI.(E)CH.dbd.C]-Yaa-.PSI.[(E)CH.dbd.CH]; Gly-.PSI.[(E)CH.dbd.C]-Xaa-Yaa-.PSI.[(E)CH.dbd.CH] and Gly-.PSI.[(E)CH.dbd.C]-Xaa-.PSI.[(E)CH.dbd.C]-Yaa-.PSI.[(E)CH.dbd.CH]. Xaa and Yaa each means a natural amino acid, Hyp or Flp. Amide bonds may be altered to create collagen mimics. Preferably a tripeptide polymer comprising at least about 60 (Gly-Pro-Hyp) repeating units and having molecular weight of at least about 40,000 is synthesized as a long, collagen-like material. The new synthetic collagen-like materials may have better resistance to degradation, better mechanical strength and/or better ability to fold than natural collagen.