effects of different nonionic surfactants on the habit modification of 5,6-dimethyl-1H-benzotriazole (5,6-DMBTA) were evaluated. Three different triblock copolymers, Pluronic (R) F-127, Pluronic (R) L44NF, and Pluronic (R) P-123 were selected as nonionic surfactants. Crystallization was achieved by pH adjustment in an aqueous solution with or without the presence of surfactants. Pluronic (R) P-123 was found to have the most dramatic effect in changing the crystal habit of 5,6-DMBTA from needles to platelets. The surfactant with a smaller hydrophobic block, Pluronic (R) L44NF, or the one with a larger hydrophilic block, Pluronic (R) F-127, yield only shorter needles for the crystal habit. This indicates that both blocks of a surfactant backbone have an impact on habit modification. Analytical data confirmed that none of the three surfactants were incorporated into the crystal lattice of 5,6-DMBTA after crystallization. All the habit modified crystals have the same crystal form as the original 5,6-DMBTA crystal sample, indicating that solely a habit modifying process took place. (C) 2013 Elsevier B.V. All rights reserved.