Design, synthesis, and photosensitive performance of polymethacrylate‐positive photoresist‐bearing o‐nitrobenzyl group

Abstract

Novel polymethacrylate‐positive photoresist‐bearing o‐nitrobenzyl group was described herein. The matrix polymer (PCHIBNB) was synthesized by copolymerization of cyclohexyl methacrylate (CHMA), isobornyl methacrylate (IBMA), and o‐nitrobenzyl methacrylate (NBMA) via reversible addition fragmentation chain transfer (RAFT) polymerization method. After UV irradiation, the o‐nitrobenzyl groups of PCHIBNB were photocleaved and the resulting carboxyl groups were highly alkali‐soluble, so that the matrix polymer could be etched by mild alkali solution with no requirements of photosensitizers or photoacid generators. PCHIBNB was characterized by Fourier transform infrared spectroscopy (FTIR), proton nuclear magnetic resonance (1H‐NMR) spectroscopy, and gel permeation chromatography (GPC). The photocleavable behaviors of PCHIBNB were determined by FTIR, 1H‐NMR, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) analysis. The resist formulated with this polymer and cast in tetrahydrofuran (THF) solution showed 10 μm × 10 μm square pattern using a mercury–xenon lamp in a contact printing mode and tetramethyl‐ammonium hydroxide aqueous solution as a developer. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41733.

Photoinduced Modulation of Polymeric Interfacial Behavior Controlling Thin-Film Block Copolymer Wetting

“…The compositions of the copolymers ( F st and F NBMA ) were obtained using 1 H NMR spectroscopy through the integration of the characteristic peaks of a benzene ring in a styrene unit at 6.3–7.2 ppm, a methyl group in a GMA unit at 4.1–4.4 ppm, and a benzene ring in a nitrobenzyl group in an NBMA unit at 7.9–8.1 ppm (Figure S1). − The resulting F st and F NBMA values of the synthesized PSNG were found to be 0.925 and 0.041, respectively, and F NMBA of the PNG was observed to be 0.893. It is noted that Đ of both copolymers were found to be higher than 1.5, deviated from a typical value of RAFT polymerization.…”

“…The TGA curve for the PNG showed three stages of mass reductions, with the first onset temperature at ≈190 °C, and the second and third onset temperatures at ≈280 and ≈370 °C (Figure ). The first and second mass reductions showed a mass loss of approximately 63%, which is attributed to the loss of a 2-nitrobenzyl ester group (typically degraded in the range of 200–300 °C), , and the loss of a glycidyl group . The decomposition of the main chain of the copolymer occurred at near 350 °C.…”

Micellar assembly of a photo- and temperature-responsive amphiphilic block copolymer for controlled release

“…Fig. 1c shows the FTIR spectra of the polymer PNIPAM and the copolymer P1, from which it can be seen that an absorbance peak at ∼1735 cm −1 assigned to the ester groups of PNBM appeared in the spectrum of the copolymer, 29 indicating that the targeted block copolymer was indeed achieved. Fig.…”

Trigger responsive polymeric nanocarriers for cancer therapy

“…O-Nitrobenzyl alcohol derivatives were used primarily as photo-labile protecting groups of carboxylic acid and amine groups in polypeptide or organic synthesis. 234,244 Later it was shifted to photoresponsive polymer chemistry for the gene-ration of amphiphilic di-or tri-block polymers in order to make micelles for light driven release of cargo in a spatiotemporal manner. This hydrophobic photosensitive group acts as protector of the hydrophilic carboxylic group, preventing its exposure to the outer aqueous environment, and the whole polymer exhibits hydrophobicity.…”