Electrically conducting hydrophilic co-polymers
A process of forming a cross-linked electronically active hydrophilic co-polymer is provided and includes the steps of: a. mixing an intrinsically electronically active material with water to form an intermediate mixture; b. adding at least one hydrophilic monomer, at least one hydrophobic monomer, and at least one cross-linker to the intermediate mixture to form a co-monomer mixture; and c. polymerising the co-monomer mixture.
1. An electrochemical cell, comprising:
a homogenous, isotropic, cross-linked electronically active hydrophilic co-polymer; and
two electrodes with the co-polymer located therebetween,
wherein the co-polymer is formed by a process comprising the steps of:
a. mixing an intrinsically electronically active material with water to form an intermediate mixture;
b. adding at least one hydrophilic monomer, at least one hydrophobic monomer, and at least one cross-linker to the intermediate mixture to form a co-monomer mixture; and
c. polymerising the co-monomer mixture to form the co-polymer,
wherein the co-monomer mixture comprises water in an amount of 5%-50% by weight based on a total weight of the co-monomer mixture,
wherein the co-polymer is self-supporting, and
wherein the electrochemical cell is a supercapacitor.
2. The electrochemical cell according to claim 1 , wherein, in step b, the at least one hydrophilic monomer and the at least one hydrophobic monomer are added to the intermediate mixture prior to the addition of the cross-linker.
3. The electrochemical cell according to claim 1 , wherein, in step b, the at least one hydrophilic monomer is added to the intermediate mixture prior to the addition of the at least one hydrophobic monomer.
4. The electrochemical cell according to claim 1 , wherein the intrinsically electronically active material is selected from polyethylenedioxythiophene: polystyrene sulphonate, polypyrrole, polyaniline, polyacetylene, and a combination thereof.
5. The electrochemical cell according to claim 1 , wherein the at least one hydrophilic monomer is selected from methacrylic acid, 2-hydroxyethyl methacrylate, ethyl acrylate, vinyl pyrrolidone, propenoic acid methyl ester, monomethacryloyloxyethyl phthalate, ammonium sulphatoethyl methacrylate, poly vinyl alcohol, and a combination thereof.
6. The electrochemical cell according to claim 1 , wherein the at least one hydrophilic monomer is selected from vinyl pyrrolidone, hydroxyethyl methacrylate, and a combination thereof.
7. The electrochemical cell according to claim 1 , wherein the at least one hydrophobic monomer is selected from methyl methacrylate, allyl methacrylate, acrylonitrile, methacryloxypropyltris(trimethylsiloxy)silane, 2,2,2-trifluoroethyl methacrylate, and a combination thereof.
8. The electrochemical cell according to claim 1 , wherein the crosslinking agent is allyl methacrylate or ethylene glycol dimethacrylate.
9. The electrochemical cell according to claim 1 , wherein both the cross-linker and the hydrophobic monomer is allyl methacrylate.
10. The electrochemical cell according to claim 1 , wherein the polymerisation step is carried out by thermal, UV, or gamma radiation.
11. The electrochemical cell according to claim 1 , wherein the co-monomer mixture further comprises a polymerisation initiator.
12. The electrochemical cell according to claim 11 , wherein the polymerisation initiator is azobisisobutyronitrile or 2-hydroxy-2-methylpriophenone.
13. The electrochemical cell according to claim 1 , wherein the ratio of the at least one hydrophilic monomer to the at least one hydrophobic monomer is from 20:1 to 1:1 in the co-monomer mixture.
14. The electrochemical cell according to claim 1 , wherein the ratio of the at least one hydrophilic monomer and the at least one hydrophobic monomer: the intrinsically electronically active material is from 30:1 to 2:1 in the co-monomer mixture.
15. The electrochemical cell according to claim 1 , wherein the ratio of the water to the intrinsically electronically active material is from 1:1 to 10:1 in the co-monomer mixture.
16. The electrochemical cell according to claim 1 , wherein the ratio of the water to the intrinsically electronically active material is from 1:1 to 3:1 in the co-monomer mixture.
17. The electrochemical cell according to claim 1 , wherein the process by which the co-polymer is formed further comprises the step of hydrating the co-polymer after the co-monomer mixture is polymerised.
18. The electrochemical cell according to claim 17 , wherein the co-polymer is hydrated such that the hydrated co-polymer comprises at least 10 wt % water, based on a total weight of the hydrated co-polymer.