Responsive Polymer Research Articles

Hydrophobic Domain Modulation of Chemical Responsiveness in a Bolaamphiphile-Based Supramolecular Monomer.

Self-immolative chemistries that respond in an irreversible manner to external stimuli are highly attractive to permanently degrade filamentous supramolecular biomaterials. Within the monomer, a balance needs to be struck between its capacity to be supramolecularly polymerized and degraded at an appropriate rate for a given application. Herein, we unravel the structure-property-function relationships of a library of squaramide-based bolaamphiphiles bearing a central disulfide-based self-immolative spacer to construct supramolecular polymers responsive to chemical stimuli in aqueous solutions. We examine the impact of changing the alkyl domain length (2 to 12 methylene units) on the formation of supramolecular filaments and their rate of degradation in response to a biological antioxidant, glutathione. A minimum of an octyl spacer is required to robustly form supramolecular polymers that can be irreversibly degraded through a cyclization-elimination reaction of the self-immolative spacer triggered by thiol-disulfide exchange. Further increasing the peripheral alkyl chain length to a decyl spacer increases the ordered packing of the amphiphiles, hindering their chemical degradation. This study provides a framework to design chemically responsive filamentous supramolecular polymers based on bolaamphiphiles that can be irreversibly degraded in aqueous solutions for their eventual application as biomedical materials.

Scattering-Free and Fast Response Polymer Brush-Stabilized Liquid Crystals Beam Steering Using Surface-Initiated Polymerization Technique.

Nonmechanical fast response optical beam steering technology is increasingly essential for telecommunications, imaging systems, optical sensing, displays, and military applications. Polymer network liquid crystal (PNLC) beam steering can achieve submillisecond response times but faces limitations due to scattering issues arising from the refractive index mismatch between the polymer network and the liquid crystals (LCs). In this article, we demonstrate a scattering-free, fast-response LC beam steering by using polymer brushes to stabilize the gradient refractive index. First, the initiator is incorporated into the alignment layer and the monomer is mixed into the LC layer. Surface-initiated polymerization (SIP) is then employed to grow the polymer brushes exclusively on the substrate's surface, thus confining the polymer network's growth to the LC bulk and reducing interfacial scattering. For polymer brush stabilized liquid crystal (PBSLC) beam steering device with a period size of 225 μm and a cell gap of 7.2 μm, the average transmission rate reaches 88% in the visible light spectrum with a haze value of only 6.91. The steering angle is 0.16, and the diffraction efficiency is 80.3%. When a voltage of 35 Vrms is applied, the primary energy can be tuned to the zeroth order, with a response time close to 1 ms. By cascading two PBSLC beam steering devices with opposite steering directions, the primary energy of the beam can be adjusted between zeroth, +1, and -1 order. This method requires only a UV light source, a precision displacement stage, a power supply, and a mask, avoiding the need for expensive equipment and complex electrode fabrication. By adjustment of the phase change period, step width, and number of steps during fabrication, the steering angles and diffraction efficiency of the PBSLC beam steering device can be easily controlled, highlighting its significant potential for industrial production.

Superparamagnetic iron oxide nanoparticles functionalized with on-demand redox-responsive contractible coordination polymer brush as molecular actuator driven by π-dimerization

Nanomachines require molecular actuators to be coupled to a condensed phase. In this work, a redox responsive 1D contractible coordination polymer (ZnL) used as non-interlocked actuator is grafted onto superparamagnetic iron oxide nanoparticles (SPIONs) in a brush-like configuration. Oxidized rod-like ZnL oligomers have ability to reversibly self-fold upon reduction via π-dimerization of their bis-viologen units. Unlike in usual responsive brushes, ZnL chains behave individually, generating spatially controlled mechanical motion at nanoparticle surface associated to significant variations of particle diameters. ZnL oligomers were “grafted to” SPIONs in a single step. Reduction of colloidal dispersions was perform by visible light illumination with the help of a photoreductant. π-dimerization was assessed by UV–vis–NIR and reversible contraction of ZnL brush was characterized by DLS. Effects of ZnL chains length and grafting density on mechanism and performance of contractibility were studied. ZnL brush can alternately be contracted and extended with excellent reversibility. Combined UV–vis–NIR, DLS and TGA analyses demonstrate that π-dimerization is only intramolecular and that chains behave as independent actuators. Maximal contraction of 22 nm is obtained for largest particles (DH = 86 nm). Full to partial contraction of the brush depends on grafting density with a threshold at ≈ 47 chains per particle.

Thermoresponsive and Supramolecular Polymers: Interesting Biomaterials for Drug Delivery.

How to use and deliver drugs to diseased and damaged areas has been one of the main concerns of pharmacologists and doctors for a long time. With the efforts of researchers, the advancement of technology, and the involvement of engineering in the health field, diverse and promising approaches have been studied and used to achieve this goal. A better understanding of biomaterials and the ability of production equipment led researchers to offer new drug delivery systems to the world. In recent decades, responsive polymers (exclusively to temperature and pH) and supramolecular polymers have received much attention due to their unique capabilities. Although this field of research still needs to be scrutinized and studied more, their recognition, examination, and use as drug delivery systems is a start for a promising future. This review study, focusing on temperature-responsive and supramolecular biomaterials and their application as drug delivery systems, deals with their structure, properties, and role in the noninvasive and effective delivery of medicinal agents.

Impregnation, dehydration and crosslinking of responsive organoboron polymer to generate smart gating membrane for multimolecular gradient separation

Responsive materials have garnered increasing attention in the membrane separation field. However, fabricating smart gating membranes with tunable pore sizes to separate complex systems remains challenging. Herein, gating membranes with boroxine skeleton and temperature-tunable pores were successfully fabricated by fixing lower critical solution temperature (LCST)-type organoboron polymers (poly(N-isopropylacrylamide-co-glycidyl methacrylate/3-aminophenylboronic acid), PNG-APBA) onto the membrane surface via "impregnation-dehydration-crosslinking" strategy. The conformational behavior of the NIPAM-containing polymer chains (shrinking above LCST-stretching below LCST) serves as a functional gate, enabling the membranes to achieve reversibly tunable pore sizes and surface properties. The modified membranes exhibit gradient separation capabilities for small/medium/large molecules in complex polymer systems through temperature-tunable channels. The tunable pores also provided a potential tool for the high-selectivity separation of mixed proteins, such as lysozyme (LZM) and hemoglobin (Hb). Notably, the conformational behavior of the polymer chains endowed the membranes with excellent self-cleaning ability (FRR> 99.5%), while the boroxine network enhanced the grafting stability of the polymer chains, ensuring effective reversibility and repeatability of membranes.

PH- and temperature-dual responsive polymer emulsion for rapid release of drag reducer

Slick water fracturing fluid is widely used in major oil fields due to its low cost and high drag reduction. Polyacrylamide emulsions drag reducers play a decisive role in slick water fracturing. The dissolution rate of polymer emulsions drag reducers was increased by adding hydrophilic surfactants, but the stability of the emulsions is poor, which limits its wide application. In order to solve the contradiction between the stability of polymer emulsion and rapid release of drag reducer. Here, a P(AA-AM-AMPS) polymer emulsion drag reducer with dual stimulation response of pH and temperature was designed. Surfactant (D400/OA) with dual responses to pH and temperature is synthesized by using oleic acid (HOA) and polyether amine 400 (D400). D400/OA shows a remarkable pH- and temperature-responsive behavior due to the pH- and temperature-induced structural transformation of D400/OA. Interestingly, D400/OA-stabilized monomer emulsion exhibits an obvious pH- and temperature-induced structural transformation. Meanwhile, The D400/OA-stabilized monomer emulsion has remarkable stability, which benefits the inverse emulsion polymerization of P(AM-AA-AMPS) polymer. The obtained P(AM-AA-AMPS) polymer emulsion maintain stability whose particle size nearly unchanged by storing for 15 days. Interestingly, P(AM-AA-AMPS) polymer emulsion can be released completely by changing the pH or temperature of the aqueous solution. The apparent viscosity of P(AM-AA-AMPS) polymer, in either the alkaline (pH=10.31) solution of 25±2 °C or neutral (pH=7) solution of 70±2 °C, respectively required 40 s and 8 min to reached a maximum value of 96 mPa·s. The release rate of P(AM-AA-AMPS) polymer emulsion is further enhanced under the dual responsive of temperature (70±2 ℃) and pH (10.31) and it takes only 20 s, In addition, the drag reduction rate of P(AM-AA-AMPS) polymer emulsion is 72 % when completely released under the dual responsive of temperature and pH, showing a remarkable drag reduction property. The D400/OA-stabilized P(AM-AA-AMPS) polymer emulsion are expected to meet the demand for the production enhancement of the oil and gas reservoirs.

Imparting insoluble-soluble property to Cyt c by immobilizing Cyt c in UCST-pH dual responsive polymer for highly sensitive detection of phenol

Immobilization of enzymes in porous organic framework (POF) materials is popular strategy to stabilize enzymes. For such solid enzyme catalysis system, improving the catalytic efficiency is challenging due to the diffusion resistance from solid-liquid interface and inner pores. Here, UCST-pH dual responsive polymeric carrier (PEG-b-PAAm-b-P(GMA-co-AAc)) was synthesized to immobilize cytochrome c (Cyt c), which impart the reversibly insoluble-soluble property to the immobilized Cyt c. The PEG-b-PAAm-b-P(GMA-co-AAc) could serve as an insoluble-soluble matrix to fast and efficiently immobilize Cyt c via covalent attachment, achieving a remarkable 92% loading efficiency within just 120min. The obtained insoluble PEG-b-PAAm-b-P(GMA-co-AAc)-Cyt c micelles exhibited an improvement in thermal, pH stability and reusability. The completely soluble PEG-b-PAAm-b-P(GMA-co-AAc)-Cyt c conjugates accelerated substrate diffusion and enhanced the catalytic efficiency. These excellent advantages led to low detection limit (1.99μM), lower than the presently reported biosensors based on enzyme mimics in the colorimetric detection of phenol. This UCST-pH dual responsive window presents a new platform to efficiently control the immobilization and release of enzymes, which will achieve excellent stability and catalytic efficiency.

Degradable polyolefins prepared by integration of disulfides into metathesis polymerizations with 3,6-dihydro-1,2-dithiine.

Disulfide-containing polyolefins were synthesized by ring-opening metathesis polymerization (ROMP) of the 6-membered disulfide-containing cyclic olefin, 3,6-dihydro-1,2-dithiine, which was prepared by ring-closing metathesis of diallyl disulfide. This approach facilitated the production of disulfide-containing unsaturated polyolefins as copolymers with disulfide monomer units embedded within a poly(cyclooctene) or poly(norbornene) framework. The incorporation of disulfides into the polymer backbone imparts redox responsiveness and enables polymer degradation via chemical reduction or thiol-disulfide exchange. This ROMP copolymerization strategy yielded both linear polyolefins, as well as bottlebrush polymers, with degradable segments, thereby broadening the scope of responsive polymer architectures synthesized by ROMP.

Active Control of Properties of Fresh and Hardening Concrete

Concrete mixtures have an optimized mix design in view of attaining desired properties. However, after mixing, during further processing, it is typically not possible to further adjust the performance of the fresh and hardening concrete. A new and emerging approach is to actively control the concrete properties by means of responsive particles or polymers triggered by an externally applied signal. Active control of properties of concrete refers to the concept of on- demand changes of one or more properties of the concrete after mixing by triggering a response to one or more of the constituents using a specific trigger signal (e.g. thermal, chemical, electrical, magnetic...). The on-demand control of properties can focus on the processing stage (including e.g. pumping, casting, 3D printing), the curing and hardening stage (including e.g. control of capillary pressure, shrinkage, setting, and hardening) and even on the hardened stage during service life (e.g. active corrosion control, active crack healing...). Addressing specific obstacles in cementitious environments, ensuring responsive material stability, controlling signal applicability, cost, logistics, and on-site safety is crucial for successful implementation. A RILEM technical committee has been initiated in 2023, working on the concept of Active Control of Properties of Concrete (RILEM TC 317-ACP). The committee will focus on active control of properties of fresh and hardening concrete. This paper gives a short introduction to scope and activities of TC 317-ACP.

Fluorescent, pH, and UCST Responsive Polymer Nanomaterials for Treatment of Recurrent Miscarriage.

Recurrent miscarriage (RM), defined as three or more consecutive spontaneous miscarriages, affects many women of childbearing age. The pathological basis of RM is an imbalance in apoptosis, with the MDM2-p53 pathway playing a crucial role. In this study, we synthesized poly(6-acetoxyl-ε-caprolactone)-graft-(4-amino-benzimidazole) (PCCL-4-ABI) by modifying poly(6-acetoxyl-ε-caprolactone) (PCCL) with 4-amino-benzimidazole (4-ABI). The introduction of carboxyl and 4-ABI groups endowed the PCL backbone with fluorescence, pH responsiveness, and UCST responsiveness. The temperature-dependent release behavior of compound 1-loaded PCCL-4-ABI nanofluorescent materials was attributed to UCST transition. We successfully developed a novel nanofluorescent polymer drug delivery platform, PCCL-4-ABI@1, and evaluated its regulatory effects on p53 and MDM2 in trophoblast cells (HTR-8/SVneo). The results showed that the system loaded with low molecular weight heparin increased MDM2 and decreased p53 expression in a dose-dependent manner, thereby inhibiting trophoblast cell apoptosis. This study developed a biodegradable poly(ε-caprolactone) with UCST behavior, significant for the advancement of thermoresponsive fluorescent nanoparticle systems.

Efficient Encapsulation of β-Lapachone into Self-Immolative Polymer Nanoparticles for Cyclic Amplification of Intracellular Reactive Oxygen Species Stress.

The selective upregulation of intracellular oxidative stress in cancer cells presents a promising approach for effective cancer treatment. In this study, we report the integration of enzyme catalytic amplification and chemical amplification reactions in β-lapachone (Lap)-loaded micellar nanoparticles (NPs), which are self-assembled from reactive oxygen species (ROS)-responsive self-immolative polymers (SIPs). This integration enables cyclic amplification of intracellular oxidative stress in cancer cells. Specifically, we have developed ROS-responsive SIPs with phenylboronic ester triggering motifs and hexafluoroisopropanol moieties in the side chains, significantly enhancing Lap loading efficiency (98%) and loading capacity (33%) through multiple noncovalent interactions. Upon ROS activation in tumor cells, the Lap-loaded micellar NPs disassemble, releasing Lap and generating additional ROS via enzyme catalytic amplification. This process elevates intracellular oxidative stress and triggers polymer depolymerization in a positive feedback loop. Furthermore, the degradation of SIPs via chemical amplification produces azaquinone methide intermediates, which consume intracellular thiol-related substrates, disrupt intracellular redox hemostasis, further intensify oxidative stress, and promote cancer cell apoptosis. This work introduces a strategy to enhance intracellular oxidative stress by combining enzymatic and chemical amplification reactions, providing a potential pathway for the development of highly efficient anticancer agents.

A New Class of Mechano-Responsive PolyureThane Via Anthracene -TAD Diels-Alder (DA) Click Chemistry.

Smart or stimuli-responsive polymers have garnered significant interest in the scientific community due to their response to different stimuli like pH, temperature, light, mechanical force, etc. Mechanophoric polymer is an intriguing class of smart polymers that respond to external mechanical force by producing fluorescent moieties and can be utilized for damage detection and stress-sensing assessment. In recent reports on mechanophoric polymers, different mechanophoric motifs such as spiropyran, rhodamine, coumarin, etc. are explored. This investigation reports a new kind of mechanophoric polyurethane (PU) adduct based on Diels-Alder (DA) click chemistry. Here, an anthracene(An)-end capped tri-armed urethane system is synthesized, followed by a DA reaction using bis-(1,2,4-triazoline-3,5-dione) (bis-TAD) derivative. The incorporation of bis-TAD in the urethane system renders the anthracene inactive ("turn-off") by dismantling its conjugation as a result of a successful DA reaction. The soft PU translated into a harder material through bis-TAD linkages between polymer chains as evident from nanoindentation (NINT) analysis. The resulting material reverts back to its fluorescent "turned-on" mode owing to a force-accelerated retro-Diels-Alder (r-DA) reaction. Besides the mechanophoric attributes, the material demonstrates self-healing behavior examined by microscopic investigations. This innovative approach can be a potential route to design responsive polymers with dynamic functionalities for advanced material applications.

Photorheologic Silicone Composites with Adaptive Properties by Utilizing Light‐Degradable Organosilica Nanoparticles as Fillers

AbstractImplementing inorganic filler particles is a powerful method for improving the mechanical properties of polymer composites. The physical properties are determined by the interaction of the filler with the polymer. Thus, factors like the surface‐to‐volume ratio and surface modification are important. Besides the strategies of influencing these physical properties by a prior modification of the filler, this approach applies a post‐treatment of the composite. The present publication focuses on bringing stimuli‐responsive properties to a composite material by changing the chemical composition and structure of the filler particles. Instead of creating a responsive polymer, the concept is to use photo‐degradable organosilica nanoparticles that can change the mechanical properties of a polymer/filler composite after it has been prepared. After the synthesis of nitrobenzyl ether containing organosilica nanoparticles and the investigation of the photochemical processes, the preparation of the composites with silicones is described. Vinyl groups are attached to the surfaces to secure a homogeneous distribution of the filler particles inside the polymer matrix. After light‐induced decomposition, the mechanical properties are investigated. Other than expected, the material becomes stiffer, which is explained by an increase in the surface area of the silica particles, accompanied by the emergence of hydroxy groups that interact with the polysiloxane.

Competence of Carbonaceous Fibers/Nanofillers (Graphene, Carbon Nanotube) Reinforced Shape Memory Composites/Nanocomposites Towards Aerospace—Existent Status and Expansions

Abstract Shape memory or stimuli responsive polymers have established a unique grouping of smart materials. The technical merit of these polymers has been evaluated in aerospace sector, since last few decades. Particularly, the stimuli responsive polymers render inherent competences to recuperate the structural damages in exterior/interior space architectures. In this context, both the thermoplastics as well as thermosetting polymers depicted essential stimuli responsive behaviour. As interpreted in this state-of the-art review, the carbonaceous reinforcement like carbon fibers and nano-reinforcements including nanocarbons (graphene, carbon nanotube) have been employed in the shape recovering matrices. The performance of ensuing shape retrieving aerospace materials was seemed to be reliant on the polymer chain crosslinking effects, filler/nanofiller dispersal/alignment, microstructural specs, interfacial contour and interactions, and processing techniques used. Consequently, the shape actuations of polymer/carbon fiber composites were found to be instigated and upgraded through the inclusion of nanocarbon nano-additives. The ensuing high-tech shape memory composites/nanocomposites have anomalous significance for various aero-structural units (fuselage, wings, antennas, engines, etc.) due to prevention of possible thermal/shock/impact damages. Future implications of carbonaceous shape memory composites/nanocomposites in aerospace demands minimizing the structure-property-performance challenges and large scale fabrication for industrial scale utilizations. In this way, deployment of carbonaceous nanofiller/filler based composites revealed enormous worth due to low density, anti-fatigue/wear, anti-corrosion, non-flammability, self-healing, and extended durability and long life operations. However, there are certain challenges associated with the use of nanocarbons and ensuing nanocomposites in this field markedly the adoption of appropriate carbon fiber coating technique, aggregation aptitude of nanocarbons, additional processing steps/cost, nanoparticle initiated invisible defects/voids, difficulty in machinability operations due to presence of nanoparticles, and corrosion risk of composite structures in contact with metal surfaces. By overcoming these hinderances, nanoparticles modified carbon fiber based composites can be promising towards a new look of upcoming modernized aerospace industry.

Ionized copolyesters with pH-responsive degradability: Accelerated degradation in specific environments

The development of environmentally responsive biodegradable polymers is a promising solution for balancing the stability and degradability of biodegradable plastics. In this study, a commercial biodegradable polyester, poly(butylene adipate-co-butylene terephthalate) (PBAT), was used as the substrate and was synthetically modified with a small amount of anionic sodium 1–3-isophthalate-5-sulfonate (SIPA) to obtain the ionized random poly(butylene adipate-co-butylene terephthalate-co-butylene 5-sodiosulfoisophthalate) (PBATS). The introduction of the sodium sulfonate ionic group enhanced the mechanical and heat-resistant properties of the material, while significantly improving the hydrophilicity and water absorption of the copolyesters of PBATSs and endowing them with special pH-responsive degradation properties. Compared with PBAT, PBATS copolyesters could accelerate degradation in acidic or alkaline buffer solutions and natural seawater, while degradation was inhibited in neutral buffer solutions at pH 7.2. Degradation experiments in simulated gastric, intestinal, and body fluids revealed that the copolyester showed specific and rapid degradation in acidic gastric fluids. This environmentally-responsive degradable material greatly expands the special applications of biodegradable polyesters in the fields of environmental remediation and medical applications.

Mechanochromic Displays Based on Photoswitchable Cholesteric Liquid Crystal Elastomers

Stimuli responsive optical materials are attractive for many areas, from healthcare to art design. However, creating intricate color‐changing patterns for visual information is still a challenge. This work describes the preparation of mechanochromic structural colored intricate pictures imprinted in cholesteric liquid crystal elastomers by using a chiral isosorbide molecular photo‐switch. The photo‐switch contains a photoisomerizable cinnamate moiety and was incorporated in a main chain liquid crystal oligomer with photopolymerizable acrylate end groups. After coating, the structural colored film was irradiated with ultraviolet (UV) light in air causing E/Z isomerization of the cinnamate units leading to a redshift of the structural color of the film. A grayscale photomask was used to spatially control the photoisomerization reaction and imprint colorful pictures such as portraits and landscapes, in the cholesteric liquid crystal films with high resolution. Photopolymerization in a nitrogen atmosphere led to a mechanochromic cholesteric liquid crystal elastomer with striking structural colors that blueshift upon strain independently. The sharp details of the patterns were preserved even under deformation and the system returned to the initial state upon strain removal. Our work offers a simple photo‐switch approach to prepare stimuli responsive optical polymers imprinted with color‐changing pictures of unprecedented complexity.

Mechanochromic Displays Based on Photoswitchable Cholesteric Liquid Crystal Elastomers.

Stimuli responsive optical materials are attractive for many areas, from healthcare to art design. However, creating intricate color-changing patterns for visual information is still a challenge. This work describes the preparation of mechanochromic structural colored intricate pictures imprinted in cholesteric liquid crystal elastomers by using a chiral isosorbide molecular photo-switch. The photo-switch contains a photoisomerizable cinnamate moiety and was incorporated in a main chain liquid crystal oligomer with photopolymerizable acrylate end groups. After coating, the structural colored film was irradiated with ultraviolet (UV) light in air causing E/Z isomerization of the cinnamate units leading to a redshift of the structural color of the film. A grayscale photomask was used to spatially control the photoisomerization reaction and imprint colorful pictures such as portraits and landscapes, in the cholesteric liquid crystal films with high resolution. Photopolymerization in a nitrogen atmosphere led to a mechanochromic cholesteric liquid crystal elastomer with striking structural colors that blueshift upon strain independently. The sharp details of the patterns were preserved even under deformation and the system returned to the initial state upon strain removal. Our work offers a simple photo-switch approach to prepare stimuli responsive optical polymers imprinted with color-changing pictures of unprecedented complexity.

Benjamin McDonald.

"A turning point in my career was exploring the molecular design of responsive polymers and macromolecular materials as a postdoctoral scholar… My group has fun by laughing, both in lab and group meeting, as well going on fun outings like group cookouts on the beach…" Find out more about Benjamin McDonald in his Introducing… Profile.

Analysis of Structural Changes of pH-Thermo-Responsive Nanoparticles in Polymeric Hydrogels.

The pH- and thermo-responsive behavior of polymeric hydrogels MC-co-MA have been studied in detail using dynamic light scattering DLS, scanning electron microscopy SEM, nuclear magnetic resonance (1H NMR) and rheology to evaluate the conformational changes, swelling-shrinkage, stability, the ability to flow and the diffusion process of nanoparticles at several temperatures. Furthermore, polymeric systems functionalized with acrylic acid MC and acrylamide MA were subjected to a titration process with a calcium chloride CaCl2 solution to analyze its effect on the average particle diameter Dz, polymer structure and the intra- and intermolecular interactions in order to provide a responsive polymer network that can be used as a possible nanocarrier for drug delivery with several benefits. The results confirmed that the structural changes in the sensitive hydrogels are highly dependent on the corresponding critical solution temperature CST of the carboxylic (-COOH) and amide (-CONH2) functional groups and the influence of calcium ions Ca2+ on the formation or breaking of hydrogen bonds, as well as the decrease in electrostatic repulsions generated between the polymer chains contributing to a particle agglomeration phenomenon. The temperature leads to a re-arrangement of the polymer chains, affecting the viscoelastic properties of the hydrogels. In addition, the diffusion coefficients D of nanoparticles were evaluated, showing a closeness among with the morphology, shape, size and temperature, resulting in slower diffusions for larger particles size and, conversely, the diffusion in the medium increasing as the polymer size is reduced. Therefore, the hydrogels exhibited a remarkable response to pH and temperature variations in the environment. During this research, the functionality and behavior of the polymeric nanoparticles were observed under different analysis conditions, which revealed notable structural changes and further demonstrated the nanoparticles promising high potential for drug delivery applications. Hence, these results have sparked significant interest in various scientific, industrial and technological fields.

Harnessing the Photoperformance of N-Methyl-Quinolinone for Gated Photo-Driven Cyclability and Reversible Photoligation.

[2π + 2π]-photocycloadditions and their ability to trigger controlled and reversible photoligation through disparate wavelengths provide an attractive platform to unlock advanced functionalities in soft materials. Yet, among the limited amount of functional motifs enabling reversible photoreactions, cyclability is often overlooked due to poor reaction yield and orthogonality. In this study, the advantageous photocharacteristics of the previously underexplored N-methyl-quinolinone photoresponsive motif are leveraged to create a covalent gated system, enabling controlled formation and cleavage of covalent bonds on demand. A systematic evaluation of individual cycloadditions and reversions on the molecular scale, including reaction rates, conversions, and photoproducts, allows identification of the required conditions for generating controlled photoreactions with a remarkable degree of cyclability; while, maintaining high reaction yields. Ultimately, these controlled and cyclable reactions are translated to a macromolecular scale, showcasing a comparable performance in initiating reversible photoligation, as observed at the molecular level. In addition, it is also shown that this progressive methodology can be leveraged to gain a comprehensive understanding of cyclability and clarify the factors contributing to its decreasing yield. Overall, unlocking the potential of quinolinone derivatives through this step-by-step approach lays the foundation for the development of highly controlled and responsive polymer materials with unprecedented potential.