**4.4 3-D Fabrication of PTFE**

Because the PCT technique successfully provided PMMA 3-D structures, we adapted the PCT technique to expose PTFE while the stage was in motion. Fabrication of 3-D PTFE microstructures using other techniques has also been reported, including 3-D PMMA structures (Nakamura and Tabata, 2006; Nishi et al., 1999). Figure 23 shows 3-D PTFE structures fabricated using the PCT technique with a triangular mask pattern. Figure 23A shows a structure in which the PTFE surface temperature was 140°C, and Figure 23B shows a structure in which the PTFE surface temperature was 200°C. As shown in the figure, higher PTFE temperatures correspond to enhanced surface roughness. Figure 24 shows the target forms and 3-D PTFE structures fabricated using the PCT technique with other mask patterns.

Fig. 23. 3-D PTFE structures fabricated using the PCT technique with a triangular mask pattern; (A) PTFE surface temperature was 140°C; and (B) PTFE surface temperature was 200°C

Fig. 24. Target forms and 3-D PTFE structures fabricated using the PCT technique with other mask patterns; (A) is utilizing sine-curved mask pattern; and (B) is utilizing semicircular mask pattern
