Nonreversible surface relief formation in thin films of cinnamate derivatives containing benzoxazine structure

• Published in: Journal of applied polymer science 2022-06, Vol.139 (21), p.n/a
• Main Authors: Doi, Takashi, Rozhanskii, Igor, Nakamura, Takahiro, Shimokawa, Tsutomu
• Format: Article
• Language: English
• Subjects: benzoxazine; Benzoxazines; cinnamate; Materials science; Microfluidics; Micropatterning; photodimerization; Photolithography; Polymers; Silicon wafers; surface relief structure; thermal curing; Thickness; Thin films; Ultraviolet radiation
• ISSN: 0021-8995; 1097-4628
• DOI: 10.1002/app.52173

A novel, nonreversible surface relief (SR) system was developed using polymerizable low‐molecular‐weight compounds containing two or three [(E)‐3‐[4‐(6‐methyl‐2,4‐dihydro‐1,3‐benzoxazin‐3‐yl)phenyl]prop‐2‐enoyl]oxy units in which photoreactive cinnamate moieties and thermally curable benzoxazine moieties are included. The SR structure formation was conducted using thin films (thickness: 1.5 μm) on silicon wafers through a two‐step procedure including micropatterned ultraviolet irradiation at 23°C and then heating to induce the SR pattern formation. All of the four compounds synthesized in this study showed submicron‐height SR structure on their films. After being thermally treated at 200°C for 1 h, the thin films became insoluble, which ensured the formation of crosslinked network structures. The obtained nonreversible SR system is expected to be a candidate for microfluidic channel materials for cooling semiconductor chips as well as an alternative option for photolithography.