Liquid-based gating mechanism with tunable multiphase selectivity and antifouling behaviour.
Living organisms make extensive use of micro- and nanometre-sized pores as gatekeepers for controlling the movement of fluids, vapours and solids between complex environments. The ability of such pores to coordinate multiphase transport, in a highly selective and subtly triggered fashion and without clogging, has inspired interest in synthetic gated pores for applications ranging from fluid processing to 3D printing and lab-on-chip systems. But although specific gating and transport behaviours have been realized by precisely tailoring pore surface chemistries and pore geometries, a single system capable of controlling complex, selective multiphase transport has remained a distant prospect, and fouling is nearly inevitable. Here we introduce a gating mechanism that uses a capillary-stabilized liquid as a reversible, reconfigurable gate that fills and seals pores in the closed state, and creates a non-fouling, liquid-lined pore in the open state. Theoretical modelling and experiments demonstrate that for each transport substance, the gating threshold-the pressure needed to open the pores-can be rationally tuned over a wide pressure range. This enables us to realize in one system differential response profiles for a variety of liquids and gases, even letting liquids flow through the pore while preventing gas from escaping. These capabilities allow us to dynamically modulate gas-liquid sorting in a microfluidic flow and to separate a three-phase air-water-oil mixture, with the liquid lining ensuring sustained antifouling behaviour. Because the liquid gating strategy enables efficient long-term operation and can be applied to a variety of pore structures and membrane materials, and to micro- as well as macroscale fluid systems, we expect it to prove useful in a wide range of applications.
1] School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA [2] Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, USA.
Xu
X
Hou
School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Yuhang
Y
Hu
School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA.
Alison
A
Grinthal
Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, USA.
Mughees
M
Khan
1] School of Engineering and Applied Sciences, Harvard University, Cambridge, Massachusetts 02138, USA [2] Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, Massachusetts 02138, USA.
Joanna
J
Aizenberg
D000388:Air; D032701:Biomimetics / Q000379:methods; D005740:Gases; D056656:Lab-On-A-Chip Devices; D044085:Microfluidics / Q000379:methods*; D008962:Models, Theoretical; D036103:Nanotechnology / Q000379:methods; D009821:Oils; D054046:Plant Stomata / Q000737:chemistry / Q000378:metabolism; D016062:Porosity; D011312:Pressure; D066330:Printing, Three-Dimensional; D013499:Surface Properties; D014867:Water
D005740:Gases; D009821:Oils; D014867:Water