Fabrication of anisotropic material is one of the important topics and we examined to introduce “anisotropic” nature by spreading polymer-grafted particle on the medium with polymer-reactive potential. Poly (tert-butyl methacrylate) (PtBMA) was polymerized from polystyrene latex (PSL) surface by ATRP to give PtBMA-grafted PSL (PSL-PtBMA). Particle monolayer was formed at air-water and air-acidic water interfaces and the monolayer characteristics were compared by π-A isotherm measurements, SEM observations, and contact angle measurements. π-A isotherms, in particular, indicates that the interaction between polymer chains become stronger by changing the subphase condition, which suggests that anisotropicparticle monolayer formation.