A tri-block copolymer includes a first end block consisting of a hydrophobic, nano-fiber forming polymer, wherein the first end block is present in the tri-block copolymer at a weight percentage ranging from about 10% to about 89%; a middle block attached to the first end block, the middle block consisting of a hydrophilic polymer, wherein the middle block is present in the tri-block copolymer at a weight percentage ranging from about 1% to about 89%; and a second end block attached to the middle block, the second end block consisting of a temperature-responsive polymer, wherein the second end block is present in the tri-block copolymer at a weight percentage ranging from about 1% to about 89%.