  Nature is remarkably adept at using interfaces to build structures,
encapsulate reagents, and regulate biological processes. Inspired by Nature, we
describe flexible polymer-based ribbons, termed "mesoscale polymers" (MSPs), to
modulate interfacial interactions with liquid droplets. This produces
unprecedented hybrid assemblies in the forms of flagellum-like structures and
MSP-wrapped droplets. Successful preparation of these hybrid structures hinges
on interfacial interactions and tailored MSP compositions, such as MSPs with
domains possessing distinctly different affinity for fluid-fluid interfaces as
well as mechanical properties. In situ measurements of MSP-droplet interactions
confirm that MSPs possess a negligible bending stiffness, allowing interfacial
energy to drive mesoscale assembly. By exploiting these interfacial driving
forces, mesoscale polymers are demonstrated as a powerful platform that
underpins the preparation of sophisticated hybrid structures in fluids.
