Copolymerization of Mesoporous Styrene-Bridged Organosilica Nanoparticles with Functional Monomers for the Stimuli-Responsive Remediation of Water

For every mass product, there are problems associated with the resulting waste. Residues of hormones in urine cannot be removed sufficiently from wastewater, and this has undesired consequences. An ideal adsorbent would take up the impurity, enable a simple separation and recyclability. Polymer colloids with high affinity towards the drug, accessible porosity, high surface area, and stimuli-responsive properties would be candidates, but such a complex system does not exist. Here, porous vinyl-functionalized organosilica nanoparticles prepared from a styrene bridged sol-gel precursor act as monomers. Initiation of the polymerization at the pore walls and addition of functional monomers result in a special copolymer, which is covalently linked to the surface and covers it. An orthogonal modification of external surface was done by click attachment of a thermoresponsive polymer. The final core-shell system is able to remove quantitatively hydrophobic molecules such as the hormone progesterone from water. A change of temperature closes the pores and induces the aggregation of the particles. After separation one can reopen the particles and recycle them. © 2020 The Authors. Published by Wiley-VCH Gmb

Meso-Architecture Block Copolymers with High Surface Area Styrene-Bridged Organosilica Particles as Constituent for the Stimuli-Responsive Remediation of Water

The development of drugs for birth-control has changed society, and they are used by billions of woman on an every day basis. As for every mass product, there are problems associated with the waste it causes. One has found that residues of hormones in the urine of woman cannot be removed sufficiently from waste-water and this, in-turn, has already observable and undesired consequences in the biosphere. Apart from the removal of drugs, one is in general seeking new methods for the removal of hydrophobic impurities from waste-water. An ideal system would quantitatively take up the impurity, entrap it followed by preferably simple separation. Finally, one wants to reuse the absorbent, which implies the possibility for regeneration and recycling. Such as complex set of tasks requires a relatively complex materials architecture. Functional organic polymers with high affinity towards the drug, with stable open porosity and high surface area, stimuli-responsive properties and in the form of colloidal dispersions could do the job. Unfortunately, such a system does not exist. We solved this problem by generating mesoporous organosilica nanoparticles, which are monomers at the same time. Initiation of the polymerization reaction by surface-bound pore-walls leads to the formation of a special type of block-copolymer. The pore-walls are covered by the polymer, which cannot leach. An orthogonal modification was achieved by modification of the external surfaces of the particles with a thermoresponsive polymer by click-chemistry. The final core-shell system was able to remove hydrophobic molecules such as the hormone progesterone from water. A change of temperature induces the collapse of the thermoresponsive polymer, which closes the pores and induces aggregation of the particles. After separation of the particles, and thus also the entrapped impurity, from the solvent, one can re-open the pores, which leads to a release of the adsorbed compound(s)

Copolymerization of Mesoporous Styrene-Bridged Organosilica Nanoparticles with Functional Monomers for the Stimuli-Responsive Remediation of Water

For every mass product, there are problems associated with the resulting waste. Residues of hormones in urine cannot be removed sufficiently from wastewater, and this has undesired consequences. An ideal adsorbent would take up the impurity, enable a simple separation and recyclability. Polymer colloids with high affinity towards the drug, accessible porosity, high surface area and stimuli-responsive properties would be candidates, but such a complex system does not exist. Here, porous vinyl-functionalized organosilica nanoparticles prepared from a styrene bridged sol-gel precursor act as monomers. Initiation of the polymerization at the pore-walls and addition of functional monomers result in a special copolymer, which is covalently linked to the surface and covers it. An orthogonal modification of external surface was done by click attachment of a thermoresponsive polymer. The final core-shell system is able to remove quantitatively hydrophobic molecules such as the hormone progesterone from water. A change of temperature closes the pores and induces the aggregation of the particles. After separation one can reopen the particles and recycle them.publishe

Activatable Multizone Hybrid Hydrogels Containing Porous Organosilica Nanoparticles as Gatekeepers

Because the supply of clean water is one of the biggest challenges that we already face today, it is becoming increasingly important to develop smart strategies to purify sewage. Every wastewater is different and typically contains a large number of different contaminations. Adsorbents with a high surface area represent a powerful way to remove such compounds from a liquid. But, there are also several problems. An unselective adsorbent will bind everything and thus become a hazardous waste itself. If the adsorbent is selective, then several adsorbents are needed to treat the wastewater and achieve sufficient purification. The idea of the current paper is to develop a material that is capable of the uptake of different contaminants from a mixture; it then automatically separates in a multizone-structure. The impurities can be removed separately, step by step, by recycling the materials. Porous vinyl-functionalized organosilica nanoparticles are the key to creating the required anisotropy in selectivity when used as cross-linkers in hydrogels formed by a thermoresponsive polymer. The tailor-made functionalization of the pore surfaces allows for precise tuning of the host−guest interactions. It is shown that the presence of porous particles is a crucial factor for mass transport. The distance between them can be controlled by temperature-induced switching of the polymer from the swollen to the collapsed state. The smaller the distance between the porous particles, the more interparticle mass transport occurs. The correlating active pump effect, in combination with the multizone structure, allows switching separation on and off. The materials presented herein can be considered to be a model for a new generation of chromatography materials with variable and externally controllable separation properties

Copolymerization of Mesoporous Styrene‐Bridged Organosilica Nanoparticles with Functional Monomers for the Stimuli‐Responsive Remediation of Water

For every mass product, there are problems associated with the resulting waste. Residues of hormones in urine cannot be removed sufficiently from wastewater, and this has undesired consequences. An ideal adsorbent would take up the impurity, enable a simple separation and recyclability. Polymer colloids with high affinity towards the drug, accessible porosity, high surface area and stimuli-responsive properties would be candidates, but such a complex system does not exist. Here, porous vinyl-functionalized organosilica nanoparticles prepared from a styrene bridged sol-gel precursor act as monomers. Initiation of the polymerization at the pore-walls and addition of functional monomers result in a special copolymer, which is covalently linked to the surface and covers it. An orthogonal modification of external surface was done by click attachment of a thermoresponsive polymer. The final core-shell system is able to remove quantitatively hydrophobic molecules such as the hormone progesterone from water. A change of temperature closes the pores and induces the aggregation of the particles. After separation one can reopen the particles and recycle them.publishe

Magneto-Adaptive Surfactants Showing Anti-Curie Behavior and Tunable Surface Tension as Porogens for Mesoporous Particles with 12-Fold Symmetry

Gaining external control over self-organization is of vital importance for future smart materials. Surfactants are extremely valuable for the synthesis of diverse nanomaterials. Their self-assembly is dictated by microphase separation, the hydrophobic effect, and head-group repulsion. It is desirable to supplement surfactants with an added mode of long-range and directional interaction. Magnetic forces are ideal, as they are not shielded in water. We report on surfactants with heads containing tightly bound transition-metal centers. The magnetic moment of the head was varied systematically while keeping shape and charge constant. Changes in the magnetic moment of the head led to notable differences in surface tension, aggregate size, and contact angle, which could also be altered by an external magnetic field. The most astonishing result was that the use of magnetic surfactants as structure-directing agents enabled the formation of porous solids with 12-fold rotational symmetry.publishe