Multi-block copolymer compositions

A copolymer composition, comprising:

• a multi-block copolymer comprising a first block and a second block, wherein the first block is substituted with an amount of heavy atoms that is effective to render it more radiopaque than the second block and wherein the multi-block copolymer has a number average molecular weight of 100 kDa or greater;
• wherein the first block of the multi-block copolymer comprises one or more units of the following Formula (A1):
• wherein
• A1 is an organic spacer group containing from 4 to 30 carbon atoms;
• X1 is I or Br;
• each a2 is independently an integer in the range of zero to three, with the proviso that at least one X1 is attached to at least one of the phenyl rings of the unit of the Formula (A1);
• wherein the second block of the multi-block copolymer comprises one or more units of the following Formula (B1):
• wherein
• each R1 is individually H or C1-6 alkyl;
• B1 is an organic spacer group containing 1-12 carbon atoms;
• m and n are each individually integers in the range of about 10 to about 500;
• wherein the multi-block copolymer is in the form of a single phase having a glass transition temperature for the single phase that is greater than 37° C.;
• or
• wherein the copolymer composition comprises a discontinuous first polymer phase having a first glass transition temperature greater than 37° C. and a continuous second polymer phase having a second glass transition temperature greater than 37° C., the discontinuous first polymer phase being relatively enriched in the first blocks of the multi-block copolymer and the continuous second polymer phase being relatively enriched in the second blocks of the multi-block copolymer, and wherein the first polymer phase has an average domain size of 10 μm or less;
• and
• wherein the weight ratio of the units of the Formula (A1) to the units of the Formula (B1) is in the range of 7:3 to 3:7.