Synthesis of Breathing Metallopolymer Hollow Spheres for Redox-Controlled Release

Abstract

A convenient synthetic approach for the preparation of uniform metallopolymer-containing hollow spheres based on 2-(methacryloyloxy)ethyl ferrocenecarboxylate (FcMA) as monomer by sequential starved feed emulsion polymerization is described. Core/shell particles consisting of a noncrosslinked poly(methyl methacrylate) core and a slightly crosslinked ferrocene-containing shell allows for the simple dissolution of core material and, thus, monodisperse metallopolymer hollow spheres are obtained. Since PFcMA is incorporated in the particle shell, herein investigated hollow spheres can be addressed by external triggers, i.e., solvent variation and redox chemistry in order to change the particle swelling capability. PFcMA-containing core/shell particles and hollow spheres are characterized by transmission electron microscope (TEM), scanning electron microscopy, cryogenic TEM, thermogravimetric analysis, and dynamic light scattering in terms of size, size distribution, hollow sphere character, redox-responsiveness, and composition. Moreover, the general suitability of prepared stimulus-responsive nanocapsules for the use in catch-release systems is demonstrated by loading the nanocapsules with malachite green as model payload followed by release studies.

Recent Trends in Metallopolymer Design: Redox‐Controlled Surfaces, Porous Membranes, and Switchable Optical Materials Using Ferrocene‐Containing Polymers

“…section 7). [67,68] In summary,f errocene-containing polymers can be prepared for the creationo fm any polymer architectures in the recent past. Advances in polymerc hemistry as well as recent efforts in metallopolymer analytics have led to al arge variety of novel redox-responsive functional materials.…”

“…In a recent study, FcMA monomer was successfully polymerized by means of radical polymerization in emulsion leading to monodisperse metallopolymer‐based and stimuli‐responsive particles featuring a core‐interlayer‐shell (CIS) architecture for optical applications and the preparation of iron‐based ceramics (cf. section 7) …”

“…The investigated microcapsules were used to reversibly change the permeability and the size by chemical redox agents for the controlled loading or release of dextran. As another example, the use of sequential starved‐feed emulsion polymerization technique allows for the preparation of highly monodisperse ferrocene‐containing core/shell polymer nanoparticles with precisely adjustable diameter, shell thickness and chemical composition . Within a study by Scheid et al.…”

Recent Advances and Future Prospects of Aggregation‐induced Emission Carbohydrate Polymers

“…It is well known that stimuli responsive polymers are very important candidates for biomedical applications. A large number of biomaterials with one or multiple stimuli responses (e.g., to oxidation, reduction, temperature, pH, light and glucose etc) have been developed for various applications . Therefore, through integration of these responsive components with AIE‐active dyes and carbohydrate polymers, a considerably large number of multifunctional AIE‐active FONs could theoretically be fabricated.…”

Ferrocene-Modified Block Copolymers for the Preparation of Smart Porous Membranes

“…In general, among the broad variety of stimuli-responsive mechanisms, redox reactions induced by the addition of oxidation or reducing agents or by applying electrical potentials are much less investigated. In the recent past, the ferrocene/ferrocenium redox couple in metallopolymers has attracted significant interest due to the unique capability of (electro)chemical switching between hydrophobic ferrocene and comparably hydrophilic ferrocenium moieties [17][18][19][20][21][22][23][24]. In the field of (nano)porous structures, ionic permeation across smart membranes have been modulated by introducing redox-active moieties or polymers at the inner pore walls of the membrane [25][26][27][28].…”