We Claim:
1. A block copolymer comprising:
- at least one block A of formula (I) below:
0""^Q
I.
R2
(!)
in which
p is an integer ranging from 2 to 100,
Ri' is chosen from hydrogen and a methyl group,
RT2 is chosen from Ci to C34 hydrocarbon-based chains,
- at least one block B of formula (II) below:
, z o
I
G (II)
in which
n is an integer ranging from 2 to 40,
R1 is chosen from hydrogen and a methyl group,
Z is chosen from an oxygen atom and a group -NR'- with R' being chosen from a hydrogen
atom and C1 to C12 hydrocarbon-based chains,
G is a C1 to C34 hydrocarbon-based chain substituted with at least one quaternary
ammonium group and optionally one or more hydroxyl groups.
2. The block copolymer as claimed in claim 1, in which:
- block A consists of a chain of structural units derived from an alkyl (meth)acrylate monomer (ma), and
- block B consists of a chain of structural units derived from an alkyl (meth)acrylate or alkyl(meth)acrylamide monomer (mt>), the alkyl radical of which is constituted by a C1 to

C34 hydrocarbon-based chain substituted with at least one quaternary ammonium group and optionally one or more hydroxyl groups.
3. The block copolymer as claimed in claim 2, in which the monomer (ma) is chosen from Ci to C34 alkyl acrylates and C1 to C34 alkyl methacrylates.
4. The block copolymer as claimed in claim 2, in which the alkyl radical of the monomer (mb) is substituted with at least one quaternary ammonium group and one or more hydroxyl groups.
5. The block copolymer as claimed in claim 1, in which the quaternary ammonium group is chosen from pyrrolinium, pyridinium, imidazolium, triazolium, triazinium, oxazolium and isoxazolium quaternary salts.
6. The block copolymer as claimed in claim 1, in which the quaternary ammonium group is chosen from trialkylammonium, guanidinium and iminium quaternary salts.
7. The block copolymer as claimed in claiml, in which block B is represented by one
of the formulae (III) and (IV) below:
R1 R1
\ R2 RB R3
m *HZ 2 O HI t ^O
/ +x- ll+ x-
RS K R7
(III) (IV)
in which
n, Z and R1 are as defined in claim 1,
X" is chosen from hydroxide and halide ions and organic anions, R2 is chosen from C1 to C34 hydrocarbon-based chains, optionally substituted with at least one hydroxyl group,
R3, R4 and R5 are identical or different and chosen independently from C1 to C18 hydrocarbon-based chains, it being understood that the alkyl groups R3, R4 and R5 may contain one or more groups chosen from: a nitrogen atom, an oxygen atom and a carbonyl group and that the groups R3, R4 and R5 may be connected together in pairs to form one or more rings,

R6 and R7 are identical or different and chosen independently from C1 to C18 hydrocarbon-based chains, it being understood that the groups R6 and R7 may contain one or more groups chosen from: a nitrogen atom, an oxygen atom and a carbonyl group and that the groups R6 and R7 may be connected together to form a ring.
8. The block copolymer as claimed in claim 7, in which the group R2 is represented
by one of the formulae (V) and (VI) below:
rJL m x bond with N tj >*
JC ^s%f "y* bond with z
bond with N bond with 2 ,/^V
OH R9 OH
(V) (VI)
in which
Rs is chosen from C1 to C32 hydrocarbon-based chains, Rg is chosen from hydrogen and C1 to C6 alkyl groups.
9. The block copolymer as claimed in claim 7, in which block B of formula (III), (IV),
(V) or (VI) is derived from a monomer (mt>) obtained by the reaction:
- of a tertiary amine of formula NR3R4R5 or R6N=Rz in which R3, R4, R5, R6 and R7 are as , defined in claim 7, and
- of a (meth)acrylate or (meth)acrylamide intermediate monomer (mi) of formula (VII) below:
y z 0
o
R9
(VII) in which Z, R1, Rs and R9 are as defined in claims 1, 7 and 8.
10. The block copolymer as claimed in claim 7, in which block B is obtained by post-
functionalization of an intermediate polymer Pi comprising at least one block P of formula
(VIII) below:

R1
n
R9
(VIII) in which
n, Z, Ri, Rs and R9 are as defined in claims 1, 7 and 8,
and in which said post-functionalization corresponds to the reaction of said intermediate polymer P/'with a tertiary amine NR3R4R5 or R6N=R7 in which R3, RA, RS, R6 and R7 are as defined in claim 7.
11. The block copolymer as claimed in claim 10, in which the intermediate polymer P/ also comprises at least one block A as defined in claim 1.
12. The block copolymer as claimed in claim 1, in which the block copolymer is obtained by sequenced polymerization, optionally followed by one or more post-functionalizations.
13. The block copolymer as claimed in claim 1, in which the copolymer is a copolymer comprising at least one sequence of blocks AB, ABA or BAB in which said blocks A and B form a sequence without the presence of an intermediate block of different chemical nature.
14. The block copolymer as claimed in claim 1, in which p is an integer ranging from 2 to 40.
15. The block copolymer as claimed in claim 1, in which p is an integer greater than 40 and less than or equal to 100.
16. A fuel concentrate comprising one or more block copolymers as described in claim
1, mixed with an organic liquid, said organic liquid being inert with respect to the block
copolymer(s) and miscible with said fuel.
17. A fuel composition comprising:

(1) a fuel derived from one or more sources chosen from the group consisting of mineral, animal, plant and synthetic sources, and
(2) one or more block copolymers as defined in claim 1.

18. The composition as claimed in claim 17, comprising at least 5 ppm of block copolymer(s) (2).
19. The composition as claimed in claim 17, in which the fuel (1) is chosen from hydrocarbon-based fuels, fuels that are not essentially hydrocarbon-based, and mixtures thereof.