Stimuli Responsiveness Research Articles

Transcriptional responses of durum wheat to chronic chromium exposure reveal candidate proteins involved in metal detoxification and compartmentalization

Chromium phytotoxicity results in relevant alterations to plant physiology, gene expression, and genomic DNA methylation at a transgenerational level. Herein, transcriptional responses of durum wheat (Triticum turgidum L.) to chronic chromium exposure were explored in roots and leaves by RNA-seq approach. Plants grown all the time in a hydroponic system supplemented with 2.5 and 10 µM hexavalent chromium were compared to unstressful control plants, assessing biomass and seed yield analyses after senescence. Then, transcriptomic analysis was performed with these plants kept under 10 µM chromium 50 days after the onset of exposure. The chromium concentrations used were considered the lowest dose sufficient to alter gene expression without impeding plant development, while the sampling time reflected the effects in the pre-harvest phase and long-lasting defense mechanisms. Root and leaf samples from plants kept under 10 µM chromium stress and from unstressful control plants were analyzed, generating 12 RNA-seq libraries. In total, 965 and 810 transcripts were found to be differentially expressed, respectively, in roots and leaves in response to 10 µM chromium stress. In roots, transcriptional changes were noted in the primary and secondary metabolism, redox homeostasis, protein modification, solute transport, nutrient uptake, and external stimuli responses. Meanwhile, the transcriptional changes in leaves were primarily found in the secondary metabolism, hormone-related pathways, chromatin modifications, cell division, protein modification and homeostasis, solute transport, and nutrient uptake. In particular, the metal uptake and translocation pathways were studied with greater emphasis to identify key proteins involved in chromium transport and compartmentalization. Furthermore, several genes involved in the biosynthesis of malate-derived organic acids, trace metal transport/detoxification/chelation, and vacuolar compartmentalization were linked to primary defense responses, and some of them were also associated with two putative gene clusters. Therefore, these genes and gene clusters are suggested as valuable biotechnological targets for future proof-of-concept studies aimed at genetic engineering of durum wheat to improve plant tolerance to chromium exposure.

Study on Preparation and Performance of Acid pH-Responsive Intelligent Self-Healing Coating.

In this paper, microcapsules with acidic pH stimulus responsiveness were prepared through a one-step in situ polymerization method and a layer-by-layer assembly method. The effects of factors such as chitosan (CS) concentration, polymerization time, polymerization process temperature, and the number of polymerization layers on the performance of microcapsules were explored, and microcapsules with optimal performance were prepared and added to the epoxy coating. The morphology and structure of the microcapsules were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, and zeta potential testing. The thermal stability and sustained release properties of the microcapsules were studied through thermogravimetric analysis and sustained release curve testing. Through scratch experiments, immersion experiments, salt spray experiments, and electrochemical impedance spectroscopy tests, the impact of the added amount of microcapsules on the self-healing performance and anti-corrosion performance of the coating in complex environments was explored. The results show that the optimal preparation process of acidic pH-responsive microcapsules requires that the concentration of chitosan is 2 mg/mL, the polymerization time of the polyelectrolyte layer is 8 h, the heating temperature during the polymerization process is 75 °C, and the number of polyelectrolyte layers is three. The prepared acidic pH-responsive microcapsules have good morphology, pH sensitivity, and thermal stability. The average particle size is approximately 203 μm, the drug loading rate reaches 59.74%, and the encapsulation rate reaches 63.99%. The optimal added amount of the acidic pH-responsive microcapsule coating is 15 wt%. The coating has a dual-trigger mechanism underlying it stimulus response capability and has an obvious stimulus response to acidic pH. It can inhibit corrosion in non-scratch areas, and its anti-corrosion ability is significantly stronger than that of epoxy coatings and ordinary self-healing coatings. The coating has a stronger repair effect and anti-corrosion ability when the environmental pH becomes acidic.

Influencing Factors and Stimulus-Sensitivity of Chitosan/Polymethacrylic Acid (CS/PMAA) Nanogels as Nanocarriers

ABSTRACT Nanogel, nanosized hydrogel, can contribute to biomedical and pharmaceutical, especially in drug delivery, due to its enthralling properties. Small size, large surface area, hydrophilicity, and stimulus responsiveness of nanogel ameliorate tissue penetration, drug loading capacity, and targeted drug delivery. The current study prepared nanosized, pH-sensitive, biocompatible, and stable chitosan/polymethacrylic acid (CS/PMAA) based nanogels using MBA as a crosslinker and APS as an initiator. FTIR confirmed the reaction between functional groups to synthesize nanogels sufficiently in a spherical shape, as affirmed by a FESEM. DLS data revealed nanosized particles with a size range of 70–170 nm and a range of 6–13 for polydispersity index (PDI). A study showed that 2% of MBA crosslinker is sufficient to achieve the desired crosslinking in 60 minutes reaction time (RT) with nanogel size ~ 92 nm. Increasing RT from 30 to 80 minutes during nanogel synthesis demonstrated a decrease in nanogel sizes from 186–73 nm. Synthesized nanogels have shown pH sensitivity (stimuli responsiveness) in acidic and alkaline mediums with an increase in particle size in pH-2 (~144 nm) and pH-8 (~280 nm) compared to intermediate pHs. The pH sensitivity of nanogels by changing the size per the suspended medium’s pH is crucial for prolonged systemic circulation and targeted drug delivery. Moreover, nanogels have shown good colloidal stability with zeta potential (ZP) +28 mv in acidic and −38 mv alkaline mediums. DSC and XRD results demonstrated thermal stability and amorphous morphology of nanogels, respectively. BET surface analysis revealed the surface area of nanogels in the range of 65–68 cm2/g with an average pore size of 28–32 nm. In-vitro cytotoxicity in the L-929 cell line by MTT assay established the cell viability (>70%) after 24 hours of incubation, substantiating the non-toxicity and biocompatibility of nanogels as nanocarriers for drug delivery.

Green Preparation of S, N Co-Doped Low-Dimensional C Nanoribbon/C Dot Composites and Their Optoelectronic Response Properties in the Visible and NIR Regions.

The green production of nanocomposites holds great potential for the development of new materials. Graphene is an important class of carbon-based materials. Despite its high carrier mobility, it has low light absorption and is a zero-bandgap material. In order to tune the bandgap and improve the light absorption, S, N co-doped low-dimensional C/C nanocomposites with polymer and graphene oxide nanoribbons (the graphene oxide nanoribbons were prepared by open zipping of carbon nanotubes in a previous study) were synthesized by one-pot carbonization through dimensional-interface and phase-interface tailoring of nanocomposites in this paper. The resulting C/C nanocomposites were coated on untreated A4 printing paper and the optoelectronic properties were investigated. The results showed that the S, N co-doped C/C nanoribbon/carbon dot hybrid exhibited enhanced photocurrent signals of the typical 650, 808, 980, and 1064 nm light sources and rapid interfacial charge transfer compared to the N-doped counterpart. These results can be attributed to the introduction of lone electron pairs of S, N elements, resulting in more transition energy and the defect passivation of carbon materials. In addition, the nanocomposite also exhibited some electrical switching response to the applied strain. The photophysical and doping mechanisms are discussed. This study provides a facile and green chemical approach to prepare hybrid materials with external stimuli response and multifunctionality. It provides some valuable information for the design of C/C functional nanocomposites through dimensional-interface and phase-interface tailoring and the interdisciplinary applications.

Stimuli‐Responsive Bio‐Based Surfactant‐Polymer Gels

Rheological structuring and tunability of surfactant solutions is a vital aspect of product formulation for pharmaceutical, cosmetic and consumer product applications. Sulfate-free anionic surfactants (amino acid-based or bio-based surfactants) do not tend to build adequate structure and exhibit slow response in the presence of zwitterionics and salts unlike their sulfate-based counterparts which are able to respond quickly to external stimuli (change in pH and electrolyte concentration) via the formation of worm-like micelles. We explored an alternate structuring approach to establishing stimuli responsiveness in a mixed sodium laurylglucosides hydroxypropyl sulfonate (SLHS)-based surfactant system, through engineered surfactant-polymer interactions. We report in this work that the interplay of hydrophobic and electrostatic interactions between the mixed system of SLHS and Cocamidopropyl Betaine (CAPB) with Carrageenan produces a synergistic increase from ∼103 to ∼106 mPa.s in viscosity of the overall system, giving rise to a structuring mechanism which is tunable and responsive to external stimuli- such as variation in pH or electrolyte levels. This finding may prove helpful to formulators in related fields for the development of sulfate-free formulations which impart a novel and differentiated consumer experience.

Construction of CO2‐based thermoplastic elastomer via combining aliphatic polycarbonate and polyamide: A multiblock copolymer PPC‐mb‐PA6

AbstractA CO2‐based thermoplastic elastomer, poly(propylene carbonate)‐multiblock‐polyamide6 (PPC‐mb‐PA6) copolymer, was constructed through coupling amorphous/soft PPC blocks with crystalline/hard PA6 blocks. The PPC‐mb‐PA6 copolymers with different block length pairs were designed and synthesized, and then fully characterized by structural, thermal, and mechanical analysis. The proton nuclear magnetic resonance (1H‐NMR), diffusion ordered spectroscopy (DOSY), heteronuclear multiple‐bond correlation (HMBC) and gel permeation chromatography (GPC) results confirm that the multiblock sequence structure of PPC‐mb‐PA6. The differential scanning calorimetry (DSC) tests show that all PPC‐mb‐PA6s possess melting points around 179–206°C. The thermal and mechanical analysis indicates improved service temperatures (T5% up to 270°C) and tensile strength ranging from 15.8 to 39.6 MPa with higher PA6 content. The dynamic mechanical analysis demonstrates excellent shape memory effect of PPC‐mb‐PA6 with thermal stimuli responsiveness derived from the micro phase separation between soft PPC and hard PA6 domains. And the characteristic strain fixity parameter (Rf) and deformation recovery rate (Rr) are 98% and 100%, respectively, which are comparable with other excellent shape memory polymers.

Electrically Conductive Peptide Fibers as Direct Electron Transfer Scaffolds for Enzymatic Electrocatalysis

Biology provides many sources of inspiration for synthetic and multi-functional nanomaterials. Naturally evolved proteins possess a range of unique functions and self-assembly behavior. Some of these have electron transport functions as part of metabolic processes. Their flexible design and potential for stimuli responsiveness make proteins ideal building blocks of bioelectronic interfaces. In biosensor and electrocatalysis applications, bioelectronic materials are designed to interconvert biological signals or processes into electronic signals and vice versa. In this work, we designed a peptide fiber structure that exhibits stimuli-responsive self-assembly and the capacity to transport electrical current over micrometer long distances. Hierarchically ordered nanofibers of α-helical coiled-coil peptides were assembled using a pH responsive structure ordering motif comprising of two neighboring lysine residues. Cryo-EM structures of these assemblies reveal a novel organization of α-helical peptides in a cross coiled coil arrangement that exhibits electrical conductivity. Both solid-state and solution-based electrochemical characterization show that these fibers are conductive. Single-fiber conductive AFM determined that the solid-state electrical conductivity is on a similar order of magnitude with conductive cytochrome filaments from bacteria. Solution deposited fiber films approximately doubled the electroactive surface area of the electrode, confirming their conductivity in aqueous environments. Furthermore, these fibers can be used as scaffolds for redox enzyme immobilization for electrochemical biosensing. Progress towards immobilized enzymatic devices will be discussed as well. This work further expands the field of stimuli-responsive and multifunctional nanomaterials by using peptide assemblies as structural supports for future implementation in bioelectronic and bioelectrochemical systems.

Stimuli-Responsive Chiral Cellulose Nanocrystals Based Self-Assemblies for Security Measures to Prevent Counterfeiting: A Review.

The proliferation of misleading information and counterfeit products in conjunction with technical progress presents substantial worldwide issues. To address the issue of counterfeiting, many tactics, such as the use of luminous anticounterfeiting systems, have been investigated. Nevertheless, traditional fluorescent compounds have a restricted effectiveness. Cellulose nanocrystals (CNCs), known for their renewable nature and outstanding qualities, present an excellent opportunity to develop intelligent, optically active materials formed due to their self-assembly behavior and stimuli response. CNCs and their derivatives-based self-assemblies allow for the creation of adaptable luminous materials that may be used to prevent counterfeiting. These materials integrate the photophysical characteristics of optically active components due to their stimuli-responsive behavior, enabling their use in fibers, labels, films, hydrogels, and inks. Despite substantial attention, existing materials frequently fall short of practical criteria due to limited knowledge and poor performance comparisons. This review aims to provide information on the latest developments in anticounterfeit materials based on stimuli-responsive CNCs and derivatives. It also includes the scope of artificial intelligence (AI) in the near future. It will emphasize the potential uses of these materials and encourage future investigation in this rapidly growing area of study.

Bending motion induced by near-infrared laser irradiation of polymer films made by UV-curable liquid crystalline monomer containing gold-coated fine particles

Polymer films made by UV-curable liquid crystalline (LC) monomer have both characters of the external stimulus responsiveness of LC and flexibility of polymer chains. Therefore, polymer film made by UV-curable LC monomer are expected as soft actuators. By incorporating photothermal conversion materials in polymer film, the macro shape of film can be controlled by light irradiation. In this study, a polymer film made by UV-curable LC monomer containing gold-coated fine particles was prepared and its bending motion induced by near-infrared laser irradiation was studied. When the film is irradiated with near-infrared laser, it bends. We also investigated the dependence of the concentration and distribution of gold-coated fine particles in the film, and irradiation time and intensity for the bending displacement.

Transcranial alternating current stimulation can modulate the blink reflex excitability. Effects of a 10- and 20-Hz tACS session on the blink reflex recovery cycle in healthy subjects.

The blink reflex excitability, assessed through paired electrical stimuli responses, has been modulated using traditional non-invasive neurostimulation techniques. Recently, transcranial Alternating Current Stimulation (tACS) emerged as a tool to modulate brain oscillations implicated in various motor, perceptual, and cognitive functions. This study aims to investigate the influence of 20-Hz and 10-Hz tACS sessions on the primary motor cortex and their impact on blink reflex excitability. Fifteen healthy volunteers underwent 10-min tACS sessions (intensity 1mA) with active/reference electrodes placed over C4/Pz, delivering 20-Hz, 10-Hz, and sham stimulation. The blink reflex recovery cycle (BRrc) was assessed using the R2 amplitude ratio at various interstimulus intervals (ISIs) before (T0), immediately after (T1), and 30min post-tACS (T2). Both 10-Hz and 20-Hz tACS sessions significantly increased R2 ratio at T1 (10-Hz: p = 0.02; 20-Hz: p < 0.001) and T2 (10-Hz: p = 0.01; 20-Hz: p < 0.001) compared to baseline (T0). Notably, 20-Hz tACS induced a significantly greater increase in blink reflex excitability compared to sham at both T1 (p = 0.04) and T2 (p < 0.001). This study demonstrates the modulatory effect of tACS on trigemino-facial reflex circuits, with a lasting impact on BRrc. Beta-band frequency tACS exhibited a more pronounced effect than alpha-band frequency, highlighting the influential role of beta-band oscillations in the motor cortex on blink reflex excitability modulation.

Rough and porous silica-modified fiber membranes decorated with oleic acid for ultra-high flux and pH-responsive oil/water separation

The design of fiber membranes with both ultra-high flux and pH-responsive oil/water separation is challenging but of great significance to environmental protection and human health. In this work, the pH-responsive fiber membranes were prepared by immersing the silica-modified polyacrylonitrile fiber substrates into oleic acid solution. The obtained membranes exhibited highly rough surface structures (Ra = 14.26 µm), large pore sizes (5.35 µm), high porosities (86.04%), and pH-responsive functional groups, respectively. The pH-responsive fiber membranes also had superhydrophobic surfaces and excellent selective separation for oil/water mixtures, for example, a trichloromethane permeation flux of 87,829 L m-2h-1 for immiscible oil/water separation, and a water permeation flux of 69,802 L m-2h-1 after turning the pH of water from 7 to 13. The above data were much higher than those of stimulus-responsive fiber membranes used for oil/water separation. In addition, the pH-responsive fiber membranes were also used for separating water-in-oil emulsions and oil-in-water emulsions, and achieved the highest separation flux of 15,120 L m-2h-1. This work provides a simple strategy for the preparation of a stimulus responsiveness and high-performance material that can be used in the direction of treating practical oily wastewater.

Optically Mediated Hydrogel-Based Ionic Diode.

Ionic diodes with environmentally modulated ion-rectifying characteristics have attracted much attention and show great promise in the construction of smart devices with environmental adaptability. One immediate challenge is to integrate stimuli responsiveness and ion rectification into one single ionic diode, which requires a close cooperation of chemical principles and device technologies. Herein, an ionic diode based on a photoresponsive hydrogel with optically mediated ion-rectifying performances is introduced. Relying on the photoresponsive concentration of proton in the hydrogel, the ionic current rectification can be prominently enhanced upon ultraviolet (UV) irradiation. A maximum ionic current rectification ratio of the optically mediated ionic diode about 4× 105 is achieved. Furthermore, the hydrogel-based diode can serve as an AND logic gate operated by UV light and voltage bias as two independent inputs. As a proof of concept, to use the optically mediated diode is achieved to modulate the feedback of a robot with logic behaviors. This work provides a novel and valuable strategy for designing functional hydrogel-based devices with the integration of stimuli-responsiveness and logic signal processing through chemical approaches.

Emulsion Stabilized by Biocompatible and Stimuli-Responsive Poly(N-vinylcaprolactam)-Based Microgels: Effects of Electrostatic Repulsion and Deformability on Emulsion Stability.

Microgels have been widely used for stabilizing emulsions due to their softness and stimulus responsiveness. Although ultrastable emulsions have been prepared by microgel nanoparticles, the role of electrostatic interactions on emulsion stability is still a controversial topic and further investigation of the effect of microgel deformability is required. In the present study, neutral poly(N-vinylcaprolactam) (PVCL) and charged poly(N-vinylcaprolactam)-co-methacrylic acid (P(VCL-co-MAA)) microgels were synthesized and further used as emulsifiers to stabilizing emulsion. The P(VCL-co-MAA) microgel has a swelling ratio larger than that of the PVCL microgel in water. The nanomechanical properties of the microgels in water were characterized by atomic force microscopy with using the tip of different radii. The result reveals that the P(VCL-co-MAA) microgel is more deformable than the PVCL counterpart. Stability tests of the emulsions showed that below the volume phase transition temperature (VPTT) of the microgels, both microgel types can stabilize the emulsions under various conditions. Unexpectedly, most of the emulsions still remain stable above the VPTT. Further increasing the temperature to 60 °C, P(VCL-co-MAA) microgel emulsions remained stable at a pH value above the pKa of MAA while the emulsion was unstable below the pKa. However, phase separation occurs in PVCL microgel-stabilized emulsions at 60 °C. These results demonstrate that electrostatic repulsion and deformability of the microgels can enhance the emulsion stability, providing insights into the rational design and preparation of ultrastable Pickering emulsions.

Multi Stimuli Responsive Dual Aggregation-Induced Emission and Photochromic Behavior of a Tetraphenyl Substituted Triphenylamine Derivative and its Application as Anti-counterfeiting Agent.

A multi-stimuli responsive tetraphenyl substituted tripehnylamine-based aggregation induced emissive (AIE) material coupled with spiropyran was prepared. Owing to the presence of AIE and photochromic moiety, the molecule exhibits emissive aggregates, photochromism, and acidochromism. The multiple stimuli sensitive behavior of the molecule was explored for anti-counterfeiting behavior on TLC plate and commercial banknotes. The fluorogenic and photogenic response under UV and visible light established the potential of the candidate as a new generation encryption material.

Dual-Temperature/pH-Sensitive Hydrogels with Excellent Strength and Toughness Crosslinked Using Three Crosslinking Methods.

Hydrogels are widely used as excellent drug carriers in the field of biomedicine. However, their application in medicine is limited by their poor mechanical properties and softness. To improve the mechanical properties of hydrogels, a novel triple-network amphiphilic hydrogel with three overlapping crosslinking methods using a one-pot free-radical polymerization was synthesized in this study. Temperature-sensitive and pH-sensitive monomers were incorporated into the hydrogel to confer stimulus responsiveness, making the hydrogel stimuli-responsive. The successful synthesis of the hydrogel was confirmed using techniques, such as proton nuclear magnetic resonance spectroscopy (1H NMR), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD). In order to compare and analyze the properties of physically crosslinked hydrogels, physically-chemically double-crosslinked hydrogels, and physically-chemically clicked triple-crosslinked hydrogels, various tests were conducted on the gels' morphology, swelling behavior, thermal stability, mechanical properties, and drug loading capacity. The results indicate that the triple-crosslinked hydrogel maintains low swelling, high mechanical strength, and good thermal stability while not significantly compromising its drug delivery capability.

Poly[2]catenane Gels Based on Sequential Assembly of Small Molecules†

Comprehensive SummaryPolycatenane gels have attracted extensive attention due to their high degree of freedom and mobility. However, the syntheses of poly[2]catenane gels reported to date all rely on the polymer as the backbone. Herein, we prepared poly[2]catenane gels based on entirely sequential assembly of small molecules. Monomer M1 with two unclosed rings was first prepared, which self‐assembled to form supramolecular polymers (SPs) via hydrogen bonding and π‐π interactions. Upon adding small molecule monomers M2 and M3 with aldehyde groups, ring closing of SPs occurred because the amino groups in the SPs reacted with M2 to form imine bonds. In addition, M3, which had twice the number of aldehyde groups as M2, enabled SPs to ring‐close, causing the proceeding of crosslinking process at the same time. Thus linear SPs were transformed into poly[2]catenane gel networks. Due to the presence of hydrogen bonds in the poly[2]catenane gel, the gel also possessed stimulus responsiveness and self‐healing properties.

Microstructure induction of quaternary ammonium chitosan microcapsules based on magnetic field and study of their aroma release

Traditional pressure-sensitive microcapsules used in textiles face challenges of insufficient environmental friendliness in the production process and uncontrollable fragrance release. To address this issue, this study utilized quaternary ammonium chitosan and silica as wall materials to develop a magnetic aromatic microcapsule. The microstructure of the microcapsules was controlled by magnetic field induction, and its evolution pattern was investigated. After magnetic field induction, the microcapsules exhibited a trend of evolving from spherical to asymmetrical shapes, accompanied by significant changes in mechanical properties. Asymmetrical microcapsules showed higher adhesion and lower stiffness. When applied to cotton textiles, the cotton textiles treated with asymmetrical microcapsules released 63.40 % of lavender essential oil after 200 friction cycles, representing an 11.3 % improvement in release efficiency compared to regular microcapsules, indicating better mechanical stimulus responsiveness. Additionally, in antibacterial tests, aromatic cotton exhibited a 96.52 % inhibition ratio against Escherichia coli. In summary, this study explores methods to adjust the mechanical properties of microcapsules and the relationship between mechanical properties and microstructure, providing a new approach for functional textiles.

Strategic design of a multifunctional urea-triphenylamine benzotriazole-based material

The search for multifunctional derivatives is of paramount importance in material science considering sustainability, practicality, and applicability. For this reason, this article presents a multifunctional benzotriazole derivative synthesized through rational design, showcasing its versatility across diverse applications. The tailored functionality of the compound enables it to serve in photonics as an optical waveguide, as smart material as stimuli responsiveness material, and as a gelator for drug crystallization in pharmaceuticals. This work underscores the power of rational design for organic synthesis in creating versatile materials with broad applicability.

Thermal stimuli response diphenylmethane diisocyanate‐based polyurethane elastomer via adjustable silicon‐induced distinctive microstructure

AbstractThe segment character of polyurethanes (PUs) determines the micromorphology and properties. The effective segment regulation can customize the favorable performance of PUs. Herein, silicon covalent‐modified polyurethanes (MPUs) were prepared by incorporating diphenylmethane diisocyanate (MDI) and diphenyl silanediol (DPSD) into PU molecules as hard segments via a two‐step method. Distinctive microphase separation structures from sheet morphology to radial sheet or withered flower‐like microdomain were formed by adjusting hydrogen bonding of hard segments and post‐treatment techniques. Thus, with the addition of DPSD in hard segments, the thermo‐optic responses for MPUs occurred due to the different microphase evolution under thermal effect. And with the further addition of DPSD, the effect of thermal stimuli on the transmittance gradually weakened. It was very clear that with increasing the temperature, the transmittance of MPUs showed a gradual increase owing to melting the microcrystals or destroying the ordered accumulation of hard segments. Meanwhile, the high mechanical properties were obtained, higher 15 times tensile strength and more than 100 times elastic modulus than those of pure PU as well as the excellent thermal stability. In sum, this study was of great significance for developing new functionalized PU materials.Highlights Polyurethanes were prepared by inducing modified silicon functionality. The distinctive microphase separation evolution of MPUs was found. Thermal stimuli responses showed a gradual decrease due to different structure. High mechanical properties and thermal stability were also obtained.

Modified Janus silica-based sheets stable stimulus-responsive Pickering emulsion: An excellent recycling platform for tandem reaction

To accommodate the advancement of green chemistry and further enhance hydrogen utilization efficiency and organic compound conversion in reactions, a smart Pickering emulsion stabilized by modified Janus silica particles was successfully prepared for the tandem reaction of ammonia borane hydrolysis and organic hydrogenation reduction. The emulsion has been confirmed to possess high stability and rapid stimulus responsiveness. The high stability and large oil-water interface area of Pickering emulsions, along with their low energy demulsification method, provide an excellent reaction platform and catalyst in situ recovery strategy for tandem reactions. Moreover, the anisotropy of Janus particles facilitates the progression of tandem reactions, mitigating the waste associated with "sacrifice" mechanisms and averting hydrogen loss. Experimental results demonstrate that even when the molar amount of hydrogen released from ammonia borane is comparable to that of organic compounds, organic compounds still achieve a conversion rate of 99 %, with a hydrogen utilization efficiency 3–4 times higher than that of conventional two-phase systems. By simply adjusting the pH, the catalyst can be recovered in situ for the next cycle. Even after 5 cycles, a high conversion rate of organic compounds is maintained.