Porous films obtained from polymer latex

1. A porous material comprising particles of polymer P assembled by a block copolymer, the block copolymer comprising at least one block consisting of a polymer sequence immiscible with the polymer P, and at least two blocks consisting of polymer sequences miscible with the polymer P,

wherein the block copolymer is a triblock copolymer of general formula ABA, in which A represents a block consisting of a polymer sequence miscible with the polymer P, and B represents a block consisting of a polymer sequence immiscible with the polymer P, and

wherein Polymer P comprises a fluoropolymer.

2. The material as claimed in claim 1 , wherein the diameter Dv50 of the particles of polymer P is from 30 to 1000 nm.

3. The material as claimed in claim 1 , wherein:

the block A consists of the same repeating unit(s) as the polymer P; or the block A is a homopolymer or copolymer block, selected from the group consisting of methacrylic polyesters, acrylic polyesters, polyvinylpyrrolidone, polyether glycols, polystyrenes, polylactic acids or polybutadienes; and/or

the block B is a homopolymer or copolymer sequence selected from the group consisting of acrylic or methacrylic polymers, polyvinyl polymers, polystyrene sulfonates, polyether glycols and cellulose-based polymers.

4. The material as claimed in claim 1 , wherein the block A and the block B are acrylic or methacrylic homopolymer or copolymer sequences; the block A being a poly(methyl methacrylate) block; and the block B being a poly(2-(dimethylamino)ethyl methacrylate) block.

5. The material as claimed in claim 1 , having:

a weight content of block copolymer ranging from 1% to 60% and/or

a weight content of polymer P ranging from 40% to 99%.

6. The material as claimed in claim 1 , wherein the block copolymer comprises:

a weight content of blocks consisting of polymer sequences miscible with the polymer P ranging from 10% to 90% and/or

a weight content of blocks consisting of polymer sequences immiscible with the polymer P ranging from 10% to 90%.

7. The material as claimed in claim 1 , wherein the particles of polymer P are linked to one another by said block copolymer.

8. A film comprising at least one layer of material as claimed in claim 1 .

9. The film as claimed in claim 8 , wherein said film is a membrane, or a filtration membrane.

10. The film as claimed in claim 8 , consisting of a coating deposited on a substrate, the substrate being a filtration membrane or a support which is woven or nonwoven.

11. A process for producing the material as claimed in claim 1 , comprising:

providing a suspension of particles of polymer P;

providing said block copolymer;

blending the suspension of particles and of the block copolymer, in the presence of a solvent; and

drying of this blend,

wherein polymer P comprises a fluoropolymer.

12. The process as claimed in claim 11 , wherein the block copolymer is provided in solution in the solvent.

13. A process for producing the material as claimed in claim 1 in latex form, comprising:

providing a solution of polymer P;

providing the block copolymer;

precipitating a blend of polymer P and of block copolymer in water, in the presence of a solvent, resulting in the obtaining of the latex; and

drying of this latex.

14. The process as claimed in claim 11 , further comprising spreading the blend over a surface before the drying step.

15. The process as claimed in claim 11 , wherein the solvent is selected from the group consisting of ethers, ketones, aromatic solvents, alcohols, esters, acetone and tetrahydrofuran.

16. The process as claimed in claim 11 , wherein the material obtained is in the form of a film or membrane and the morphology of the films or membranes obtained consists of an assembly of discrete or coalesced particles.

17. The process as claimed in claim 11 , wherein the material obtained is in the form of a film or membrane and the morphology of the films or membranes obtained consists of a honeycomb structure organized as a bees nest-like structure.

18. The material as claimed in claim 1 , wherein the fluoropolymer comprises at least 75% by weight of units of vinylidene fluoride monomer.

19. The material as claimed in claim 18 , wherein the fluoropolymer comprises vinylidene fluoride homopolymer.

20. The material as claimed in claim 1 , wherein the fluoropolymer comprises a copolymer of vinylidene fluoride with a least one other comonomer selected from the group consisting of chlorotrifluoroethylene (CTFE), hexafluoropropylene (HFP), trifluoroethylene (TrFE), tetrafluoroethylene (TFE) and ethylene.

21. The material as claimed in claim 1 , wherein the fluoropolymer comprises polytetrafluoroethylene (PTFE).