Three-dimensional (3D)-printable stretchable triboelectric nanogenerator fibers
A fabrication process is disclosed for the production of flexible triboelectric nanogenerator (TENG) fiber, which can comprise a copper core surrounded by a silicone cladding. The TENG fibers are fabricated using a coaxial micro-extrusion process that enables 2D and 3D constructs to be fabricated with the fibers via 3D printing on both stationary and moving substrates to form mechanosensors as membranes, meshes, and hollow 3D structures. The mechanosensors can be integrated into wearable items for human activity monitoring, or can be formed on organs for organ monitoring, e.g., monitoring of perfused organs. The mechanosensors can be integrated into facemasks and uses for silent speech recognition, such as words mouthed in the absence of sound production by the speaker. The mechanosensors are self-powered and have high stretchability.
1 . A method for fabricating a flexible triboelectric nanogenerator (TENG) fiber, the method comprising:
with a manifold having an inner barrel and an outer extrusion barrel surrounding the inner barrel, feeding an electrically-conductive (EC) wire or fiber through a first opening formed in a first end of the barrel and out of a second opening formed in a second end of the barrel such that an end portion of the wire or fiber is disposed outside of the second end of the barrel;
anchoring the end portion of the EC wire or fiber to a surface of a substrate;
with the outer extrusion barrel having an elastomeric material disposed therein, subjecting the elastomeric material to pressure conditions to cause the elastomeric material to be extruded through an extrusion nozzle located at an end of the manifold, the extrusion nozzle acting as an extrusion die for aligning EC wire or fiber with the elastomeric material being extruded such that the extruded elastomeric material forms a cladding that surrounds the EC wire or fiber in a substantially coaxial relationship, the extruded EC wire or fiber surrounded by the cladding comprising a flexible triboelectric nanogenerator (TENG) fiber; and
with a motion control system mechanically coupled to the manifold, imparting preselected motion to the manifold as the EC wire or fiber and the surrounding cladding are extruded from the extrusion nozzle to form a two-dimensional (2D) or three-dimensional (3D) construct comprising a plurality of the flexible TENG fibers arranged in a preselected pattern to form a triboelectric mechanosensory.
2 . The method of claim 1 , wherein the electrically-conductive wire or fiber comprises a copper wire or fiber and the elastomeric cladding comprises silicone.
3 . The method of claim 1 , wherein each TENG fiber has an outer diameter that ranges from about 50 micrometers to about 2.5 centimeters.
4 . The method of claim 1 , wherein the method is performed by a 3D printer system in which the manifold and the motion control system are implemented.
5 . The method of claim 1 , wherein the 2D or 3D construct is a 3D construct having a preselected shape.
6 . The method of claim 1 , wherein the 3D construct comprises a triboelectric membrane integrated into a facemask and configured for silent speech detection, and wherein the design of the triboelectric membrane-integrated facemask is such that when the facemask is worn by a user, the triboelectric membrane is positioned over the user's mouth and outputs different electrical signals based on different words mouthed by the user.
7 . The method claim 1 , wherein the 3D construct comprises a triboelectric organ-conforming stretchable mesh disposed on a surface of an organ for monitoring movement of the organ, the triboelectric organ-conforming stretchable mesh generating output electrical signals in accordance with movements of the organ that can be measured to monitor movements of the organ over time.
8 . A method for fabricating a two-dimensional (2D) or three-dimensional (3D) construct, the method comprising:
with a manifold having an inner barrel and an outer extrusion barrel surrounding the inner barrel, feeding an electrically-conductive (EC) wire or fiber through a first opening formed in a first end of the barrel and out of a second opening formed in a second end of the barrel such that an end portion of the wire or fiber is disposed outside of the second end of the barrel;
with the outer extrusion barrel having an elastomeric material disposed therein, subjecting the elastomeric material to pressure conditions to cause the elastomeric material to be extruded through an extrusion nozzle located at an end of the manifold, the extrusion nozzle acting as an extrusion die for aligning EC wire or fiber with the elastomeric material being extruded such that the extruded elastomeric material forms a cladding that surrounds the EC wire or fiber in a substantially coaxial relationship, the extruded EC wire or fiber surrounded by the cladding comprising a flexible triboelectric nanogenerator (TENG) fiber;
with a motion control system mechanically coupled to the manifold, imparting preselected motion to the manifold as the EC wire or fiber and the surrounding cladding are extruded from the extrusion nozzle; and
arranging a plurality of flexible TENG fibers in a preselected pattern to form a triboelectric mechanosensory, the plurality of flexible TENG fibers comprising the flexible TENG fiber.
9 . The method of claim 8 , wherein the electrically-conductive wire or fiber comprises a copper wire or fiber and the elastomeric cladding comprises silicone.
10 . The method of claim 8 , wherein the flexible TENG fiber has an outer diameter that ranges from about 50 micrometers to about 2.5 centimeters.
11 . The method of claim 8 , wherein the flexible TENG fiber has a stretchability that is greater than 600%.
12 . The method of claim 8 , wherein the construct is a 3D construct having a preselected shape.
13 . The method of claim 12 , wherein the 3D construct has a hollow center that is formed by the plurality of flexible TENG fibers being arranged in stack in the preselected pattern.
14 . The method of claim 12 , wherein the 3D construct is formed by the plurality of flexible TENG fibers being arranged in a preselected crossing pattern in which at least some of the plurality of flexible TENG fibers cross over at least some other of the plurality of TENG fibers.
15 . The method of claim 12 , wherein the 3D construct is integrated into a wearable device intended to be worn by a user, the 3D construct outputting electrical signals that can be measured for monitoring movements of the user.
16 . The method of claim 12 , wherein the 3D construct comprises a triboelectric membrane integrated into a facemask and configured for silent speech detection, and wherein the design of the triboelectric membrane-integrated facemask is such that when the facemask is worn by a user, the triboelectric membrane is positioned over the user's mouth and outputs different electrical signals based on different words mouthed by the user.
17 . The method of claim 12 , wherein the 3D construct comprises a triboelectric organ-conforming stretchable mesh disposed on a surface of an organ for monitoring movement of the organ, the triboelectric organ-conforming stretchable mesh generating output electrical signals in accordance with movements of the organ that can be measured to monitor movements of the organ over time.
18 . The method of claim 17 , wherein the triboelectric organ-conforming stretchable mesh is disposed on a kidney for monitoring perfusion-induced edema of the kidney.