Do, Taegu Ko, Young Gun Jung, Youngkyun Chun, Youngsang Choi, Ung Su 2024-01-20T00:02:26Z 2024-01-20T00:02:26Z 2021-09-03 2017-12 2050-7526 https://pubs.kist.re.kr/handle/201004/122017 Inspired by the electromigration phenomenon in biomolecules, we fabricated various oligoamine-modified polyacrylonitrile (PAN) particles to aim for a negative ER effect. A noteworthy result is that the modified PAN with a short oligoamine shows a positive ER effect owing to the improved dielectric property, while the modified PAN with a long oligoamine presents a negative ER effect due to the enhanced electrophoretic force. This is the first time that the negative ER effect is controllably obtained, differentiating our invention from previous trial-and-error based methods where the ER effects were coincidentally acquired by numerous experiments. Interestingly, the synthesized negative ER particles are migrated toward the anode at the DC electric fields, which is analogous with the electromigration phenomenon in biomolecules. In conclusion, the introduction of an oligoamine on the surface of the ER particles can improve both the positive and negative ER properties by controlling the length of oligoamines and manipulating the competitive effect between the dielectric property and the electrophoretic effect. We believe that our study can offer a new strategy for the development of both the positive ER and the negative ER materials. Moreover, we expect that our invention will facilitate the use of a negative ER suspension in various industries. English ROYAL SOC CHEMISTRY Design of negative electrorheological materials inspired by electrophoretic separation of biomolecules Article 10.1039/c7tc03566g 1 JOURNAL OF MATERIALS CHEMISTRY C, v.5, no.45, pp.11683 - 11693 JOURNAL OF MATERIALS CHEMISTRY C 5 45 11683 11693 N scie scopus 000416127400003 2-s2.0-85035028168 Materials Science, Multidisciplinary Physics, Applied Materials Science Physics Article CHITOSAN DISPERSED SUSPENSION YIELD-STRESS ELECTROMIGRATION METHODS ELECTRIC-FIELDS SHEAR BEHAVIOR FLUIDS PARTICLES NANOPARTICLES PERFORMANCE COMPOSITE ER materials Negative ER effect PAN DC ekectric field