Peptide-amphiphile nanofibers are a versatile scaffold for the preparation of self-assembling materials. This study describes twelve derivatives of peptide-amphiphile molecules designed to self-assemble into nanofibers. The scope of amino acid selection and alkyl tail modification was investigated, yielding nanofibers with varying morphology, surface chemistry, and potential bioactivity. The results demonstrate the chemically versatile nature of this supramolecular system and its high potential for manufacturing nanomaterials. Three different modes of self-assembly resulting in nanofibers are described: pH control, divalent ion induction, and concentration. Preprogrammed noncovalent bonds within and between molecules build highly functional and dynamic structures in biology, motivating interest in self-assembly of synthetic systems. Over the past few decades, a substantial amount of literature describing noncovalent self-assembly of nanostructures has accumulated. However, it is still difficult to design supramolecular structures, particularly if we want to start with designed molecules and form objects that measure between nanoscopic and macroscopic dimensions. Developing this ability will take us closer to the broad, bottom-up approach of self-assembly observed in biology. The study explores self-assembly of designed molecules into macromolecular structures of two-dimensional, one-dimensional, and zero-dimensional nature. These self-assembled objects contain between 10^1 and 10^5 molecules and resemble synthetic and biological polymers in molar mass. The interactions that lead to the formation of these structures include chiral dipole-dipole interactions, π-π stacking, hydrogen bonds, nonspecific van der Waals interactions, hydrophobic forces, electrostatic interactions, and repulsive steric forces. All systems studied involved combinations of these forces that counterbalance the enormous translational and rotational entropic cost caused by polymolecular aggregation. The study also explores self-organization at length scales much greater than those of the aggregates themselves, reaching into scales of microns, millimeters, and even centimeters. The search for useful systems in the microscopic and macroscopic regime that take advantage of molecular self-assembly probably will require a combination of top-down and bottom-up approaches such as ours. The study explores the self-assembly of peptide amphiphiles (PA) in water into one-dimensional cylindrical objects, nanometers in diameter but microns in length. These molecules can be used to inscribe biological signals in the self-assembled structure. In this system, PA 4 was chosen for the self-assembling building block to combine the advantages of peptides with those of amphiphiles that are known to self-assemble into sheets, spheres, rods, disks, or channels depending on the shape, charge, and environment. To enhance the physical and chemical robustness of these supramolecular fibers, an intermolecular crosslinking scheme using four consecutive cysteine residues was included in the design. Upon oxidation of the self-assembledPeptide-amphiphile nanofibers are a versatile scaffold for the preparation of self-assembling materials. This study describes twelve derivatives of peptide-amphiphile molecules designed to self-assemble into nanofibers. The scope of amino acid selection and alkyl tail modification was investigated, yielding nanofibers with varying morphology, surface chemistry, and potential bioactivity. The results demonstrate the chemically versatile nature of this supramolecular system and its high potential for manufacturing nanomaterials. Three different modes of self-assembly resulting in nanofibers are described: pH control, divalent ion induction, and concentration. Preprogrammed noncovalent bonds within and between molecules build highly functional and dynamic structures in biology, motivating interest in self-assembly of synthetic systems. Over the past few decades, a substantial amount of literature describing noncovalent self-assembly of nanostructures has accumulated. However, it is still difficult to design supramolecular structures, particularly if we want to start with designed molecules and form objects that measure between nanoscopic and macroscopic dimensions. Developing this ability will take us closer to the broad, bottom-up approach of self-assembly observed in biology. The study explores self-assembly of designed molecules into macromolecular structures of two-dimensional, one-dimensional, and zero-dimensional nature. These self-assembled objects contain between 10^1 and 10^5 molecules and resemble synthetic and biological polymers in molar mass. The interactions that lead to the formation of these structures include chiral dipole-dipole interactions, π-π stacking, hydrogen bonds, nonspecific van der Waals interactions, hydrophobic forces, electrostatic interactions, and repulsive steric forces. All systems studied involved combinations of these forces that counterbalance the enormous translational and rotational entropic cost caused by polymolecular aggregation. The study also explores self-organization at length scales much greater than those of the aggregates themselves, reaching into scales of microns, millimeters, and even centimeters. The search for useful systems in the microscopic and macroscopic regime that take advantage of molecular self-assembly probably will require a combination of top-down and bottom-up approaches such as ours. The study explores the self-assembly of peptide amphiphiles (PA) in water into one-dimensional cylindrical objects, nanometers in diameter but microns in length. These molecules can be used to inscribe biological signals in the self-assembled structure. In this system, PA 4 was chosen for the self-assembling building block to combine the advantages of peptides with those of amphiphiles that are known to self-assemble into sheets, spheres, rods, disks, or channels depending on the shape, charge, and environment. To enhance the physical and chemical robustness of these supramolecular fibers, an intermolecular crosslinking scheme using four consecutive cysteine residues was included in the design. Upon oxidation of the self-assembled