Good Photothermal Properties Research Articles

Acrylate-functionalized porphyrin-covalent organic framework for bacterial-targeted and reaction-enhanced synergistic phototherapy/chemotherapy toward sterilization and wound healing.

Porphyrinic covalent organic frameworks (COFs) have emerged as prospective materials in photodynamic and photothermal sterilization. However, it is still a great challenge to construct an efficient COF-based sterilizing agent with good photothermal and photodynamic properties and bacterial targeting ability. Herein, we report a multifunctional porphyrin-COF for bacterial-targeted and reaction-enhanced synergistic phototherapy/chemotherapy for sterilization and wound healing. The ordered crystal structure of the porphyrin-COF not only effectively avoids the self-aggregation-induced quenching of the porphyrin monomer, but also facilitates the storage and transport of singlet oxygen. The acrylate substituent in the other monomer serves as a bacterial targeting moiety and the in situ reaction site with the sulfhydryl group of the bacterial surface protein via a Michael addition reaction, thus fixing the bacteria on the surface of COF and making them lose the colonization ability. Furthermore, the bonding of COF and bacteria further amplifies the therapeutic efficiency of phototherapy. Therefore, the developed multifunctional sterilization platform not only provides a new strategy for the design of novel bactericidal materials but also broadens the biological applications of COF-based materials.

Application of nanotechnology in bladder cancer diagnosis and therapeutic drug delivery.

Bladder cancer (BC) is one of the most common malignant tumors in the urinary system, and its high recurrence rate is a great economic burden to patients. Traditional diagnosis and treatment methods have the disadvantages of insufficient targeting, obvious side effects and low sensitivity, which seriously limit the accurate diagnosis and efficient treatment of BC. Due to their small size, easy surface modification, optical properties such as plasmon resonance, and surface enhanced Raman scattering, good electrical conductivity and photothermal conversion properties, nanomaterials have great potential application value in the realization of specific diagnosis and targeted therapy of BC. At present, the application of nanomaterials in the diagnosis and treatment of BC is attracting great attention and achieving rich research results. Therefore, this paper summarizes the recent research on nanomaterials in the diagnosis and treatment of BC, clarifies the existing advantages and disadvantages, and provides theoretical guidance for promoting the accurate diagnosis and efficient treatment of BC.

The multifunctional Prussian blue/graphitic carbon nitride nanocomposites for fluorescence imaging-guided photothermal and photodynamic combination therapy.

Cancer has been regarded as one of the most intractable diseases worldwide and threatens human health and life. Photothermal/Photodynamic therapy (PTT and PDT) have emerged as reliable and effective strategies in cancer treatment with the superiorities of non-invasiveness, slight side effects, and high treatment efficiency. Herein, a nanocomposite (PBCN) was fabricated via electrostatic interaction between Prussian blue nanoparticles (PBNPs) and graphitic carbon nitride (g-C3N4), and the resulting PBCN possessed good photothermal properties and excellent photodynamic effects with 808 nm irradiation. Furthermore, it exhibits excellent fluorescence imaging ability in cells, highlighting its potential as a powerful imaging agent in the biomedical field. Combination with a photothermal material, photosensitizer, and fluorescence imaging agent would thus allow PBCN to realize fluorescence imaging-guided PTT/PDT, showing an outstanding theranostic effect on cancer cells.

A biocompatible NIR-II light-responsive nanoknife for permanent male sterilization.

Nanomaterial-mediated photothermal therapy (PTT) is a promising strategy for permanent male sterilization owing to its easy operation, rapid heating, minimal invasiveness, and high spatiotemporal controllability. However, the currently available PTT for male sterilization utilizes irradiation sources in the first near-infrared window (NIR-I), which may suffer from incomplete sterilization due to the insufficient penetration depth of NIR-I light. Herein, we developed a facile one-pot hydrothermal synthetic method of cysteine-coated copper sulfide (Cys-CuS) nanosheets for the second NIR window (NIR-II) PTT-mediated permanent male sterilization. In this method, Cys acted not only as a template but also as a sulfur resource in the formation of Cys-CuS nanosheets. The obtained Cys-CuS nanosheets possessed good photothermal properties and satisfied deep-tissue light response capacity under 1064 nm laser exposure. Given this, the permanent male sterilization in vivo was readily achieved by Cys-CuS nanosheets in a rapid manner (only 40 s). To the best of our knowledge, it is the first time that nanomaterial-mediated NIR-II PTT is applied for permanent male sterilization. We believe that the facilely prepared biocompatible Cys-CuS nanosheets can serve as a promising NIR-II light-responsive nanoknife to control the overpopulation of domestic pets and stray animals.

The graphene-polyurethane foam-coated fabric with excellent photo-thermal property

Graphene-polyurethane (GR-PU) foam-coated fabric with good photo-thermal and heat insulation property were prepared using the simple and safe method of mechanical foaming with graphene, polyurethane, and cotton fabrics. The result showed that the temperature rise of the foam-coated fabric was 67 °C under simulated sunlight when the foaming ratio was 200 % and the graphene concentration was 1 wt% comparing to the original fabric with 37 °C. In addition, the heat insulation ability was also improved. The cross-plane thermal conductivity was 0.264 W·m−1·K−1 comparing to the original fabric with 0.361 W·m−1·K−1. At this point, the foam had a uniform size with a distribution density of 78 per 7.84 mm2 and contained a large amount of air contributing to the improvement of the photo-thermal and heat insulation property. The foam-coated fabric could be applied in the field of heat preservation and temperature regulation.

Cuprous oxide nanoparticles-based photothermal and chemodynamic synergistic therapy inhibits proliferation and migration of gastric cancer cells in vitro

To investigate the physicochemical characterization of cuprous oxide (Cu2O) nanoparticles and assess its antitumor effect against gastric cancer cells in vitro. The morphology, particle size and Fenton-like properties of Cu2O nanoparticles were analyzed using transmission electron microscopy (TEM), dynamic light scattering (DLS), zeta potential analysis and ultraviolet absorption spectroscopy. CCK-8 assay and Transwell experiments were used for evaluating the in vitro anti-tumor effect of the nanometers in gastric cancer cells. The prepared Cu2O nanoparticles had a quasi-circular structure with a diameter of about 100 nm. The temperature of the nanoparticles increased from 25 to 50 ℃ after irradiation with near-infrared light (NIR, 0.5W/cm2) for 5 min. At a nearly neutral pH (pH=6.5), the nanoparticles catalyzed the generation of a large amount of reactive oxygen species (ROS). CCK-8 assay and Transwell experiment showed that Cu2O nanoparticles concentration-dependently inhibited the proliferation, invasion and migration of gastric cancer cells. Cu2O nanoparticles have good photothermal and chemokinetic properties with a strong anti-tumor effect, and can potentially serve as a new therapeutic agent for gastric cancer treatment.

ICG-Dimeric Her2-Specific Affibody Conjugates for Tumor Imaging and Photothermal Therapy for Her2-Positive Tumors.

Human epidermal growth factor receptor 2 (Her2) is abundantly expressed in various solid tumors. The Her2-specific Affibody (ZHer2:2891) has been clinically tested in patients with Her2-positive breast cancer and is regarded as an ideal drug carrier for tumor diagnosis and targeted treatment. Indocyanine green (ICG) can be used as a photosensitizer for photothermal therapy (PTT), in addition to fluorescent dyes for tumor imaging. In this study, a dimeric Her2-specific Affibody (ZHer2) based on ZHer2:2891 was prepared using the E. coli expression system and then coupled to ICG through an N-hydroxysuccinimide (NHS) ester reactive group to construct a novel bifunctional protein drug (named ICG-ZHer2) for tumor diagnosis and PTT. In vitro, ICG-ZHer2-mediated PTT selectively and efficiently killed Her2-positive BT-474 and SKOV-3 tumor cells rather than Her2-negative HeLa tumor cells. In vivo, ICG-ZHer2 specifically accumulated in Her2-positive SKOV-3 tumor grafts rather than Her2-negative HeLa tumor grafts; high-contrast tumor optical images were obtained. However, Her2-negative HeLa tumor grafts were not detected. More importantly, ICG-ZHer2-mediated PTT exhibited a significantly enhanced antitumor effect in mice bearing SKOV-3 tumor grafts owing to the good photothermal properties of ICG-ZHer2. Of note, ICG-ZHer2 did not exhibit acute toxicity in mice during short-term treatment. Overall, our findings indicate that ICG-ZHer2 is a promising bifunctional drug for Her2-positive tumor diagnosis and PTT.

Multi-functional Fe3O4@HMPDA@G5-Au core-releasable satellite nano drug carriers for multimodal treatment of tumor cells

Combination therapy has become an effective strategy for tumor treatment, but the preparation of drug nanocarriers with the high requirements still lacked exploration. In this paper, hollow shell-layer mesoporous polydopamine (HMPDA) was constructed on Fe3O4 nanoparticles (the magnetic core), and small-sized G5-Au nanoparticles (AuNPs) as the releasable satellite carriers for tumor deep treatment were modified on HMPDA surface, then the nucleus-satellite Fe3O4@HMPDA@G5-Au nano drug delivery carriers were obtained. The therapy drug could be loaded in the mesoporous structure of HMPDA and G5-Au nanoparticles, so the drug loading capacity was relatively large. The Fe3O4@HMPDA@G5-Au composite nano carriers also had good photothermal properties, because polydopamine (PDA) and AuNPs were both good photothermal agents. Combination of photothermal therapy (PTT) and drug therapy could significantly enhance the ablation of tumor cells with minor side effects. In addition, the decomposition of H2O2 in the tumor site catalyzed by the AuNPs could also produce oxygen to alleviate tumor hypoxia. In addition, because of the magnetic properties of Fe3O4 nanoparticles, the Fe3O4@HMPDA@G5-Au nano drug delivery carriers also had magnetic targeting performance and could reach the specified position under the guidance of external magnetic field. The results showed that the average DOX loaded amount of the prepared carriers was 473.83 mg/g, the drug release rate in 24 h could achieve 61.3 %. The cytotoxicity test showed that the drug loaded carriers had a significant inhibitory effect on HepG2 cells. The drug-loaded core-satellite nanocarriers could play a good synergistic treatment effect on cancer under the multi effect synergy of PPT, drug therapy, magnetic targeting and pH-responsive drug release.

Biocompatible Ferrofluid Robot With Photothermal Property for Targeted Tumor Therapy

Magnetic-controlled micro-robots have promising applications in disease therapy due to their high targetability and drug utilization. Due to their unique deformable and divisible properties, ferrofluid robots have gained much attention in microchemical reaction chips and micromanipulation. This letter proposes a biocompatible ferrofluid robot and validates its potential to achieve targeted drug delivery and tumor cell killing. This biocompatible ferrofluidic robot contains 10 nm oleic acid-coated ferric tetroxide particles and vegetable oil and has good magnetic responsiveness, deformability, and photothermal properties, and can move in liquid environments such as blood. It can achieve motion with an error of less than 0.4 mm under closed-loop control and obstacle overturning and passage through narrow channels less than twice its diameter. In addition, the biocompatible ferrofluid robot can kill tumor cells in the target area due to the photothermal properties of the magnetic particles, and experimental results show that the tumor cell death rate can reach 95%. These capabilities give the biocompatible ferrofluid robot a significant advantage in getting the target location for cancer treatment through the vascular environment.

Porous photothermal antibacterial antioxidant dual–crosslinked cryogel based on hyaluronic acid/ polydopamine for non-compressible hemostasis and infectious wound repair

• A series of antioxidant and photothermal antibacterial dual–crosslinked cryogels was designed. • The cryogels showed stable mechanical property and biocompatibility. • These cryogels rapidly stopped irregularly shaped and non-compressible bleeding. • The cryogels significantly improved the MRSA-infected full-thickness skin defect wound healing. Cryogel dressings with good absorption ability and photothermal antibacterial properties for preventing wound infections and treating infected wounds have attracted widespread attention. In this work, a series of cryogels with macroporous structure, antioxidant and photothermal properties were prepared based on adipic dihydrazide modified hyaluronic acid (HA-ADH), and dopamine (DA). The antioxidant properties, hemostatic properties, near infrared (NIR) assisted photothermal antibacterial ability provided by polydopamine, recyclable compression mechanical properties, and cytocompatibility were tested. The results demonstrated that the HA-ADH/DA cryogels have stable mechanical properties, great antibacterial properties against E. coli (EC) and methicillin-resistant S. aureus (MRSA). The high swelling ratio due to the high water retention of HA equipped the cryogels with the capability of absorbing exuded blood and excessive tissue fluid in the infected full-thickness skin defect model of mouse. The cryogels demonstrated good cytocompatibility and antioxidant performance through cell tests and 1, 1-diphenyl-2-methylbenzohydrazino (DPPH) scavenging efficiency test. The cryogels showed enhanced blood-clotting index (BCI) and better hemostatic ability in the mouse liver trauma model and the rat deep non-compressible liver defect model compared with gauze and gelatin sponge. Furthermore, compared with commercial Tegaderm TM dressing in vivo , the HA-ADH/DA cryogels could greatly promote infected skin wound healing in a full-thickness infected skin defect wound model. In summary, the macroporous HA-ADH/DA cryogels with good antioxidant, high swelling ratio, photothermal antibacterial property, and biocompatibility are a promising hemostatic material and wound healing dressing.

Polydopamine-Based Nanoparticles for an Antibiofilm Platform: Influence of Size and Surface Charge on Their Penetration and Accumulation in S. aureus Biofilms.

Various functional polydopamine (PDA) nanoparticles have been developed to treat biofilms in recent years; however, in-depth knowledge of how the physicochemical properties of the nanoparticles impact their penetration and accumulation in biofilms is lacking. In this work, PDA nanoparticles of 15, 60, 90, and 200 nm sizes were synthesized and carboxyl, methoxy, and amine groups were introduced to the particle surface to control their surface charges, and then the penetration and accumulation of these PDA nanoparticles in S. aureus biofilms were investigated. The PDA nanoparticles of approximately 60 nm size (PDA60) showed higher penetration and accumulation abilities than nanoparticles of other sizes, and the positively charged amine groups introduced onto the surfaces of PDA60 nanoparticles were more effective than carboxyl or methoxy groups in promoting the interactions of the nanoparticles with the biofilm. The PDA60 nanoparticles with amine surface groups exhibited good photothermal properties, and confocal laser scanning microscopy revealed that they were able to accumulate in the biofilm in significant amounts, which upon irradiation with a laser of 808 nm wavelength showed a high bactericidal rate (97.1%) against the biofilm. The findings of this work provide guidance for the design and development of nanoparticles for antibiofilm application.

NIR-Ⅱ window Triple-mode antibacterial Nanoplatform: Cationic Copper sulfide nanoparticles combined vancomycin for synergistic bacteria eradication

The widespread use of antibiotics leads to the increasing drug resistance of bacteria and poses a threat to human health. Therefore, there is an urgent need to develop new antibacterial strategies. Herein, based on the good photothermal properties of Copper sulfide (CuS) nanoparticles under near infrared (NIR) laser, we developed a NIR-Ⅱ window triple-mode synergetic antibacterial cCuS (cationic CuS) @Vancomycin (Van) nanoplatform. In the proposed nanoplatform, the positive charge on the surface makes cCuS@Van nanoplatform show better bacterial uptake and membrane damage; vancomycin induces chemical sterilization and provides a targeting effect to the nanoplatform; combined with the strong photothermal effect and deep tissue penetration at the excitation of 1064 nm laser, cCuS@Van nanoplatform can effectively kill bacterial. The photothermal conversion efficiency of the nanoplatform can reach 49.12 % and in vitro experiments show a sterilizing rate of more than 99.5 % to staphylococcus aureus (S. aureus) at the concentration of 3.0 μM, which also demonstrated the synergistic effect of cCuS@Van nanoplatform. In addition, low cytotoxicity to human cells conforms the good biocompatibility of the as-prepared cCuS@Van nanoplatform, which endows it a good application prospect in the field of antibacterial, such as wound healing and implant sterilization.

Janus Biopolymer Sponge with Porous Structure Based on Water Hyacinth Petiole for Efficient Solar Steam Generation.

Solar-driven steam generation for desalination is a facile, sustainable, and energy-saving approach to produce clean freshwater. However, the complicated fabrication process, high cost, potential environmental impact, and salt crystallization of conventional evaporators limit their large-scale application. Herein, we present a sustainable Janus evaporator based on a biopolymer sponge from the water hyacinth petiole (WHP) for high-performance solar steam generation. The freeze-dried WHP maintained its original porous structure and aligned channels well, and therefore holds the capability for rapid water transport due to strong capillary action. The WHP coated with carbon nanotubes/ethyl cellulose paste on its surface (WHP-C) gains a good photothermal property, thus achieving an efficient solar steam generation with a rate of 1.50 kg m−2 h−1 under 1 sun irradiation. Moreover, the WHP-C after hydrophobic modification by fluorocarbon (WHP-CH) is endowed with high water repellency and exhibits good salt resistance during long-term solar desalination. Additionally, we demonstrate that a stable wet surface that enables efficient water supply and vapor escape is also significant to the successive desalination of a solar evaporator. Our work provides new insights into the high-value utilization of biomass waste, i.e., water hyacinth, and the development of sustainable interfacial solar evaporators for the environmentally friendly production of freshwater.

Fabrication of multi-functional bio-based vitrimer and conductive composites via ugi four-component polymerization

To alleviate the pressure of fossil fuels on the environment, a green and efficient idea is proposed to prepare a new class of bio-based vitrimers by introducing dynamic disulfide bonds into the cross-linked network with bio-based raw materials 1,8-methane diamine and 10-undecenal through Ugi four-component reaction and highly efficient UV curing method. Among these bio-based vitrimers, B-MDU16 displays excellent self-healing ability, reprocessability and shape memory ability. Furthermore, conductive vitrimer composites based on bio-based vitrimers were fabricated by doping 5 wt% of MWCNTs, which also exhibited good electrical conductivity, photo-thermal properties, reprocessability and degradability as well as promising applications in the field of skin sensing. This study proposes to use Ugi-4CR to prepare bio-based vitrimer and composites, revitalizing this “ancient” organic reaction in the smart composites field and sustainable development strategy.

Design of Biocompatible Chitosan/Polyaniline/Laponite Hydrogel with Photothermal Conversion Capability.

In recent years, multifunctional hydrogels have received a great deal of attention because they are biocompatible and can mimic the extracellular matrix. Herein, we prepared hydrogels of biocompatible cross-linked networks with photothermal properties. In this study, a chitosan/polyaniline/laponite (COL) hydrogel with photothermal conversion capability was designed. Polyaniline was firstly grafted onto chitosan and its solution was mixed with oxidized dextran, which was then cross-linked into a hydrogel via a Schiff base reaction. Furthermore, an aluminosilicate clay material, laponite (LAP), was incorporated into the hydrogel. The swelling ratio of the COL hydrogel in various solutions was greater than 580%, and it showed good degradation ability (the mass–loss ratio was over 45% after 28 days). This composite hydrogel was demonstrated to have good photothermal conversion properties and biocompatibility at both the cell (cell viability was over 97%) and animal levels. The COL hydrogel showed a photothermal conversion efficiency of 23.7% under the irradiation of a near-infrared laser. Coupled with the osteogenic differentiation-inducing potential of LAP, the COL hydrogel has the potential to kill tumors via hyperthermia or serve as scaffolds for bone tissue regeneration.

Multifunctional MXene/CNT-based layered film for icing detection, anti-icing, and deicing application

Icing phenomenon usually happens in our daily life, especially in the cold winter or in high altitude areas, which makes us feel inconvenient and greatly threats some fields such as civil aviation or the manufacturing industry. In this study, a multifunctional film with properties of icing detection, anti-icing and deicing was fabricated. One-dimensional material carbon nanotube (CNT) and two-dimensional material Ti3C2Tx MXene were combined by two-step vacuum filtration. Polydimethylsiloxane (PDMS) as the flexible hydrophobic materials was then used to encapsulate layered film. Additionally, PDMS curing process on the sandpaper could make the surface of MXene/CNT layered film possess micro-structures. The low surface energy material PDMS and rough surface structures endow MXene/CNT layered film with good water-repellency. Compared with pure PDMS film (103°), the contact angle of MXene/CNT layered film surface reaches 128°. The result exhibits that a waterdrop(100uL) on the layered film surface takes 1425s to be frozen, which takes longer time than glass and pure PDMS. Additionally, excellent sensibility of the layered film could be used to detect icing phenomenon. The result manifests that gauge factor (GF) of MXene/CNT film reaches 15051 so that different icing stages could be identified by layered film clearly. MXene/CNT layered film possesses good electric heating and photo-thermal properties. The result shows that surface temperature can reach 89 °C with the 2.5 V voltage supply, and temperature reaches 95 °C through the radiation of near-infrared lamp as well. The dual-driven heating of MXene/CNT layered film shows the ability of deicing. 1000 mg ice just takes 223s to be melted entirely by 2.5 V input voltage, and 269s by radiation of 200 mW/cm2, respectively. The multifunctional MXene/CNT based layered film prepared by a simple fabrication method that integrates hydrophobicity, dual-driven heating, and sensibility together, which shows potential application in icing detection, anti-icing, and deicing.

Nitrogen-doped carbon dots/curcumin nanocomposite for combined Photodynamic/photothermal dual-mode antibacterial therapy

Due to their excellent photophysical properties, carbon quantum dots have great potential in biomedical and drug delivery fields. In this study, nitrogen-doped carbon quantum dots with good water solubility were prepared using citric acid and ethylenediamine as precursors, and compounded with curcumin, a photosensitive component, to produce composite nanomaterials with photodynamic therapy and synergistic photothermal therapy. The formation of nitrogen-doped carbon quantum dots and composite nanomaterials was verified using physical and optical means. In addition, the composite nanomaterials produced single-linear oxygen and exacerbated the increase of solution temperature under blue (405 nm) and near-infrared (808 nm) light irradiation, respectively. The plate counting method showed that the composite nanomaterials exhibited good photodynamic synergistic photothermal antibacterial properties against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus under dual light source (405+808 nm) irradiation, which improved the photoinactivation of curcumin against bacteria. In addition, the composite nanomaterials exhibited low toxicity and good hemocompatibility. These experimental results suggested that the composite nanomaterials showed great potential in a multimodal photodynamic therapy synergistic photothermal treatment platform.

Confined Construction of Ultrasmall Molybdenum Disulfide-Loaded Porous Silica Particles for Efficient Tumor Therapy.

Recently, molybdenum sulfide (MoS2) has shown great application potential in tumor treatment because of its good photothermal properties. Unfortunately, most of the current molybdenum disulfide-based nanotherapeutic agents suffer from complex preparation processes, low photothermal conversion efficiencies, and poor structural/compositional regulation. To address these issues, in this paper, a facile "confined solvothermal" method is proposed to construct an MoS2-loaded porous silica nanosystem (designated as MoS2@P-hSiO2). The maximum photothermal efficiency of 79.5% of molybdenum-based materials reported in the literature at present was obtained due to the ultrasmall MoS2 nanoclusters and the rich porous channels. Furthermore, both in vitro and in vivo experiments showed that the cascade hybrid system (MoS2/GOD@P-hSiO2) after efficient loading of glucose oxidase (GOD) displayed a significant tumor-suppressive effect and good biosafety through the combined effects of photothermal and enzyme-mediated cascade catalytic therapy. Consequently, this hybrid porous network system combining the in situ solvothermal strategy of inorganic functional components and the efficient encapsulation of organic enzyme macromolecules can provide a new pathway to construct synergistic agents for the efficient and safe treatment of tumors.

Ferrocene-based multifunctional nanoparticles for combined chemo/chemodynamic/photothermal therapy

Ferrocene and its derivatives have great potential for biomedical applications, but few related studies have been reported. In this study, copper ions and ferrocene derivatives were used for the first time to construct the ferrocene-based nanoparticles (Cu-Fc) with a hydrated particle size of approximately 220 nm. Their good photothermal conversion properties were verified in vitro and in vivo for the first time, indicating that they could be used as a novel photothermal agent for tumor treatment. In addition, the nanoparticles exhibited efficient Fenton effect under weakly acidic conditions, indicating that they can generate hydroxyl radicals (OH) to kill tumors in the weakly acidic environment of the tumor-specific microenvironment. More importantly, the nanoparticles can deplete glutathione (GSH), thus further enhancing Fenton effect-mediated chemodynamic therapy (CDT). Multifunctional ferrocene-based nanoparticles (DOX@Cu-Fc) were obtained after loading the chemotherapeutic drug doxorubicin hydrochloride (DOX). The results of in vitro and in vivo experiments showed that DOX@Cu-Fc could enhance tumor treatment by the combination of chemo/CDT/photothermal therapy (PTT).

In-situ deposition preparation of n-octadecane@Silica@Polydopamine-doped polypyrrole microcapsules for photothermal conversion and thermal energy storage of full-spectrum solar radiation

Phase change materials （PCMs） play an essential role in utilizing solar energy. However, there exist inherent defects of pure PCMs, such as low solar energy utilization efficiency and easy leakage. In this work, we successfully prepared a novel type of n-octadecane@Silica@Polydopamine-doped polypyrrole photothermal phase change microcapsules (SCN@PAP micro-PCMs), contained n-octadecane (n-OD) as the core material, silica as the intermediate layer, and polydopamine and polypyrrole composite (PDA-PPY) as the wall material. The microcapsules' morphology, chemical structure, photothermal and thermal storage properties, and thermal stability were investigated. This study confirmed that polydopamine (PDA) doping positively regulates the optical properties of polypyrrole (PPY). The PDA-PPY(PAP) was uniformly deposited on the surface of n-OD@SiO2 phase change microcapsules (SCN micro-PCMs) in granular form with the appropriate doping ratio. Further, tuning the ratio of SCN micro-PCMs to PAP and pyrrole (PY) to dopamine (DA) could endow SCN micro-PCMs with good photothermal properties and retain high thermal storage properties. When the mass ratio of PY: DA = 1:0.032 and SCN: PAP = 6:1, the prepared SCN@PAP micro-PCMs exhibited high photothermal conversion efficiency up to 97.31%, with a melting enthalpy of 145.3 J/g. The enthalpy value decreased by less than 1 J/g after 100 heating and cooling cycles demonstrating excellent thermal energy storage cycling stability. The SCN@PAP micro-PCMs are expected to be promising in promoting the efficient utilization of solar radiation.