Responsive membranes for advanced separations

• Performance of responsive membrane modulated by an external stimulus.
• Direct response through target species interacting with specific responsive site.
• Indirect response through mass or mass and heat transfer from bulk medium.
• Field response through interaction with external field without molecular transport.
• Computational methods aid development of more intricate responsive mechanisms.

External physico-chemical switches may modulate the performances of stimuli-responsive membranes. The switches can be turned on and off in three different ways. Sites on a membrane can interact and respond to incoming chemical agents directly. Alternatively a membrane can respond to global environmental changes such as temperature or pressure. These two mechanisms involve mass transport or mass and heat transport. The switches for field-responsive membranes, on the other hand, are external fields, where mass transport or mass and heat transport between the environment and membrane are not required. Guided by advances in modern computational methods, stimuli-responsive membranes represent a new class of advanced membranes that are finding numerous niche applications.