Atom transfer radical polymerization (ATRP) was applied to the synthesis of amphiphilic cylindrical polymer brushes by using the "grafting from" technique. The procedure included the following steps: (1) ATRP of 2-hydroxyethyl methacrylate (HEMA) gave well-defined poly(HEMA), (2) subsequent esterification of the pendant hydroxy groups of poly(HEMA) with 2-bromoisobutyryl bromide yielded a polyinitiator, poly(2-(2-bromoisobutyryloxy)ethyl methacrylate (PBIEM), (3) ATRP of various monomers (tent-butyl acrylate, or styrene) using PBIEM as polyinitiator yielded cylindrical brushes with homopolymer side chains, (4) addition of a second monomer (styrene or tent-butyl acrylate) formed the cylindrical brushes with diblock copolymer side chains (core-shell cylinders), and (5) hydrolysis of the poly(tert-butyl acrylate) (PtBA) block of the side chains to poly(acrylic acid) (PAA) formed amphiphilic core-shell polymer brushes. By using this technique, well-defined core-shell cylindrical polymer brushes with polystyrene (PS), PtBA, PS-b-PtBA, PtBA-b-PS, PS-b-PAA, or PAA-b-PS as side chains were successfully synthesized. The molecular weights and radii of gyration of the polymer brushes were obtained by static light scattering in THF. The absence of inter/intra-macromolecular coupling reactions during ATRP synthesis was confirmed by GPC, NMR, and MALDI-TOF analyses of the side chains and scanning force microscopy (SFM). Single wormlike unimolecular nanocylinders are clearly visualized on a mica surface while aggregates are usually observed on a SiOx surface. The brushes with PS-b-PtBA side chains were hydrolyzed to PS-b-PAA side chains forming unimolecular wormlike micelles. These unimolecular micelles showed a unique response to solvent quality, as indicated by H-1 NMR and dynamic light scattering.