Templated Synthesis of Mesoporous Superparamagnetic Polymers

Abstract

We present a novel synthetic strategy for fabricating superparamagnetic nanoparticles randomly dispersed in a mesoporous polymeric matrix. This method is based on the use of mesoporous silica materials as templates. The procedure used to obtain these mesoporous magnetic polymers consisted in: a) generating iron oxide ferrite magnetic nanoparticles (FMNP) of size ∼ 7–8 nm within the pores of the silica, b) loading the porosity of the silica/FMNP composite with a polymer (Polydivinylbenzene), c) selectively removing the silica framework from the resulting silica/FMNP/polymer composite. Such magnetic porous polymeric materials exhibit large surface areas (up to 630 m2 g–1), high pore volumes (up to 0.73 cm3 g–1) and a porosity made up of mesopores. In this way, it is possible to obtain superparamagnetic mesoporous hybrid nanocomposites that are easily manipulated by an external magnetic field and display different magnetic behaviours depending on the textural properties of the template employed.

Magnetic Metal–Organic Frameworks: γ‐Fe2O3@MOFs via Confined In Situ Pyrolysis Method for Drug Delivery

“…The lower coercive force (coercivity Hc : 1.9 Oe for ZIF‐8‐FeAA‐CS3 and 1.1 Oe for ZIF‐8‐FeAA‐I3) and remanence (retentivity Mr : 18.2E‐3 emu·g −1 for ZIF‐8‐FeAA‐CS3 and 1.8E‐3 emu·g −1 for ZIF‐8‐FeAA‐I3) indicates the superparamagnetic behavior of the γ‐Fe 2 O 3 NPs@ZIF‐8, which is mainly due to their very small size confined in the framework of ZIF‐8 matrix. It has been well‐known that the magnetic properties of nanoscale iron oxides depend on NPs size, degree of order and the specific surface coating or degree of interaction with the matrix . When Fe(acac) 3 was decomposed at 300 °C under nitrogen individually, the resultant sample exhibits a typical ferromagnetism with higher Ms value of 33.5 emu·g −1 but a remarkable magnetic hysteresis loop with corresponding Hc and Mr of 65.7 Oe and 2.8 emu·g −1 (Figure S8).…”

Novel pitaya-inspired well-defined core–shell nanospheres with ultrathin surface imprinted nanofilm from magnetic mesoporous nanosilica for highly efficient chloramphenicol removal

“…A modified method was used for the synthesis of magnetic mesoporous silica nanospheres [28]. In brief, 1.0 g of MSN and 0.6 g of Fe(NO 3 ) 3 Á9H 2 O were added to 20 ml of ethanol and the mixture were stirred at room temperature overnight.…”

Versatile strategies for fabricating polymer nanomaterials with controlled size and morphology

“…223,224 It is usually difficult to create nanoporous polymer structures under polymerization or casting conditions due to thermodynamic instability, in contrast with the case of porous silica families such as MCM-41 and SBA-15. 225 It has been found that the formation of nanoporous polymer materials is mainly affected by thermodynamic considerations such as the compatibility of templates with polymers and the conformation of polymer chains in a confinement.…”