Hydrophilic polymer having silane coupling group terminal and lithographic printing plate base

A polymer compound having weight average molecular weight of 1,000 to 100,000 and comprising:

• i) a polymer structure represented by —(CHR3—CR4(-L1-Y1))x—(CHR5—CR6(-L2-Y2))y—;
• and
• ii) a silane coupling group represented by —S—(CH2)n—Si—(R1)m(OR2)3-m, as a terminal of the polymer structure,
• wherein R1, R2, R3, R4, R5, and R6 each independently represents a hydrogen atom or a hydrocarbon group having 1 to 8 carbon atoms;
• m represents 0, 1 or 2;
• n represents an integer of 1 to 8;
• x is 100 to 1 mol %;
• y is 0 to 99 mol %;
• x+y=100 mol %;
• L1 and L2 each independently represents a single bond or an organic connecting group;
• and Y1 and Y2 each independently represents —N(R7)(R8), —OH, —NHCOR7, —COR7, —CO2M, or —SO3M, wherein R7 and R8 each independently represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms and M represents a hydrogen atom, an alkali metal, an alkaline earth metal, or an onium.