Chiromagnetic nanoparticles and gels

Author(s)

Yeom, Jihyeon ^{[1, 2]} ; Santos, Uallisson S. ^[3] ; Chekini, Mahshid ^{[1, 4]} ; Cha, Minjeong ^{[5, 1]} ; de Moura, Andre F. ^[3] ; Kotov, Nicholas A. ^{[6, 5, 1, 4, 2]}

Affiliation

^[1] Univ Michigan, Biointerfaces Inst, Ann Arbor, MI 48109 - USA

^[2] Univ Michigan, Dept Macromol Sci & Engn, Ann Arbor, MI 48109 - USA

^[3] Univ Fed Sao Carlos, Dept Chem, BR-13565905 Sao Carlos, SP - Brazil

^[4] Univ Michigan, Dept Chem Engn, Ann Arbor, MI 48109 - USA

^[5] Univ Michigan, Dept Mat Sci & Engn, Ann Arbor, MI 48109 - USA

^[6] Univ Michigan, Dept Biomed Engn, Ann Arbor, MI 48109 - USA

• Document type: Journal article
• Source: Science; v. 359, n. 6373, p. 309+, JAN 19 2018.
• Web of Science Citations: 40

Abstract

Chiral inorganic nanostructures have high circular dichroism, but real-time control of their optical activity has so far been achieved only by irreversible chemical changes. Field modulation is a far more desirable path to chiroptical devices. We hypothesized that magnetic field modulation can be attained for chiral nanostructures with large contributions of the magnetic transition dipole moments to polarization rotation. We found that dispersions and gels of paramagnetic Co3O4 nanoparticles with chiral distortions of the crystal lattices exhibited chiroptical activity in the visible range that was 10 times as strong as that of nonparamagnetic nanoparticles of comparable size. Transparency of the nanoparticle gels to circularly polarized light beams in the ultraviolet range was reversibly modulated by magnetic fields. These phenomena were also observed for other nanoscale metal oxides with lattice distortions from imprinted amino acids and other chiral ligands. The large family of chiral ceramic nanostructures and gels can be pivotal for new technologies and knowledge at the nexus of chirality and magnetism. (AU)

• FAPESP's process: 13/07296-2 - CDMF - Center for the Development of Functional Materials
• Grantee: Elson Longo da Silva
• Support Opportunities: Research Grants - Research, Innovation and Dissemination Centers - RIDC
• FAPESP's process: 12/15147-4 - Computational study of thermodynamic association of self­-assembled systems
• Grantee: André Farias de Moura
• Support Opportunities: Regular Research Grants