Simple flow control for microfluidic devices

A microfluidic device comprising:

• a body having a microchannel formed therein and a liquid-pinning trench formed therein;
• and
• an electrode that at least partly overlaps the liquid-pinning trench;
• wherein:
• the microchannel is defined by microchannel walls and defines a flow path for a liquid;
• the liquid-pinning trench is defined by trench walls and has an opening, and a depth of the trench extends transversally to a flow direction imposed to the liquid by the microchannel, in operation;
• the microchannel walls include a bottom wall and a first lateral wall and a second lateral wall, the first lateral wall being arranged on a first side of, and contiguous with, the bottom wall, the second lateral wall being arranged on a second side of, and contiguous with, the bottom wall, whereby the opening of the trench extends across the bottom wall;
• the trench walls comprise a bottom trench wall and opposite sidewalls that are contiguous with and on a respective side of the bottom trench wall;
• and
• one or each of the opposite sidewalls are coated with a hydrophobic material layer.

A microfluidic device comprising:

• a body having a microchannel formed therein and a liquid-pinning trench formed therein;
• and
• an electrode that at least partly overlaps the liquid-pinning trench;
• wherein:
• the microchannel is defined by microchannel walls and defines a flow path for a liquid;
• the liquid-pinning trench is defined by at least one trench wall and has an opening, and a depth of the trench extends transversally to a flow direction imposed to the liquid by the microchannel, in operation;
• the microchannel walls include a bottom wall and a first lateral wall and a second lateral wall, the first lateral wall being arranged on a first side of, and contiguous with, the bottom wall, the second lateral wall being arranged on a second side of, and contiguous with, the bottom wall, whereby the opening of the trench extends across the bottom wall;
• and
• said electrode comprises a metal layer with a self-assembled monolayer of molecules arranged thereon.

A microfluidic device comprising:

• a body having a microchannel formed therein and a first liquid-pinning trench formed therein and a second liquid-pinning trench formed therein;
• a first electrode;
• and
• a second electrode;
• wherein:
• the microchannel is defined by at least one microchannel wall and defines a flow path for a liquid;
• the first liquid-pinning trench is defined by at least one trench wall and has an opening that extends across at least a portion of the at least one microchannel wall, and a depth of the first liquid-pinning trench extends transversally to a flow direction imposed to the liquid by the microchannel, in operation;
• the second liquid-pinning trench is defined by at least one trench wall and has an opening that extends across at least another portion of the at least one microchannel wall, and a depth of the second liquid-pinning trench extends transversally to the flow direction imposed to the liquid by the microchannel, in operation;
• the second electrode is electrically insulated from the first electrode and is configured so as to be contacted by a liquid introduced in the microchannel, in operation;
• and
• the first electrode is formed from a set of first electrode contacts, each contact of the set of first electrode contacts extending so as to at least partly overlap a respective one of the first and second liquid-pinning trenches, wherein the first electrode contacts are connected, so as to form the first electrode as a single, common electrode.