Micron-resolution soft stretchable strain and pressure sensor

A method for measuring strain, pressure, deformation, stress, displacement, or a combination thereof using a stretchable strain sensor (1), the method comprising:

• a. providing the stretchable strain sensor (1), the sensor comprising:
• a first soft polymer layer (100);
• a wrinkled conductive layer (200) disposed on the first soft polymer layer (100);
• and
• a second soft polymer layer (300) disposed on the wrinkled conductive layer (200);
• wherein strain, pressure, deformation, stress, displacement, or a combination thereof applied to the strain sensor (1) causes the wrinkled conductive layer (200) to stretch and crack, creating resistance in the wrinkled conductive layer (200) and sending a signal based on the resistance;
• wherein the first and second soft polymer layers have an elastic modulus ranging from about 225 to 275 kPa;
• b. applying strain, pressure, deformation, stress, displacement, or a combination thereof to the strain sensor (1);
• c. stretching and cracking, by the wrinkled conductive layer (200), in response to the strain, pressure, deformation, stress, displacement, or combination thereof of the strain sensor (1);
• d. generating, by the wrinkled conductive layer (200), resistance as a result of stretching and cracking;
• and
• e. sending a signal based on the resistance generated by the wrinkled conductive layer (200).

A method for fabricating a stretchable strain sensor (1) into a microfluidic channel to allow measurement of strain, pressure, deformation, stress, displacement, or a combination thereof in the microfluidic channel, the method comprising:

• a. applying heat to a conductive material layer to cause shrinkage in order to produce a wrinkled conductive layer (200);
• b. preparing and tuning a polymer composition to have an elastic modulus to 225 to 275 kPa, thereby producing a soft polymer composition
• c. applying a first layer (100) comprising the soft polymer composition to a first side of the wrinkled conductive layer (200);
• and
• d. applying a second layer (300) comprising the soft polymer composition to a second side of the wrinkled conductive layer (200) such that the wrinkled conductive layer (200) is disposed between the first soft polymer layer (100) and the second soft polymer layer (300).