A polymeric photoinitiator, being a co-polymer of at least one monomer with at least one monomer, wherein: - monomer is a photoinitiator monomer of the formula: in which: Pi is a photoinitiator moiety; Z is a linker moiety; X 1 and X 2 are independently selected from optionally substituted C 1 -C 12 alkylene, optionally substituted C 1 -C 12 alkenylene, optionally substituted heterocyclyl, -O-, -S-, -NR 2 -, -C(=O)-, -C(=NR 2)-, -Si(R 2) 2 -O-, optionally substituted aryl, and combinations thereof, wherein R 2 is H or optionally substituted C 1 -C 12 alkyl; wherein X 1 and X 2 or a part thereof may be linked to one another or to Z to form one or more ring structures; wherein Z, X 1 and X 2 are selected such that N is a tertiary amine; W 1 and W 2 are functional groups independently selected from alcohol, primary amine, secondary amine, thiol, alkoxy silane, silane esters of carboxylic acids, isocyanate, isothiocyanate, carboxylic acid, chloroformate, primary amide, secondary amide, urethane or urea groups; - monomer comprises at least two functional groups W 3 and W 4, said W 3 and W 4 being independently selected from alcohol, primary amine, secondary amine, thiol, alkoxy silane, silane esters of carboxylic acids, isocyanate, isothiocyanate, carboxylic acid, chloroformate, primary amide, secondary amide, urethane or urea groups, wherein W 1, W 2, W 3 and W 4 are selected such that - in the co-polymerization of monomers and - W 1 reacts with W 3 to form a urethane, thiourethane, urea, thiourea, ester, ether, amide, carbonate, allophanate or biuret moiety, and W 2 reacts with W 4 to form a urethane, thiourethane, urea, thiourea, ester, ether, amide, carbonate, allophanate or biuret moiety. - monomer is a photoinitiator monomer of the formula: in which: Pi is a photoinitiator moiety; Z is a linker moiety; X 1 and X 2 are independently selected from optionally substituted C 1 -C 12 alkylene, optionally substituted C 1 -C 12 alkenylene, optionally substituted heterocyclyl, -O-, -S-, -NR 2 -, -C(=O)-, -C(=NR 2)-, -Si(R 2) 2 -O-, optionally substituted aryl, and combinations thereof, wherein R 2 is H or optionally substituted C 1 -C 12 alkyl; wherein X 1 and X 2 or a part thereof may be linked to one another or to Z to form one or more ring structures; wherein Z, X 1 and X 2 are selected such that N is a tertiary amine; W 1 and W 2 are functional groups independently selected from alcohol, primary amine, secondary amine, thiol, alkoxy silane, silane esters of carboxylic acids, isocyanate, isothiocyanate, carboxylic acid, chloroformate, primary amide, secondary amide, urethane or urea groups; Pi is a photoinitiator moiety; Z is a linker moiety; X 1 and X 2 are independently selected from optionally substituted C 1 -C 12 alkylene, optionally substituted C 1 -C 12 alkenylene, optionally substituted heterocyclyl, -O-, -S-, -NR 2 -, -C(=O)-, -C(=NR 2)-, -Si(R 2) 2 -O-, optionally substituted aryl, and combinations thereof, wherein R 2 is H or optionally substituted C 1 -C 12 alkyl; wherein X 1 and X 2 or a part thereof may be linked to one another or to Z to form one or more ring structures; wherein Z, X 1 and X 2 are selected such that N is a tertiary amine; W 1 and W 2 are functional groups independently selected from alcohol, primary amine, secondary amine, thiol, alkoxy silane, silane esters of carboxylic acids, isocyanate, isothiocyanate, carboxylic acid, chloroformate, primary amide, secondary amide, urethane or urea groups; - monomer comprises at least two functional groups W 3 and W 4, said W 3 and W 4 being independently selected from alcohol, primary amine, secondary amine, thiol, alkoxy silane, silane esters of carboxylic acids, isocyanate, isothiocyanate, carboxylic acid, chloroformate, primary amide, secondary amide, urethane or urea groups, wherein W 1, W 2, W 3 and W 4 are selected such that - in the co-polymerization of monomers and - W 1 reacts with W 3 to form a urethane, thiourethane, urea, thiourea, ester, ether, amide, carbonate, allophanate or biuret moiety, and W 2 reacts with W 4 to form a urethane, thiourethane, urea, thiourea, ester, ether, amide, carbonate, allophanate or biuret moiety.