Process for controlling the period characterizing the morphology obtained from a blend of block copolymers and of co(polymers) of one of the blocks

1. A process for controlling the period characterizing the morphology obtained starting from a blend of block copolymers and of (co)polymers of one of the blocks in thin films, comprising the following stages:

a) synthesizing a block copolymer so that the product of the synthesis comprises the said block copolymer and a (co)polymer of one of the blocks;

b) depositing a solution of the blend of the block copolymer and of the (co)polymer on a surface;

c) evaporating the solvent; and

d) annealing;

additionally comprising a purification stage targeted at reducing the amount of (co)polymer.

2. The process according to claim 1 , wherein the process provides thin films having decreased defects of orientation, decreased defects of coordination number, and decreased defects of distance and greater monocrystalline surfaces.

3. The process according to claim 1 , wherein the synthesizing stage is carried out by controlled radical polymerization.

4. The process according to claim 1 , wherein the synthesizing stage is carried out by anionic polymerization.

5. The process according to claim 4 , wherein the anionic polymerization is carried out batchwise for the synthesis of the first block and continuously using a micromixer for the synthesis of the second block.

6. The process according to claim 5 , wherein the proportion of the first active block is adjusted by adjustment of the temperature.

7. The process according to claim 1 , wherein the block copolymer is a diblock copolymer, the ratios by weight of the blocks of which are between 50/50 and 95/5.

8. The process according to claim 1 , wherein the block copolymer/(co)polymer ratios are between 99/1 and 50/50.

9. The process according to claim 1 , wherein the blend of copolymers consists of a blend, on the one hand, of diblock copolymer, one of the blocks of which comprises styrene and the other block of which comprises methyl methacrylate, and, on the other hand, of a (co)polymer which comprises styrene.

10. The process according to claim 9 , wherein the blend of copolymers consists of a blend of PS-b-PMMA diblock copolymer and of PS homopolymer.

11. The process according to claim 10 , wherein the proportion of PS homopolymer is adjusted by a combination of the residence time and of the temperature.

12. The process according to claim 1 , wherein the peak molecular weights of the block copolymer and of the (co)polymer, taken separately, are between 2500 and 300 000 with a dispersity index of between 1.02 and 2.5.

13. The process according to claim 1 , wherein the thickness of the film is greater than 40 nm and less than 400 nm.

14. The process according to claim 1 , wherein the surface is flat and homogeneous.

15. The process according to claim 1 , wherein the surface exhibits guidance structures.

16. The process according to claim 1 , wherein the annealing is carried out by a heat treatment.

17. The process according to claim 1 , wherein the annealing is carried out by a treatment in solvent vapour.

18. The process according to claim 1 , wherein the annealing is carried out by a combination of a heat treatment and of a solvent vapour treatment.