Preparation of composite microneedles from a suspension of carbonyl iron microparticles in fluoroorganic binder

Abstract

The method was proposed for the preparation of composite iron-fluoropolymeric magnetic needles up to 20 mm in length by self-assembly of carbonyl iron microparticles in a solution of the LF-32L fluoroorganic varnish in a vertical magnetic field. The resistance of the generated structures toward aqueous solutions of acids increases in the series HCl—HNO₃—H₂SO₄. The structures withstand heating to 200 °С. The dissolution of iron results in to formation of porous fluoropolymeric shells curling or retaining the linear shape after the loss of the filler. The properties of the needles and shells were studied by IR spectroscopy, scanning electron microscopy, atomic force microscopy, and optical microscopy.