Grafting of titanium dioxide microspheres with a temperature-responsive polymer via surface-initiated atom transfer radical polymerization without the use of silane coupling agents

• Published in: Polymer international Vol. 62; no. 5; pp. 836 - 841
• Main Authors: Smirnov, Eugene A, Meledina, Maria A, Garshev, Alexey V, Chelpanov, Vitaly I, Frost, Sven, Wieneke, Jan U, Ulbricht, Mathias
• Format: Journal Article
• Language: English
• Published: Chichester, UK John Wiley & Sons, Ltd 01-05-2013; Wiley; Wiley Subscription Services, Inc
• Subjects: atom transfer radical polymerization (ATRP); Dispersions; Dynamical systems; Dynamics; graft copolymers; Hydroxyl groups; Microspheres; Polymerization; Radicals; stimuli-sensitive polymers; temperature-responsive polymers; titania microspheres; Titanium dioxide
• ISSN: 0959-8103; 1097-0126
• DOI: 10.1002/pi.4377

Titania microspheres with narrow size distribution and diameters of about 1 µm were prepared and subsequently functionalized using surface‐initiated atom transfer radical polymerization (ATRP) of N‐isopropylacrylamide. The ATRP initiator was immobilized on the particle surface via acylation of surface hydroxyl groups with α‐bromoisobutyryl bromide. Subsequently, an established ATRP reaction system was used for the preparation of titania surface‐grafted poly(N‐isopropylacrylamide) (PNiPAAm). Characterization was performed with electron microscopies, X‐ray diffraction, infrared spectroscopy and dynamic light scattering. It was found that the particle size in aqueous dispersions changed reversibly with temperature as expected for a shell of PNiPAAm, a polymer with a lower critical solution temperature at 32 °C. This confirmed the successful preparation of functional, stimuli‐responsive TiO2 microparticles via a straightforward controlled surface‐initiated polymerization method.
Titania microspheres with diameters of about 1 µm were prepared and successfully functionalized using surface‐initiated atom transfer radical polymerization of N‐isopropylacrylamide without the use of silane coupling agents.