Methods of making ion-conductive polymer films for electrochromic devices
Methods and materials to fabricate electrochromic including electrochemical devices are disclosed. In particular, emphasis is placed on the composition, fabrication and incorporation of electrolytic sheets in these devices. Composition, fabrication and incorporation of redox layers and sealants suitable for these devices are also disclosed. Incorporation of EC devices in insulated glass system (IGU) windows is also disclosed.
1. A method of making an ion-conductive thermoplastic polymer film for an electrochromic device, wherein the method comprises:
(a) mixing one or more monomers capable of forming a thermoplastic polymer, a plasticizer, a salt which is soluble in the plasticizer, a UV stabilizer, and a polymer-forming catalyst to form a mixture;
(b) polymerizing the mixture to obtain a formulation containing a thermoplastic polymer;
(c) pelletizing said formulation containing a thermoplastic polymer to form pellets;
(d) extruding or casting the pellets to form said ion-conductive thermoplastic polymer film.
2. The method of claim 1 , wherein at least one of the salt, the UV stabilizer and the polymer-forming catalyst is dissolved in at least one of the plasticizer and a monomer prior to its mixing with other ingredients.
3. The method of claim 1 , wherein the polymerization reaction is selected from condensation and addition.
4. The method of claim 1 , wherein more than one plasticizer, polymer-forming catalyst, and UV stabilizer is included in the mixture.
5. The method of claim 1 , wherein the formulation may further contain at least one thermal stabilizer, colorant, processing aid, adhesion promotion agent, non-electronically conductive nanoparticle, or combination thereof.
6. The method of claim 1 , wherein the thermoplastic polymer formed after polymerizing in step (b) is a homopolymer, random copolymer, block copolymer, or a graft polymer.
7. The method of claim 1 , wherein more than one monomer is used, and all monomers are added prior to the start of the polymerization reaction or some monomers are added at different stages of the polymerization step.
8. The method of claim 1 , wherein the polymer is selected from a fluoropolymer, polyurethane, polyvinyl butyral, acrylic, polyester, polyurea, polycarbonate, polyvinyl acetate, or a combination thereof.
9. The method of claim 1 , wherein the plasticizer content is between 20 to 80% by weight of the total weight of the polymer and the plasticizer.
10. The method in claim 1 , wherein the salt content is between 0.05 to 2 M based on the plasticizer content.
11. The method as in claim 1 , wherein the UV stabilizer is present in a concentration of 0.1 to 10% by weight of the thermoplastic polymer film.
12. The method of claim 1 , wherein the mixture prior to polymerization may contain at least one additional monomer which does not participate in the formation of the thermoplastic polymer, and which is polymerized after the thermoplastic polymer film has been formed.
13. The method of claim 12 , further comprising polymerizing the additional monomer by irradiating the thermoplastic polymer film after step (d).
14. The method of claim 1 , wherein the ion-conductive thermoplastic film is in contact on a first side with a first redox layer and in contact on a second side with a second redox layer such that the ion-conductive thermoplastic film exchanges ions with the first and second redox layers.
15. The method of claim 14 , wherein the ion-conductive thermoplastic film is constructed out of transparent polymers.
16. The method of claim 14 , wherein the ion-conductive thermoplastic film has a thickness that is between 100 microns and 1000 microns.
17. The method of claim 1 , wherein the thermoplastic polymer is a thermoplastic polyurethane made by reacting a diisocyanate monomer with a first polyol monomer and a second polyol monomer, each of the first and second polyols having a functionality of two, wherein the first polyol has a short molecular weight and wherein the second polyol has a longer chain with a higher molecular weight than the first polyol.
18. The method of claim 17 , wherein the second polyol has a molecular weight between 600 and 3500.
19. The method of claim 17 , wherein the first and the second polyols are polyester-polyols or polycarbonate-polyols.
20. A method of making an ion-conductive thermoplastic polymer film for an electrochromic device, wherein the method comprises:
(a) mixing one or more monomers capable of forming a thermoplastic polymer, a plasticizer, a salt which is soluble in the plasticizer, a UV stabilizer, and a polymer-forming catalyst to form a liquid mixture;
(c) polymerizing the liquid mixture to obtain a solid formulation which is thermoplastic;
(c) pelletizing said solid formulation to form pellets;
(d) extruding or casting the pellets to form said ion-conductive thermoplastic polymer film.
21. A method of making an ion-conductive thermoplastic polymer film for an electrochromic device, wherein the method comprises:
(a) mixing one or more monomers capable of forming a thermoplastic polymer, a plasticizer, a salt which is soluble in the plasticizer, a UV stabilizer, and a polymer-forming catalyst to form a liquid mixture;
(b) polymerizing the liquid mixture to obtain a solid formulation which is thermoplastic;
(c) extruding or casting the said solid formulation to form said ion-conductive thermoplastic polymer film.