Methods of modulating interfacial characteristics in a self-assembled, force-transmitting peptide network at a fluid-fluid interface are disclosed. The methods involve exposing a peptide capable of participating in a self-assembled, force-transmitting peptide network, either before or after it interacts with other peptides to form the peptide network to a stimulus that alters the chemical and/or physical properties of the peptide. Use of such methods in applications such as emulsions and foams are also disclosed.