Thickness Control of Colloidal Crystals with a Substrate Dipped at a Tilted Angle into a Colloidal Suspension

When a glass substrate is dipped into a colloidal suspension, the contact line shape is changed with the angle of tilt. These variations in the contact line shape indicate a possibility for thickness control of colloidal crystals. Thus, we have investigated how the thickness of colloidal crystals is changed with specific tilted angles (−10°, 0°, 10°, 20°, and 30°, respectively). As a glass substrate is tilted more (from −10° to 30°), a smoother and thicker contact line is formed and thicker colloidal crystals are obtained. In addition, it is possible to explain why multiple contact line patterns are formed on the glass substrate. It was found that to fabricate three-dimensional colloidal crystals with an even surface, the evaporation rate of water should be reduced and/or the glass substrate should be tilted over 10° in our cases.