The present invention provides an amphiphilic linear peptide and/or peptoid as well as a hy-drogel that includes the amphiphilic linear peptide/peptoid. The amphiphilic linear pep-tide/peptoid is capable of forming, a hydrogel. These peptides/peptoids include short amphi-philic sequences with a hydrophobic portion of aliphatic amino acids and at least one acidic, neutral, or basic polar amino acid. The amphiphilic linear peptide/peptoid is build up of non repetitive aliphatic amino acids, which may be in the L- or D-form. A plurality of such pep-tides/peptoids assembles to supramolecular helical fibers and forms peptide hydrogels after assembly: A corresponding hydrogel is formed in aqueous solutions at physiological pH and is thus useful for inter alia cell culture, tissue engineering, and drug release. Such hydrogels which are rigid, biocompatible and entrapping up to 99.9% of water are also well suited for applications utilizing electronic devices.