A compound comprising a building block according to formula wherein each A represents a unit independently selected from the following formulae and and wherein R a1, R a2, R a3 and R a5 are each selected independently from the group consisting of C1-C12-alkanediyl and -(CH 2) c -[CH(R a6)-CH 2 -O] d -(CH 2) e - wherein c is an integer ranging from 0 to 3; d is an integer ranging from 1 to 100; e is an integer ranging from 1 to 3; each R a6 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl; each R a4 is independently selected from the group consisting of alkanediyl, arenediyl and -(CH 2) f -[CH(R a7)-CH 2 -O] g -(CH 2) h -, wherein f is an integer ranging from 0 to 3; g is an integer ranging from 1 to 100; h is an integer ranging from 1 to 3; each R a7 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl; each X 1 and X 2 are independently selected from the group consisting of wherein Z is selected from -CH 2 -, O, S; z and z' are integers independently ranging from 1 to 6, each R a8 and R a9 are independently selected from the group consisting of hydrogen, alkyl, aryl, aralkyl and -CH 2 -CH 2 -(OCH 2 CH 2) y -OH wherein y is an integer from 1 to 4; each Y 1, Y 2 and Y 3 are independently selected from the group consisting of O and N(R a10) wherein each R a10 is independently selected from the group consisting of hydrogen, alkyl, aryl and aralkyl; a is an integer ranging from 1 to 40; and each D is independently selected from the group consisting of -CH 2 -CH -CH 2 -, -CH 2 -CH -CH 2 -, -(CH 2) i -[CH(R d1)-CH 2 -O] j -(CH 2) k - and -CH 2 -CH -(CH 2) l -[CH(R d2)-CH 2 -O] m -(CH 2) n -CH -CH 2 - wherein i is an integer ranging from 0 to 3; j is an integer ranging from 1 to 100; k is an integer ranging from 1 to 3; each R d1 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl; I is an integer ranging from 1 to 3; m is an integer ranging from 1 to 100; n is an integer ranging from 1 to 3; each R d2 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl. R a1, R a2, R a3 and R a5 are each selected independently from the group consisting of C1-C12-alkanediyl and -(CH 2) c -[CH(R a6)-CH 2 -O] d -(CH 2) e - wherein c is an integer ranging from 0 to 3; d is an integer ranging from 1 to 100; e is an integer ranging from 1 to 3; each R a6 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl; each R a4 is independently selected from the group consisting of alkanediyl, arenediyl and -(CH 2) f -[CH(R a7)-CH 2 -O] g -(CH 2) h -, wherein f is an integer ranging from 0 to 3; g is an integer ranging from 1 to 100; h is an integer ranging from 1 to 3; each R a7 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl; each X 1 and X 2 are independently selected from the group consisting of wherein Z is selected from -CH 2 -, O, S; z and z' are integers independently ranging from 1 to 6, each R a8 and R a9 are independently selected from the group consisting of hydrogen, alkyl, aryl, aralkyl and -CH 2 -CH 2 -(OCH 2 CH 2) y -OH wherein y is an integer from 1 to 4; each Y 1, Y 2 and Y 3 are independently selected from the group consisting of O and N(R a10) wherein each R a10 is independently selected from the group consisting of hydrogen, alkyl, aryl and aralkyl; a is an integer ranging from 1 to 40; and each D is independently selected from the group consisting of -CH 2 -CH -CH 2 -, -CH 2 -CH -CH 2 -, -(CH 2) i -[CH(R d1)-CH 2 -O] j -(CH 2) k - and -CH 2 -CH -(CH 2) l -[CH(R d2)-CH 2 -O] m -(CH 2) n -CH -CH 2 - wherein i is an integer ranging from 0 to 3; j is an integer ranging from 1 to 100; k is an integer ranging from 1 to 3; each R d1 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl; I is an integer ranging from 1 to 3; m is an integer ranging from 1 to 100; n is an integer ranging from 1 to 3; each R d2 is independently from each other selected from the group consisting of hydrogen, alkyl, aryl and aralkyl.