A nanostructured copolymer matrix has successfully separated oligonucleotides with high resolution by CE using a very short separation channel which simulates the real microchip condition for the first time. The triblock copolymer, E45B14E45 (B20-5000) with E, B, and subscript denoting oxyethylene, oxybutylene, and segment length, respectively, has a unique temperature-dependent viscosity-adjustable property and a dynamic coating ability in 1 x TBE buffer (89 mM Tris, 89 mM boric acid, 2 mM EDTA in Milli-Q water). The B-block is hydrophilic at low temperatures, e.g., 4 degrees C, and the polymer solution has a very low viscosity of about 100 cP in a 32.5% w/v solution. At room temperatures, the B-block becomes hydrophobic due to a breakdown of hydrogen bonds between B-blocks and water, and the polymer matrix forms a body-centered cubic structure at high concentrations. Oligonucleotide sizing markers ranging from 8 to 32 base could be successfully separated with one-base resolution in a 1.5 cm long separation channel by E45B14E45 in its gel-like state.