A novel type of elastomers with silver nanoparticles (AgNP) as cross-linkers has been obtained by a quantitative one-phase bottom-up procedure based on α,ω-dimercapto-poly(cis-1,4-isoprene) (PIP). This telechelic polymer with high cis-content of >80% and near-quantitative functionalization degree has been synthesized in a one-pot procedure by anionic polymerization. It was cross-linked by coordination of the thiol groups to in-situ synthesized AgNP to yield a repeatedly melt-processable elastomer. It was found that the E-modulus increased up to an ideal ratio of AgNP to PIP and decreases drastically with AgNP oversaturation due to decreasing cross-linking density. Swelling experiments were in agreement with these results. The cross-linking of telechelic polymers with metal nanoparticles has been applied to other metals and polymers, leading to cross-linked materials in all cases. Antibacterial properties of the silver-containing elastomers were found by the Kirby–Bauer test.
Polymer cages prepared by etching of gold nanoparticles from polymer templates by the “grafting around” method are designed for selective separation of metal nanoparticles. The separation process is demonstrated as a fast biphasic ligand exchange reaction. The high separation efficiency and size selectivity of the polymer cage is verified by comparison with the linear block copolymer.
A template synthesis allows the preparation of monodisperse nanoparticles with high reproducibility and independent from self-assembly requirements. Tailor-made polymer cages were used for the preparation of nanoparticles, which were made of cross-linked macromolecules with pendant thiol groups. Gold nanoparticles (AuNPs) were prepared in the polymer cages in situ, by using different amounts of cages versus gold. The polymer cages exhibited a certain capacity, below which the AuNPs could be grown with excellent control over the size and shape. Control experiments with a linear diblock copolymer showed a continuous increase in the AuNP size as the gold feed increased. This completely different behavior regarding the AuNP size evolution was attributed to the flexibility of the polymer chain depending on cross-linking. Moreover, the polymer cages were suitable for the encapsulation of AgNPs, PdNPs, and PtNPs by the in situ method.
Dry powders embedded with gold nanoparticles (AuNPs) are produced by spray‐drying technique from an aqueous AuNP dispersion in a poly(vinyl alcohol) (PVA) or poly(vinyl pyrrolidone) (PVP) matrix. The prepared powders consist of AuNPs stabilized in hollow capsules of PVA (PVA@AuNP) or PVP (PVP@AuNP) with an average diameter of several micrometers. The AuNP powders are dispersible in water and no agglomeration triggered by the spray drying process of AuNPs is observed. The PVA@AuNP powders are coextruded with polycaprolactone to demonstrate the industrial application of dry‐state AuNPs. With PVP@AuNP the incorporation of AuNP into other stabilizing polymers via ligand exchange method is facilitated. After each step, the active surface of the AuNPs was tested by catalytic studies.
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