Methods for mold release of body-mountable devices including microelectronics
A body-mountable device may include a first polymer layer, a second polymer layer, and a structure that includes a sensor between the first and second polymer layers. Fabricating the body-mountable device may involve providing a respective surface layer on each of one or more molding pieces, forming a first polymer layer, positioning the structure on the first polymer layer and then forming, between molding pieces, the second polymer layer over the structure positioned on the first polymer layer. The surface layer of each molding piece may facilitate release of the polymer layer or fabricated body-mountable device without disruption to the embedded structure.
1. A method for fabricating a body-mountable device, the method comprising:
forming a first polymer layer between a first molding piece and a second molding piece, wherein the first molding piece and the second molding piece combine to form a mold cavity, wherein the first molding piece has a first surface layer, the second molding piece has a second surface layer, and at least one of the first or second surface layers facilitates release of the first polymer layer from at least one of the first or second molding piece, and wherein the first polymer layer defines a first side of the body-mountable device;
releasing the first polymer layer from at least one of the first or second molding piece;
after releasing the first polymer layer from at least one of the first or second molding piece, positioning a structure on the first polymer layer, wherein the structure comprises at least one sensor configured to detect an analyte; and
forming a second polymer layer between the first polymer layer and a third molding piece, such that the structure is at least partially enclosed by the first polymer layer and the second polymer layer, wherein the third molding piece has a third surface layer that facilitates release of the second polymer layer from the third molding piece, and wherein the second polymer layer defines a second side of the body-mountable device.
2. The method of claim 1 , wherein at least one of the first, second or third surface layers comprises a silane.
3. The method of claim 2 , wherein the silane has the structure of formula I:
wherein
A is an atom on the surface of the molding piece; and
R 1 , R 2 and R 3 are each hydrogen, halogen, alkyl, alkenyl, alkoxy, haloalkyl, haloalkoxy, cycloalkyl, phenyl, halophenyl or -A.
4. The method of claim 1 , wherein at least one of the surface layers comprises a water-soluble polymer.
5. The method of claim 4 , wherein the water-soluble polymer comprises a polysaccharide, poly(acrylic acid), dextran, poly(methacrylic acid), poly(acrylamide), poly(ethylene imine), poly(vinyl alcohol), poly(ethylene oxide), poly(ethylene oxide), chitosan, sucrose, or a copolymer thereof.
6. The method of claim 1 , wherein at least one of the surface layers comprises a surfactant.
7. The method of claim 6 , wherein the surfactant is glycerol monostearate, glycerol distearate, glycerol tristearate or a combination thereof.
8. The method of claim 4 , further comprising contacting the at least one of the surface layers with an aqueous solution.
9. The method of claim 6 , further comprising contacting the at least one of the surface layers with an aqueous solution.
10. The method of claim 1 , further comprising forming a channel to the sensor through the second polymer layer.