Synthesis of hollow asymmetrical silica dumbbells with a movable inner core

Daisuke Nagao, Carlos M. Van Kats, Kentaro Hayasaka, Maki Sugimoto, Mikio Konno, Arnout Imhof, Alfons Van Blaaderen

Research output: Contribution to journalArticlepeer-review

54 Citations (Scopus)


Hollow asymmetrical silica dumbbells containing a movable inner core were fabricated by a template-assisted method. Three different templates were employed for the fabrication of the hollow asymmetrical dumbbells. For the preparation of the first template, silica particles were uniformly covered with a cross-linked polymethylmethacrylate (PMMA) shell and the polymerization of styrene was conducted to induce a protrusion of polystyrene (PSt) from the PMMA shell. Anisotropic colloids composed of silica, PMMA, and PSt were used as templates, coated with a silica shell, and held at 500 °C for 2 h to remove the polymer interior components of the template colloid. The heat treatment successfully produced hollow asymmetrical silica dumbbells containing an inner silica core. After being dried, approximately 50% of the inner silica particles that were originally coated with PMMA ended up in the other hollow sphere in which the PSt component existed before heat treatment, indicating that the inner silica particles could pass through the hollow asymmetrical dumbbells necks and were free to move in the interior. In the preparation of the second and third asymmetrical dumbbell templates, magnetic silica particles and titania particles, respectively, were covered with a PMMA shell to incorporate externally responsive particles into the hollow silica shells as above. The successful syntheses demonstrated the generality of our approach. The passage of the responsive particles through the dumbbells neck enabled active control of the position of the responsive particles inside the asymmetrical dumbbells by external fields.

Original languageEnglish
Pages (from-to)5208-5212
Number of pages5
Issue number7
Publication statusPublished - 2010 Apr 6


Dive into the research topics of 'Synthesis of hollow asymmetrical silica dumbbells with a movable inner core'. Together they form a unique fingerprint.

Cite this