Surface treatment process and surface treatment liquid

1. A surface treatment liquid comprising a water repellent agent and an acid imide, wherein the water repellent agent is a silylating agent.

2. The surface treatment liquid according to claim 1 , wherein the acid imide is a sulfonimide compound represented by the general formula (a1):

R A1 —SO 2 —NR A3 —SO 2 —R A2   (a1)

wherein R A1 and R A2 are the same or different, each represents a fluorine atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group, and optionally together form a cyclic group; and R A3 represents a hydrogen atom, a halogen atom, or a monovalent organic group.

3. The surface treatment liquid according to claim 2 , wherein the sulfonimide compound is a sulfonimide cyclic compound represented by the following general formula (a2):

wherein R A4 represents a substituted or unsubstituted alkylene group or a substituted or unsubstituted divalent aromatic group, and R A3 represents a hydrogen atom, a halogen atom, or a monovalent organic group.

4. The surface treatment liquid according to claim 2 , wherein the acid imide compound is at least one selected from the group consisting of acid imide 1, acid imide 2, and acid imide 3 represented by the following formulas:

5. The surface treatment liquid according to claim 1 , wherein the silylating agent comprises a silicon compound represented by the general formula (s2):

wherein R S1 , R S2 , and R S3 are the same or different and each represents an alkyl group; and Z represents an alkoxy group, an amino group, an alkylamino group, a trialkylsilylamino group, a halogen atom, or a nitrogen-containing heterocyclic group, wherein the nitrogen-containing heterocyclic group contains a nitrogen atom directly bonded to Si in the general formula (s2) as a ring-constituting atom.

6. The surface treatment liquid according to claim 5 , wherein Z in the silicon compound represented by the general formula (s2) is the nitrogen-containing heterocyclic ring.

7. The surface treatment liquid according to claim 1 , wherein the silylating agent is at least one selected from the silylating agents each represented by the following general formulae (1) to (3):

wherein R 1 represents a hydrogen atom or a saturated or unsaturated alkyl group; and R 2 represents a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, or a saturated or unsaturated heterocycloalkyl group; and R 1 and R 2 may bond to each other to form a saturated or unsaturated heterocycloalkyl group containing a nitrogen atom,

wherein R 3 represents a hydrogen atom, a methyl group, a trimethylsilyl group, or a dimethylsilyl group; and R 4 and R 5 each independently represents a hydrogen atom, a methyl group, an alkyl group, or a vinyl group,

wherein X represents O, CHR 7 , CHOR 7 , CR 7 R 7 , or NR 8 ; R 6 and R 7 each independently represents a hydrogen atom, a saturated or unsaturated alkyl group, a saturated or unsaturated cycloalkyl group, a trialkylsilyl group, a trialkylsiloxy group, an alkoxy group, a phenyl group, a phenethyl group, or an acetyl group; and R 8 represents a hydrogen atom, an alkyl group, or a trialkylsilyl group.

8. The surface treatment liquid according to claim 1 , wherein the silylating agent is at least one selected from the group consisting of N,N-dimethylaminotrimethylsilane (TMSDMA), methoxytrimethyl silane, hexamethyldisilazane (HMDS), and trimethyl silyl imidazole (TMS-imidazole) each represented by the following formulae:

9. A surface treatment process comprising exposing a surface of a substrate to the surface treatment liquid according to claim 1 to thereby hydrophobize the surface of the substrate.

10. The surface treatment liquid according to claim 5 , wherein, Z in the silicon compound represented by the general formula (s2) is the nitrogen-containing heterocyclic ring and the nitrogen-containing heterocyclic ring contains a nitrogen atom directly bonded to Si in the general formula (s2) as a ring-constituting atom.