Three alkyl-polypeptide (AP) amphiphiles were prepared using ring-opening polymerization of alpha-amino acid N-carboxyanhydride. The polypeptide segment was composed of diethylene-glycol-monomethyl-ether-functionalized poly-L-glutamate (poly-L-EG(2)Glu). These AP amphiphiles can spontaneously self-assemble into transparent hydrogels in water. These hydrogels showed shear thinning properties, and their strength can be modulated by hydrophobic alkyl tails. CryoTEM and AFM characterizations suggested that these hydrogels were formed by nanoribbons arising from intermolecular interactions between nonionic poly-L-EG(2)Glu segments.