Structural analysis of oil-compatible concentrated polymer brush neutron reflectometry

The purpose of this study is to prepare the sample with immobilized lipophilic polymer brush, and to understand its structure in a solvent by measuring it using neutron reflectometry. Polymethyl methacrylate (PMMA) and polydodecyl methacrylate (PLMA) were used as the polymer, and they were immobilized on a silicon block surface. Neutron reflectometry was applied to the polymers using a soft interface analyzer SOFIA of J-PARC. The result showed that since the polymer brush did not swell in heavy water, the film thickness of PMMA and PLMA was almost the same as those under dry state. On the other hand, the film thickness of PMMA and PLMA in deuterated toluene was approximately 135 nm and 115 nm respectively, and the swelling index representing ration of the brush length against the most extended chain length of the brush was 0.66 and 0.53 respectively. Neutron reflectometry was found to be a sufficiently effective thin film analysis technique also for lipophilic polymer brush. (A.O.)