Charge interaction-driven jamming of nanoparticle monolayers at the oil–water interface can be employed as a method to mold liquids into tailored stable 3D liquid objects. Here, 3D liquid objects are ...fabricated via a combination of biocompatible aqueous poly(vinyl sulfonic acid, sodium salt) solution and a colloidal dispersion of highly fluorescent organo-modified graphitic carbon nitride (g-C3N4) in edible sunflower oil. The as-formed liquid object shows stability in a broad pH range, as well as flexible pathways for efficient exchange of molecules at the liquid–liquid interphase, which allows for photodegradation of rhodamine B at the interface via visible light irradiation that also enables an encoding concept. The g-C3N4-based liquid objects point toward various applications, for example, all-liquid biphasic photocatalysis, artificial compartmentalized systems, liquid–liquid printing, or bioprinting.
The phase separation in aqueous solutions of a double-hydrophilic block copolymer (DHBC) at concentrations mimicking the crowded environment in cells and its performance as a potential protein ...purification system are investigated. Similar to processes of self-coacervation, the coexistence of aqueous polymer-rich and polymer-depleted microscopic phases is observed and the partitioning of various species in them is investigated. Whereas small molecules, poly(ethylene glycol), and dextran can moderately partition in both phases, proteins and DNA are strongly enriched in the polymer-depleted phase, offering a pathway for biomacromolecule purification. While aqueous two-phase systems based on a pair of polymers are also used for purification of biological material, DHBC has the remarkable advantage that the proteins and DNA segregate in the polymer-depleted phase, enhancing and facilitating purification. Future optimization of DHBC chemistry may offer higher partition efficiency and a way for large-scale applications.
The need for more sustainable products and processes has led to the use of new methodologies with low carbon footprints. In this work, an efficient tandem process is demonstrated for the liquid‐phase ...catalytic upgrading of lignocellulosic biomass‐derived γ‐valerolactone (GVL) with trioxane (Tx) to α‐methylene‐γ‐valerolactone (MeGVL) in flow system using Cs‐loaded hierarchical beta zeolites. The introduction of mesopores along with the presence of basic sites of mild strength leads to MeGVL productivity 20 times higher than with the bulk beta zeolite, reaching 0.325 mmol min−1 gcat−1 for the best‐performing catalyst, the highest value reported so far. This catalyst proves stable upon reuse in consecutive cycles, which is ascribed to the partial depletion of the basic sites. The obtained MeGVL is subjected to visible‐light‐induced polymerization, resulting in a final material with similar properties to the widely used poly(methyl) methacrylate.
Sustainable tandem flow process: α‐Methylene‐γ‐valerolactone (MeGVL) is synthesized from lignocellulosic biomass‐derived γ‐valerolactone (GVL) in the presence of trioxane (Tx) using tailored Cs‐loaded hierarchical beta zeolite catalysts (see figure). The obtained MeGVL is subjected to a visible‐light‐induced polymerization reaction, giving a final material with similar properties to poly(methyl) methacrylate.
Herein, an approach via combination of confined porous textures and reversible deactivation radical polymerization techniques is proposed to advance synthetic polymer chemistry, i.e., a connection of ...metal–organic frameworks (MOFs) and activators regenerated by electron transfer atom transfer radical polymerization (ARGET ATRP). Zn2(benzene-1,4-dicarboxylate)2(1,4-diazabicyclo2.2.2octane) Zn2(bdc)2(dabco) is utilized as a reaction environment for polymerization of various methacrylate monomers (methyl, ethyl, benzyl, and isobornyl methacrylate) in a confined nanochannel, resulting in polymers with control over dispersity, end functionalities, and tacticity with respect to distinct molecular size. To refine and reconsolidate the compartmentation effect on polymer regularity, initiator-functionalized Zn MOF was synthesized via cocrystallization with an initiator-functionalized ligand, 2-(2-bromo-2-methylpropanamido)-1,4-benzenedicarboxylate (Brbdc), in different ratios (10%, 20%, and 50%). Through the embedded initiator, surface-initiated ARGET ATRP was directly initiated from the walls of the nanochannels. The obtained polymers had a high molecular weight up to 392 000. Moreover, a significant improvement in end-group functionality and stereocontrol was observed, entailing polymers with obvious increments in isotacticity. The results highlight a combination of MOFs and ATRP that is a promising and universal methodology to prepare various polymers with high molecular weight exhibiting well-defined uniformity in chain length and microstructure as well as the preserved chain-end functionality.
A novel diblock copolymer consisting of poly(vinylferrocene) (PVFc) and poly(N,N‐diethylacrylamide) (PDEA) is synthesized via a combination of anionic and RAFT polymerization. The use of a novel ...route to hydroxyl‐end‐functionalized metallopolymers in anionic polymerization and subsequent esterification with a RAFT agent leads to a PVFc macro‐CTA (M¯n = 3800 g mol−1; Đ = 1.17). RAFT polymerization with DEA affords block copolymers as evidenced by 1H NMR spectroscopy as well as size exclusion chromatography (6400 ≤ M¯n≤ 33700 g mol−1; 1.31 ≤ Đ 1.28). Self‐assembly of the amphiphilic block copolymers in aqueous solution leads to micelles as shown via TEM. Importantly, the distinct thermo‐responsive and redox‐responsive character of the blocks is probed via dynamic light scattering and found to be individually and repeatedly addressable.
A combination of anionic and RAFT polymerization leads to novel dual‐stimuli‐responsive block copolymers. Amphiphilic poly(vinylferrocene)‐b‐poly(N,N‐diethylacrylamide) is obtained that forms micellar assemblies in water. Owing to the dual‐responsive block copolymer, individually addressable redox‐ and thermo‐responsive micellation is observed.
Extremely compressible hydrogels are fabricated in one pot via sulfonic‐acid‐modified graphitic carbon nitride (g‐CN‐AHPA) as a visible light photoinitiator and reinforcer. The hydrogels show unusual ...compressibility upon applied stress up to 12 MPa, presenting temporary physical deformation, and remain undamaged after stress removal despite their high water content (90 wt%). Cyclic compressibility proves the fatigue resistance of the covalently and electrostatically reinforced system that possesses tissue adhesive properties, shock resistance, cut resistance, and little to no toxicity.
Surface‐functionalized carbon nitride facilitates the formation of extremely compressible hydrogels that withstand forces up to 12 MPa. In addition, the hydrogels feature tissue adhesive properties, shock resistance, cut resistance and little to no toxicity.
Graphitic carbon nitride (gCN) has a broad range of promising applications, from energy harvesting and storage to sensing. However, most of the applications are still restricted due to gCN poor ...dispersibility and limited functional groups. Herein, a direct photografting of gCN using various polymer brushes with tailorable functionalities via UV photopolymerization at ambient conditions is demonstrated. The systematic study of polymer brush-functionalized gCN reveals that the polymerization did not alter the inherent structure of gCN. Compared to the pristine gCN, the gCN-polymer composites show good dispersibility in various solvents such as water, ethanol, and tetrahydrofuran (THF). Patterned polymer brushes on gCN can be realized by employing photomask and microcontact printing technology. The polymer brushes with incorporated silver nanoparticles (AgNPs) on gCN can act as a multifunctional recyclable active sensing layer for surface-enhanced Raman spectroscopy (SERS) detection and photocatalysis. This multifunctionality is shown in consecutive cycles of SERS and photocatalytic degradation processes that can be applied to in situ monitor pollutants, such as dyes or pharmaceutical waste, with high chemical sensitivity as well as to water remediation. This dual functionality provides a significant advantage to our AgNPs/polymer-gCN with regard to state-of-the-art systems reported so far that only allow SERS pollutant detection but not their decomposition. These results may provide a new methodology for the covalent functionalization of gCN and may enable new applications in the field of catalysis, biosensors, and, most interestingly, environmental remediation.
Slide-ring (SR) gels have been fabricated through a convenient one-pot approach using thiol–ene click chemistry. Pseudo-polyrotaxanes of monothiolated β-cyclodextrin threaded on poly(allyl glycidyl ...ether)-block-poly(ethylene glycol)-block-poly(allyl glycidyl ether) were prepared in water by sonication and subsequently photo-cross-linked by UV irradiation. The pseudo-polyrotaxanes were characterized through dynamic light scattering analysis and nuclear Overhauser enhancement spectroscopy with the chemical and physical properties of the resulting SR gels being compared to the corresponding covalent gels. In contrast to these covalent gels, the SR gels showed comparable elasticity but exhibited high stretchability and tunable degradability under acidic conditions. We believe this simple and efficient fabrication method will expand and facilitate future applications of SR gels.
PDF
