Dynamic contact angles and their hysteresis for LB films of p-phenylenediacrylic acid monodecylester (p-PDAmC10) and poly(vinyl alcohol) bearing p-PDAmC10 as the side chain (PVA-p-PDAmC10) were investigated by the Wilhelmy plate method. The hysteresis loops of the contact angle showed that: (1) PVA-p-PDAmC10 forms a more stable LB film than that of p-PDAmC10 which is easily detached when contacted with water; (2) PVA-p-PDAmC10 LB film transferred at high surface pressure (greater than or equal to 20 mN/m) with more than 3 layers can provide a uniform surface and same wettability; (3) PVA-p-PDAmC10 LB film has a very large contact angle hysteresis (>80 degrees), which means that reorientation of the surface configuration takes place dramatically; and (4) the hysteresis can be greatly reduced (<30) by UV-irradiation due to the photocycloaddition in the side chains of PVA-p-PDAmC10.