The most frequently used are the linear diblock or triblock copolymers. In these cases, the block copolymer has one block that is hydrophobic; the other block or blocks are hydrophilic. Other morphologies used include comb copolymers,[4][5] where the backbone block is hydrophilic and the comb branches are hydrophobic, and dendronized block copolymers,[6] where the dendrimer portion is hydrophilic.