Flowability of Gel-Matrix and Magnetorheological Response for Carrageenan Magnetic Hydrogels

• Published in: Gels 2021-05, Vol.7 (2), p.56
• Main Authors: Ikeda, Junko, Kurihara, Tomoki, Ogura, Keiju, Akama, Shota, Kawai, Mika, Mitsumata, Tetsu
• Format: Article
• Language: English
• Subjects: Carbonyls; Carrageenan; Hydrogels; Iron; Magnetic fields; magnetic gel; magnetorheologylogy; Polymers; Rheological properties; Shear stress; stimuli-responsive material; Storage modulus; Strain; Stresses; Temperature; viscoelastic property; Viscoelasticity
• ISSN: 2310-2861; 2310-2861
• DOI: 10.3390/gels7020056

The relationship between rheological features in the absence of a magnetic field and magnetic response was investigated for κ-carrageenan magnetic hydrogels containing carbonyl iron particles. The concentration of carrageenan was varied from 1.0 to 5.0 wt%, while the concentration of carbonyl iron was kept at 70 wt%. The magnetic response revealed that the change in storage modulus Δ decreased inversely proportional to the carrageenan concentration. A characteristic strain γ where ' equals to ″ was seen in a strain range of 10 . It was found that Δ ' was inversely proportional to the characteristic stress at γ . Another characteristic strain γ where the loss tangent significantly increased was also analyzed. Similar to the behavior of γ , Δ ' was inversely proportional to γ . The characteristic stresses at γ and γ were distributed at 80-720 Pa and 40-310 Pa, respectively. It was revealed that a giant magnetorheology higher than 1 MPa can be observed when the characteristic stresses at γ and γ are below approximately 240 Pa and 110 Pa, respectively.