A polymer photocatalyst system was synthesized using a poly(styrene-block-acrylic acid) (PS-b-PAA) containing TiO2 gel without calcination, and its activity characteristics were assessed with methylene blue (MB) photodegradation test in water under visible light irradiation. The initial photodegradation activity was controllable by the polymer chain length and PAA/PS molar ratio. The longer polymer chain length provoked the activity decrease by macromolecular crowding effect. The lower molar ratio did an increase in the photocatalytic surface area by generation of a large number of anatase TiO2 crystal nuclei, leading to the activity increase. The copper phthalocyanine (CuPc) loading remarkably improved the activity. A higher active site was formed on the interface and showed good recycling performance. (C) 2018 Elsevier Inc. All rights reserved.