Design elements and principles

Engineering

Water transport

Materials science

Chromatography

Systems engineering

Biochemistry

Computer science

Mass transfer

Biochemical engineering

Environmental engineering

Nanotechnology

Membrane

Mass transport

Water flow

Chemistry

Polymer science

Macromolecular Rapid Communications

Many organisms rely on directional water transport schemes for the purpose of water retention and collection. Directional transport of water and other fluids is also technologically relevant, for example to harvest water, in separation processes, packaging solutions, functional clothing, and many other applications. One strategy to promote mass transport along a preferential direction is to create compositionally asymmetric, multi-layered, or compositionally graded architectures. In recent years, the investigation of natural and artificial membranes based on this design has attracted growing interest and allowed researchers to develop a good understanding of how the properties of such membranes can be tailored to meet the demands of particular applications. Here a summary of theoretical works on mass transport through dense asymmetric membranes, comprehensive reviews of biological and artificial membranes featuring this design, and a discussion of applications, remaining questions, and opportunities are provided.

Asymmetric Mass Transport through Dense Heterogeneous Polymer Membranes: Fundamental Principles, Lessons from Nature, and Artificial Systems