Smart Polymer Research Articles

4D Printing: Research Focuses and Prospects

As an emerging technology in the field of additive manufacturing, 4D printing is highly disruptive to traditional manufacturing processes. Therefore, it is necessary to systematically summarize the research on 4D printing to promote the development of related industries and academic research. However, there is still an obvious gap in the visual connection between 4D printing theory and application research. We collected 2070 studies from 2013 on 4D printing from the core collection of Web of Science. We used VOSviewer 1.6.20 and CiteSpace software 6.3.3 to visualize the references and keywords to explore focuses and trends in 4D printing using scientometrics. In addition, real-world applications of 4D printing were analyzed based on the literature. The results showed that “tissue engineering applications” is the most prominent focus. In addition, “shape recovery”, “liquid crystal elastomer”, “future trends”, “bone tissue engineering”, “laser powder bed fusion”, “cervical spine”, “4D food printing”, “aesthetic planning” are also major focuses. From 2013 to 2015, focuses such as “shape memory polymers” and “composites” evolved into “fabrication”. From 2015 to 2018, the focus was on “technology” and “tissue engineering”. After 2018, “polylactic acid”, “cellulose”, and “regenerative medicine” became emerging focuses. Second, emerging focuses, such as polylactic acid and smart polymers, have begun to erupt and have become key research trends since 2022. “5D printing”, “stability” and “implants” may become emerging trends in the future. “4D + Food”, “4D + Cultural and Creative”, “4D + Life” and “4D + Clothing” may become future research trends. Third, 4D printing has been widely used in engineering manufacturing, biomedicine, food printing, cultural and creative life, and other fields. Strengthening basic research will greatly expand its applications in these fields and continuously increase the number of applicable fields.

Synthesis of a gallic acid-based self-healing waterborne polyurethane with a thermo-responsive dynamic phenol-carbamate network for enhanced mechanical strength, antimicrobial activity, and shape memory properties

To expedite the advancement of multifunctional next-generation smart materials, it is imperative to create polymers derived from renewable, green bio-based resources. This paper presents a direct synthesis of thermo-responsive aqueous polyurethanes by combining gallic acid (GA) with isocyanate groups to form a dynamic phenol-carbamate crosslinked network and the incorporation of the metal-organic framework Cu-MOF-2 for synergistic effects. The resulting GA-based polyurethane (MOF-GWPU) exhibits excellent thermal stability and mechanical properties, achieving an ideal balance between mechanical strength and self-healing efficiency. The MOF-GWPU film demonstrates strong antimicrobial efficacy against Escherichia coli and Staphylococcus aureus, highlighting its exceptional antibacterial performance. The thermo-responsive dynamic covalent bonds enable the MOF-GWPU film to rapidly revert from a temporary shape back to its original form. Post-processing experiments further indicate that the crosslinked GA-PU polymer can be efficiently recycled through solution casting and hot-pressing techniques. This design offers a novel approach and valuable insights for advancing the development of multifunctional smart polymers derived from bio-based resources.

Role of Sterilization on In Situ Gel-Forming Polymer Stability

In recent years, stimulus-sensitive drug delivery systems have been developed for parenteral administration as a depot system. In situ systems incorporate smart polymers that undergo a phase transition at the site of administration. All parenteral and ocular dosage forms must meet sterility requirements. Careful selection of the sterilization method is required for any type of stimuli-sensitive system. Current sterilization methods are capable of altering the conformation of polymers or APIs to a certain extent, ultimately causing the loss of pharmacological and technological properties of the drug. Unfortunately, the issues of risk assessment and resolution regarding the sterilization of stimuli-sensitive systems, along with ways to stabilize such compositions, are insufficiently described in the scientific literature to date. This review provides recommendations and approaches, formulated on the basis of published experimental data, that allow the effective management of risks arising during the development of in situ systems requiring sterility.

Optimization, experimental and theoretical investigation of modified guar-gum and poly(acrylic acid) based smart hydrogel for controlled release applications in the agricultural field

A series of smart polymer hydrogels with good uptake and controlled release characteristics were synthesized free-radically by growing poly(acrylic acid) on allylated guar gum using ammonium persulfate as an initiator and trimethylolpropane triacrylate as the crosslinker. The synthesized hydrogels were evaluated using FT-IR and NMR for their structure, thermo-gravimetric analysis (TG) to measure thermal stability, and scanning electron microscopy (SEM) to analyze surface morphology and swellability by gravimetric method under different pH and temperature conditions. The soil moisture content and gel fractions were measured using gravimetric methods. Additionally, a theoretical investigation was also performed to assess the urea-holding capacity of the synthesized hydrogel matrix using density functional theory (DFT) calculations. The uptake study revealed that the hydrogel with optimized monomer feed composition absorbed 851 g/g of water, 78 % and 67 % of urea from 0.5 % and 1 % urea solutions respectively under ambient conditions. The release study showed that 56 and 47 % of absorbed urea were released over 15 days from the urea-loaded hydrogels (0.5 % and 1 % urea solutions respectively). The uptake mechanism obeyed the non-Fickian and first-order kinetics models. The experimental evaluation and DFT calculations conveyed that the synthesized hydrogel could act as a candidature matrix for the controlled release of water and fertilizer in the agricultural field.

Delamination of MXene using biomolecule: An effective strategy toward the utilization of delaminated MXene as fillers in polymer composites

AbstractWith the emergence of two‐dimensional (2D) materials analogous to graphene, transition metal carbides and carbonitrides with unique desirable characteristics known as MXenes have turned out to be a hot research topic. Recent studies increasingly focus on the structure–property relationships of MXenes and their hybrid formations with other materials. The exfoliation and delamination of MXenes using various agents is gaining attention, while their application in functional composites presents another exciting research direction. However, the exfoliation of multi‐layered MXene into few‐layered nanosheets using bio‐based agents remains underexplored. In this study, tannic acid (TA) is employed as a bio‐exfoliating agent to delaminate Ti3C2Tx MXene, while optimizing the ratio of TA to achieve efficient exfoliation and dye adsorption. The MXene/TA composites demonstrated a maximum adsorption capacity of 187.264 mg/g and a removal efficiency of 93.69% for methylene blue (MB) in water, in accordance with the Langmuir isotherm model. Furthermore, MB adsorption caused MXene to coagulate into floccules, enabling easy removal via filtration. The study highlights the trifold role of tannic acid in MXene as a delaminating, antimicrobial, and adsorption‐enhancing agent, creating a multifunctional MXene‐tannic acid system. It introduces a new class of hybrid materials with effective applications in water purification. Additionally, incorporating this hybrid material into polymers can fine‐tune their properties, leveraging the synergistic effects of the trio to develop high‐performance smart polymer composites for diverse applications.Highlights Synthesis of MXene from Ti3C2Tx Optimization of the delamination efficiency of the biomolecule tannic acid Characterization of tannic acid‐MXene delaminated composites Analysis of the antibacterial efficiency of tannic acid delaminated MXene Investigation of water purification efficiency of delaminated MXene

Recent Advancement of Novel Drug Delivery Systems for Topical Anaesthesia Formulations

Abstract: In recent years, there have been exciting developments in improving how we deliver anaesthesia through the skin. Nanotechnology is a key player, using tiny particles to encapsulate and transport anaesthetic agents, ensuring a controlled and steady release. This helps overcome challenges like inconsistent absorption and short-lasting effects seen with traditional methods. Transdermal patches are gaining attention too; they release drugs slowly and steadily, eliminating the need for frequent reapplication while maintaining a constant drug level at the application site. Smart polymers are bringing innovation by responding to specific triggers, enabling on-demand drug release. This allows for personalized anaesthesia based on individual patient needs. In recent years, there have been exciting developments in improving how we deliver anaesthesia through the skin. Nanotechnology is a key player, using tiny particles to encapsulate and transport anaesthesia agents, ensuring a controlled and steady release. This helps overcome challenges like inconsistent absorption and other short-lasting effects seen with traditional methods. Microemulsion systems, made of water, oil, surfactants, and co-surfactants, are another promising approach. They enhance drug solubility and availability, providing a stable environment for including anaesthesia agents. Transdermal patches are gaining attention too; they release drugs slowly and steadily, eliminating the need for frequent reapplication and maintaining a constant drug level at the application site. Smart polymers are bringing innovation by responding to specific triggers, enabling on-demand drug release. This allows for personalized anaesthesia based on individual patient needs. Together, these advancements mark a significant shift towards more effective, patient-friendly, and personalized topical anaesthesia delivery systems.

Shape memory and shape recovery characterization of thermoplastic urethane

ABSTRACT Polyurethane shape memory polymer, as a smart material, has been becoming more and more popular due to its greater multifunctionality in various industrial and biomedical applications. Here, the authors reported the characterization, and comprehensive methodology and acquired the results of thermoplastic urethane (SMTPU) as a shape memory polymer, with 35°C as the glass transition temperature, by examining its creep. This smart polymer exhibits excellent shape memory behaviour due to its steady, chemically cross-linked network. Such behaviour of shape memory polymer determines its usability in various functional applications. Furthermore, the activation temperature range of SMPTPU is close to body temperature and room temperature as well, so it can be employed in more demanding industrial applications. Thus, it becomes essential to investigate the shape-changing/memory behaviour of commercial SMTPU. A quantitative analysis was done to determine the effects of programming temperature, maximum uniaxial strain, and compressive strain on shape memory characteristics viz. the shape recovery ratios and shape fixity ratios. Along with the excellent shape memory effect, this material also exhibits high creep and elasticity at room temperature, indicating that it may be used for various industrial and biomedical applications.

Supercapacitor electrodes based on Ru/RuO2 decorated on N,S-doped few-layer graphene

Innovatively designed flexible and high-performance shape memory polymer supercapacitors are promising next-generation energy storage devices for portable and wearable electronics. Therefore, thermally induced smart shape memory polymer polyurethane was synthesized using polycaprolactone/poly(ethylene glycol)/hexamethylene diisocyanate (PCL/PEG/HDI) in which the incorporation of PEG successfully assisted in lowering the transition temperature. The resulting polymer exhibits a remarkable transition temperature of 50 °C and a shape recovery ratio of 100 % at a strain of 300 %. The smart polymer was coated with a silver paste to ease the electron flow followed by coating with the electrode. Hybrid electrode materials are prepared in two stages. Initially, a few layers of holey-graphene were synthesized, where BET surface area reveals the presence of pores that are tuned by isothermal treatments in O2-atmosphere. Subsequently, active hybrid electrode materials nanostructured Ru/RuO2 decorated N, S-doped few layers of holey graphene were synthesized using hydrothermal methods. Here, nitrogen and sulfur doping in the basal or edge plane served as catalysts and metal coordination sites, facilitating the uniform distribution of ruthenium nanoparticles on the graphene. It is further confirmed by the density function theory (DFT) calculation using the adsorption energy. The optimized hybrid electrode material demonstrates a specific capacitance of 1297 mFcm−2 at a current density of 2 mAcm−2. A flexible-shape memory polymer supercapacitor exhibits a notable device-specific capacitance of 189 mFcm−2 at a current density of 1 mAcm−2, a high energy density of 45 µWhcm−2 at a power density of 0.25 mWcm−2, with 81 % of specific capacitance retention after eight shape programming and recovery cycle. Excellent shape recoverability and robust electrochemical performance make the as-fabricated symmetric supercapacitors a promising candidate for integration in flexible electronic applications.

Recent Advances and Future Prospects in Polymer-Mediated Drug Delivery Systems: A Comprehensive Review.

Polymer-based drug carriers have revolutionized the pharmaceutical landscape, providing innovative approaches for efficient drug delivery. These advanced systems have significantly mitigated traditional challenges, offering new avenues for targeted and controlled drug release. This paper aims to explore polymers, focusing on their classification, properties, drug release mechanisms, and pharmaceutical applications while emphasizing recent advancements and future prospects in the field. Polymers can be classified based on their origin, biodegradability, and physical properties. Their unique characteristics, such as biocompatibility, flexibility, and ability to modify surface properties, make them ideal for drug delivery applications. The review delves into various drug release mechanisms employed by polymer-based systems, including diffusion, degradation, swelling, and stimuli-responsive release. These mechanisms ensure a controlled and sustained release of therapeutic agents, enhancing efficacy and reducing side effects. The pharmaceutical applications of polymer-based drug carriers are vast, encompassing targeted delivery to specific tissues or cells, sustained-release formulations, and the delivery of complex molecules like proteins and nucleic acids. Despite their advantages, polymer-based drug delivery systems face limitations, including potential toxicity, stability issues, and manufacturing challenges. Addressing these limitations through continued research and development is crucial for advancing the field. Recent advancements, such as smart polymers and nanotechnology integration, hold promise for overcoming these challenges and improving drug delivery efficiency. In conclusion, polymer-mediated drug delivery systems represent a significant leap forward in pharmaceutical technology. This review highlights the importance of polymers in modern medicine, their potential to revolutionize drug delivery, and the ongoing efforts to optimize their use in clinical applications.

Smart Polymer Solution and Thermal Conductivity: How Important Is an Exact Polymer Conformation?

Smart Polymer Solution and Thermal Conductivity: How Important Is an Exact Polymer Conformation?

Hazardous Materials from Threats to Safety: Molecularly Imprinted Polymers as Versatile Safeguarding Platforms.

Hazards associated with highly dangerous pollutants/contaminants in water, air, and land resources, as well as food, are serious threats to public health and the environment. Thus, it is imperative to detect or decontaminate, as risk-control strategies, the possible harmful substances sensitively and efficiently. In this context, due to their capacity to be specifically designed for various types of hazardous compounds, the synthesis and use of molecularly imprinted polymers (MIPs) have become widespread. By molecular imprinting, affinity sites with complementary shape, size, and functionality can be created for any template molecule. MIPs' unique functions in response to external factors have attracted researchers to develop a broad range of MIP-based sensors with increased sensitivity, specificity, and selectivity of the recognition element toward target hazardous compounds. Therefore, this paper comprehensively reviews the very recent progress of MIPs and smart polymer applications for sensing or decontamination of hazardous compounds (e.g., drugs, explosives, and biological or chemical agents) in various fields from 2020 to 2024, providing researchers with a rapid tool for investigating the latest research status.

Sulfur-Dot-Mediated Synthesis of Smart Polymers for Heavy Metal Removal

Sulfur-Dot-Mediated Synthesis of Smart Polymers for Heavy Metal Removal

Photo-induced time-dependent controllable wettability of dual-responsive multi-functional electrospun MXene/polymer fibers

Switchable wettability potential in smart fibers is of paramount importance in various applications. Light-induced controllable changes in surface wettability have a significant role in this area. Herein, smart waterborne homopolymer, functional copolymer with different polarity and flexibility, and multi-functional terpolymer particles containing a time-dependent dual-responsive acrylated spiropyran, as a polymerizable monomer, were successfully synthesized through eco-friendly single-step emulsifier-free emulsion polymerization. Presence of 10 wt% of butyl acrylate and dimethylaminoethyl methacrylate relative to methylmethacrylate as functional comonomers decreased the Tg of the samples almost 20 ℃ and increased their polarity. The optical properties of the particles were investigated, and the UV–vis and fluorescence spectroscopy results showed that not only polarity and flexibility of the polymer chains may have a positive effect on improving the optical properties, but also the simultaneous presence of functional groups has a synergistic effect. The smart polymer particles with flexibility and polarity features exhibited higher absorption and emission compared to other samples. Inspired by these findings, multi-functional smart polymer fibers were prepared using the electrospinning method. The smart multi-functional electrospun fibers containing few-layer Ti3C2 MXenes were synthesized to improve the fibers’ properties and change the surface wettability due to the hydrophilic functional groups of MXene. Field-emission scanning electron microscopy images displayed the successful preparation of few-layer MXenes. Smooth and bead-free fibers with bright red fluorescence emission under UV irradiation were shown using fluorescence microscopy. The study on the surface wettability of fibers revealed that UV and visible light irradiation induced reversible time-dependent changes in the wettability of the smart multi-functional MXene/polymer electrospun fibers from hydrophobic to hydrophilic, reaching a water contact angle of 10° from an initial water contact angle of 100° under UV light and also changing to superhydrophilic state with passing time. Upon visible light exposure, the fibers returned to their original state. Furthermore, the fibers demonstrated a high stability over five alternating cycles of UV and visible light irradiation. This study shows that the fabrication of time-dependent smart fibers, utilizing the flexibility and polarity in the presence of MXenes, significantly improves and controls surface wettability changes. The outstanding dynamically photo-switchable wettability of these fibers may offer exciting opportunities in various applications, especially in the separation of oil from water contaminants.

Advancements in Castor Oil‐Derived Smart Materials: A Comprehensive Mini‐Review

AbstractSmart materials encompass a class of materials capable of reorienting themselves in response to external stimuli (heat, light, and chemical), and generate smart properties such as self‐healing (SH) and shape‐memory (SM), etc. Recently, castor oil has emerged as a bio‐renewable feedstock facilitating the synthesis of smart polymers such as polyurethanes and epoxidized castor oil (CO)‐based polymers. Furthermore, fillers and nanomaterials have been added to prepare responsive materials (SH and SM) and drug delivery systems. This review delves into the recent developments in CO‐based smart materials since 2015 under thermal, photo, and chemical stimuli and their applications in coating, adhesive, soft robotics, and drug delivery. Additionally, the challenges and future scopes for the development of castor oil‐based advanced smart materials have been discussed.

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.

A survey of conventional and smart polymers, with an emphasis on their novel uses in the textile industry

A survey of conventional and smart polymers, with an emphasis on their novel uses in the textile industry

Heterocyclic Hemipiperazines: Multistimuli-Responsive Switches and Sensors for Zinc or Cadmium Ions.

Advance in the design of molecular photoswitches - adapters that convert light into changes at molecular level - opens up exciting possibilities in preparing smart polymers, drugs photoactivated inside humans, or light-fueled nanomachines that might in the future operate in our bloodstream. Hemipiperazines are recently reported biocompatible molecular photoswitches based on cyclic dipeptides. Here we report a multistimuli-responsive hemipiperazine-based switch that reacts on light, solvents, acidity, or metal ions. Its photoequilibration is controlled by the intramolecular hydrogen bonding pattern. The compound can be used as a mid-nanomolar photoswitchable fluorescent sensor for zinc and cadmium ions, applicable to monitor environmental pollution in real time.

Enhanced Anti‐Cancer Efficacy of Hesperidin through Smart Polymeric Nanoparticles Targeting Prostate Cancer

AbstractThe rapid progress of various nanotechnology tools is currently being utilized in the management of several fatal illnesses, including cancer. Nanopolymers that encapsulate anti‐cancer medication present a highly encouraging substitute to traditional therapies, primarily because of their specific targeting and accurate functionality, making them suitable for a variety of uses. Poly(2‐hydroxyethyl methacrylate) (pHEMA) is a non‐toxic polymer derived from the monomer HEMA, which is known for its toxicity. It can be combined with various other polymers and is associated with minimal immune response. The objective of the current investigation is to produce smart polymeric nanoparticles that are responsive to changes in pH and temperature, and capable of encapsulating hesperidin. These hesperidin‐loaded poly(2‐Hydroxyethyl methacrylate‐N‐isopropylacrylamide‐Vinyl imidazole) nanoparticles, referred to as HesSNPs, aim to enhance the bioavailability of hesperidin and augment its therapeutic effectiveness in combating prostate cancer. N‐isopropylacrylamide and Vinyl imidazole were employed as monomers sensitive to temperature and pH, respectively. Nanopolymers that were synthesized underwent characterization through dynamic light scattering (DLS) analyses, scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) to analyze particle size and charge, surface morphology, and functional group determinations, respectively. HesSNPs decreased cell viability of DU‐145 cells. Flow cytometry analysis revealed that apoptosis is the main mechanism underlying cell death after HesSNPs treatment.

A Comprehensive Review of Stimuli-Responsive Smart Polymer Materials-Recent Advances and Future Perspectives.

Today, smart materials are commonly used in various fields of science and technology, such as medicine, electronics, soft robotics, the chemical industry, the automotive field, and many others. Smart polymeric materials hold good promise for the future due to their endless possibilities. This group of advanced materials can be sensitive to changes or the presence of various chemical, physical, and biological stimuli, e.g., light, temperature, pH, magnetic/electric field, pressure, microorganisms, bacteria, viruses, toxic substances, and many others. This review concerns the newest achievements in the area of smart polymeric materials. The recent advances in the designing of stimuli-responsive polymers are described in this paper.

Adhesion Evolution: Designing Smart Polymeric Adhesive Systems with On-Demand Reversible Switchability.

Smart polymeric switchable adhesives represent a rapidly emerging class of advanced materials, exhibiting the ability to undergo on-demand transitioning between "On" and "Off" adhesion states. By selectively tuning external stimuli triggers (including temperature, light, electricity, magnetism, and chemical agents), we can engineer these materials to undergo reversible changes in their bonding capabilities. The strategic design selection of stimuli is a pivotal factor in the design of switchable adhesive systems. This review outlines recent advancements in the field of smart switchable polymeric adhesives over the past decade with a focus on the selection of stimulus triggers. These systems are further categorized into one of four adhesion switching mechanisms upon initiation by a specific stimuli-trigger: (i) interfacial adhesion, (ii) stiffness, (iii) contact area, or (iv) suction-based switching. Evaluation of adhesion switching performance across systems is primarily made based on three key metrics: (i) maximum adhesion strength, (ii) switch ratio, and (iii) switch time. Different stimuli and mechanisms offer distinct advantages and limitations, influencing the performance characteristics and applicability of these materials across domains such as detachable biomedical devices, robotic grippers, and climbing robots. This review thus offers a perspective on the present advancements and challenges in this emerging field, along with insights into future directions.