This paper discusses the solid state and melt nanoscale structure of a series of novel poly(ethylene glycol) (PEG) hybrid di- and triblock copolymers, which contain amphiphilic β-strand peptide sequences. The block copolymers have been prepared via solid-phase synthesis, affording perfectly monodisperse peptide segments with a precisely defined α-amino acid sequence. Attenuated total reflection Fourier transform infrared spectroscopy and X-ray scattering experiments indicate that the self-assembly properties of the peptide sequences are retained upon conjugation to PEG and mediate the formation of an ordered superstructure consisting of alternating PEG layers and peptide domains with an highly organized antiparallel β-sheet structure. The results suggest that combination of biological structural motifs with synthetic polymers may be a versatile strategy for the development of novel self-assembled materials with complex internal structures and the potential to interface with biology.