  Soft materials with a liquid component are an emerging paradigm in materials
design. The incorporation of a liquid phase, such as water, liquid metals, or
complex fluids, into solid materials imparts unique properties and
characteristics that emerge as a result of the dramatically different
properties of the liquid and solid. Especially in recent years, this has led to
the development and study of a range of novel materials with new functional
responses, with applications in topics including soft electronics, soft
robotics, 3D printing, wet granular systems and even in cell biology. Here we
provide a review of solid-liquid composites, broadly defined as a material
system with at least one, phase-separated liquid component, and discuss their
morphology and fabrication approaches, their emergent mechanical properties and
functional response, and the broad range of their applications.
