Temperature sensitive hydrogels cross-linked by magnetic LAPONITE® RD®: effects of particle magnetization

Abstract

This work discusses the synthesis and the properties of magnetite modified LAPONITE® RD platelets (Lap). Magnetized Lap (mLap) nanoparticles were synthesized by a co-precipitation method with different weight ratios, X = Fe₃O₄/Lap (0–2). For characterization of the samples the particle size distributions and sedimentation behavior in an external magnetic field were studied. Temperature sensible hydrogels based on N-isopropylacrylamide cross-linked by mLap were synthesized. An increased aggregation of mLap particles in aqueous suspensions has been revealed, but all the systems demonstrated high sedimentation stability. Significant effects of the value of X on the rate of sedimentation mLap particles in magnetic fields and on the swelling ability of hydrogels have been revealed. For example at X = 2, an increase in swelling by ≈2.7 was observed as compared with the swelling of hydrogels based on pure Lap nanoparticles.