Trimethylene Carbonate Research Articles

Reinvestigation of the ring-opening polymerization of ε-caprolactone with 1,8-diazacyclo[5.4.0]undec-7-ene organocatalyst in bulk

1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU) was used as organocatalyst to reinvestigate the ring-opening polymerization (ROP) of ε-caprolactone (CL) with benzyl alcohol (BnOH) initiator in bulk at 90 °C considering the unsuccessful ROP of CL at RT in previously reported publications. Kinetic study indicates that the PCLs could be well-designed with a controlled/living character of polymerization. The use of functional initiators, such as 2-hydroxyethyl methacrylate (HEMA), propargyl alcohol (PGA), 6-azido-1-hexanol (AHA) and methoxy poly(ethylene glycol) (mPEG) leads to end-functionalized PCLs. Accordingly, the block copolymerization of CL with δ-valerolactone (VL), trimethylene carbonate (TMC) and lactide (LA) successfully proceeded to give PCL-b-PVL, PCL-b-PTMC and PCL-b-PLA copolymers. Finally, the reaction mechanism was studied with DFT calculations and NMR measurements.

Therapeutic Stomatocytes with Aggregation Induced Emission for Intracellular Delivery.

Bowl-shaped biodegradable polymersomes, or stomatocytes, have much potential as drug delivery systems, due to their intriguing properties, such as controllable size, programmable morphology, and versatile cargo encapsulation capability. In this contribution, we developed well-defined therapeutically active stomatocytes with aggregation-induced emission (AIE) features by self-assembly of biodegradable amphiphilic block copolymers, comprising poly(ethylene glycol) (PEG) and AIEgenic poly(trimethylene carbonate) (PTMC) moieties. The presence of the AIEgens endowed the as-prepared stomatocytes with intrinsic fluorescence, which was employed for imaging of cellular uptake of the particles. It simultaneously enabled the photo-mediated generation of reactive oxygen species (ROS) for photodynamic therapy. The potential of the therapeutic stomatocytes as cargo carriers was demonstrated by loading enzymes (catalase and glucose oxidase) in the nanocavity, followed by a cross-linking reaction to achieve stable encapsulation. This provided the particles with a robust motile function, which further strengthened their therapeutic effect. With these unique features, enzyme-loaded AIEgenic stomatocytes are an attractive platform to be exploited in the field of nanomedicine.

Synthesis of ester-free type poly(trimethylene carbonate) derivatives bearing cycloalkyl side groups

Our ultimate goal is to create a library of ester-free type trimetylene carbonate derivatives, so that we can design and produce poly(trimethylene carbonate) (PTMC) derivatives that meet application needs. Herein we introduced cycloalkyl groups (cyclopentyl, cyclohexyl and cycloheptyl groups) into the side chain of an ester-free type PTMC. Previously, ester-free type PTMC derivatives with aromatic rings in the side chain have been reported from our group, but there have been no reports of aliphatic cyclic compounds introduced with ether linkage into their side chains. This research makes possible the production of more versatile ester-free PTMC derivatives using cycloalkyl groups. The effect of ring size was also investigated. All of the monomers gave homopolymers with Mn of a few thousands, improving the thermal degradation temperatures, compared to unmodified PTMC. We found a tendency towards increasing glass transition temperature with larger ring size.

One-Shot synthesis of heterografted brush copolymers through orthogonal Ring-Opening polymerization and atom transfer radical polymerization

• One-shot heterografted brush copolymers synthesis based on simultaneously orthogonal ring-opeing polymerization (ROP) and atom transfer radical polymerization (ATRP). • The dule role of DBU as the catalyst of ROP and the ligand of ATRP. • Brush copolymers with biodegradable polycarbonates or polyesters and poly(meth)acrylates or polystyrenes heterografts. • The self-assemble of the amphiphilic brush copolymer prepared with the one-shot method. The characteristics of brush copolymers enable them applicable materials in catalysis, pharmaceutical and compatibilizer, and the scope of the application could be greatly expanded through the regulating of grafted branches. In this manuscript, the one-shot orthogonal preparation of heterografted brush copolymers has been achieved successfully with 1,8-diazabicyclo [5.4.0] undec-7-ene (DBU) as the catalyst of ring-opening polymerization (ROP) and ligand of atom transfer radical polymerization (ATRP), avoiding the tedious purification processes in the two-step procedure for the synthesis of heterografted brush copolymers. Well-defined brush copolymers with various contents of poly(trimethylene carbonate) (PTMC) and poly( tert -butyl methacrylate) (P t BMA) graftings have been successfully prepared and the range of this method was further evaluated with a variety of cyclic and vinyl monomers in one-shot. Amphiphilic brush copolymer has also been successfully prepared allowing for the formation of micelles in water through self-assembling.

Amphiphilic chitosan-g-poly(trimethylene carbonate) – A new approach for biomaterials design

The paper presents the synthesis and characterization of poly(trimethylene carbonate) grafted chitosan as a new water soluble biopolymer suitable for in vivo applications. The synthesis was performed via ring-opening polymerization of 1,3-dioxan-2-one (trimethylene carbonate) (TMC) monomer, initiated by the functional groups of chitosan in the presence of toluene as solvent/swelling agent. By varying the molar ratio between the glucosamine units of chitosan and TMC, a series of chitosan derivatives with different content of poly(trimethylene carbonate) chains was synthetized. The structural characterization of the polymers was realized by FTIR and 1H NMR spectroscopy and their solubility was assessed in water and in organic solvents as well. The biocompatibility was investigated by MTS assay on Normal Human Dermal Fibroblasts, and the biodegradability was evaluated in lysozyme buffer solution. Further, the surface properties of the polymer films were analyzed by polarized optical microscopy, atomic force microscopy and water-to-air contact angle measurements. It was established that, by 5% substitution of chitosan with poly(trimethylene carbonate) chains having an average polymerization degree of 7, a water soluble polymer can be attained. Compared to the pristine chitosan, it has improved biocompatibility in solution and moderate wettability and higher biodegradability rate in solid state, pointing its suitability for in vivo applications.

Synthesis and characterization of poly(trimetylene carbonate-co-ε-caprolactone) prepared by ring-opening polymerization using samarium(III) acetate as initiator

Random copolymers of trimethylene carbonate and ε-caprolactone were synthesized by ring-opening polymerization varying the feed ratio. For this, samarium (III) acetate was used as an initiator at 110 °C for 24 h. The structure of copolymers was characterized by nuclear magnetic resonance spectroscopy and size exclusion chromatography, and differential scanning calorimetry was used to determine thermal properties. The effect of monomer feed composition on the copolymerization was analyzed, showing that the composition of the copolymers (F CL/F TMC), agreed with the feed dose. Conversion studies were made, and reactivity ratios of both monomers (rn ) were obtained, their values were r CL = 0.849 for caprolactone (CL) and r TMC = 1.261 for trimethylene carbonate (TMC), which indicated that TMC was more active than CL.

Small, Smart, and LDLR-Specific Micelles Augment Sorafenib Therapy of Glioblastoma.

Targeted molecular therapy, for example, with sorafenib (SF) is considered as a new and potent strategy for glioblastoma (GBM) that remains hard to treat today. Several clinical trials with SF, as monotherapy or combination therapy with current treatments, have not met the clinical endpoints, likely as a result of the blood-brain barrier (BBB) and inferior GBM delivery. Here, we designed and explored small, smart, and LDLR-specific micelles to load SF (LDLR-mSF) and to improve SF therapy of GBM by enhancing BBB penetration, GBM accumulation, and cell uptake. LDLR-mSF with 2.5% ApoE peptide functionality based on poly(ethylene glycol)-poly(ε-caprolactone-co-dithiolane trimethylene carbonate)-mefenamate exhibited nearly quantitative SF loading, small size (24 nm), high colloidal stability, and glutathione-activated SF release. The in vitro and in vivo studies certified that LDLR-mSF greatly enhanced BBB permeability and U-87 MG cell uptake and caused 10.6- and 12.9-fold stronger anti-GBM activity and 6.0- and 2.5-fold higher GBM accumulation compared with free SF and non-LDLR mSF controls, respectively. The treatment of an orthotopic human GBM tumor model revealed that LDLR-mSF at a safe dosage of 15 mg of SF/kg significantly retarded tumor progression and improved the survival rate by inducing tumor cell apoptosis and inhibiting tumor angiogenesis. These small, smart, and LDLR-specific micelles provide a potential solution to enhance targeted molecular therapy of GBM.

Copolymerization of carbon dioxide and oxetane catalyzed by aluminum porphyrin complex system

AbstractTetraphenylporphinatoaluminum chloride ([TPP]AlCl) catalyst and tetra‐n‐butylammonium bromide (TBAB) cocatalyst system is effective for the copolymerization of CO2 and oxetane even under low CO2 pressure (~2 MPa). In the presence of toluene as a solvent, poly(trimethylene carbonate) (PTMC) containing >99% of carbonate linkages with Mn = 8600 and Mw/Mn = 1.70 was synthesized. This is the first report of PTMC formation with excellent ratio of carbonate linkages from oxetane and CO2. According to the kinetic analysis, proton nuclear magnetic resonance (1H NMR) and matrix assisted laser desorption/ionization time‐of‐flight mass spectrometry (MALDI‐TOF/MS) measurements of the products, PTMC was mainly synthesized via (i) the trimethylene carbonate (TMC) formation from CO2 and oxetane and (ii) the successive ring‐opening polymerization of TMC.

The timing of laparoscopic cholecystectomy and nano-ligation clip for acute calculous cholecystitis under guidance of Tokyo guidelines 2018 (multi-center retrospective analysis)

Laparoscopic cholecystectomy (LC) has been recognized as the standard surgical method for cholecystectomy. A nano-absorbable ligation clip. The material used in the ligation clip is composed of basic materials (poly(p-dioxanone), poly trimethylene carbonate or polycaprolactone) and nano-short fibers (Polyglycolide acid or polylactide). The short nano-fibers maintain the crystalline form evenly dispersed in the base material. The diameter of short nano-fibers is 300–500 nm and the length is 20–50 µm. The nano-absorbable ligation clip has strong closing force and will not cause closure failure. However, there are still some controversies about the optimum time for LC treatment of acute calculous cholecystitis (ACC) patients, and the optimum time for performing LC based on evidence-based medicine has not been unanimously recognized. Here, we explore LC timing for ACC treatment under the guidance of the Tokyo Guidelines for Acute Cholecystitis 2018 (TG18). We retrospectively analyzed the data of 3,147 ACC cases undergoing LC in eight hospitals in China. According to the time from the onset of the patient’s symptoms to the operation, they were divided into the following three groups: Group A (onset to operation time of ≤3 days), Group B (onset to operation time of 4–7 days), and Group C (onset to operation time of >7 days). There was no obvious statistical difference in preoperative indicators, such as gender ratio, history of hypertension, diabetes, and abdominal operation; ASA Classification; and TG18 Classification between the three groups. Similarly, the results of preoperative laboratory indices (e.g., white blood cell, C-reactive protein, procalcitonin, platelet, serum creatinine, and international normalized ratio) showed no obvious statistical difference between the three groups. The comparison of gallbladder characteristics under B-ultrasound showed no significant statistical difference between the three groups. However, the conversion rate in Group C was significantly higher than that in Groups A and B, the incidence of complications (e.g., bile leakage, bile duct injury, and wound infection) was significantly higher in Group C than that in Groups A and B, and the postoperative hospital stay was significantly shorter in Group A than that in Groups B and C. A comprehensive analysis of patients’ medical records in multiple medical centers confirms that it is safe and feasible to perform early LC 7 days before the onset of ACC, which can significantly decrease postoperative complications and shorten the postoperative hospital stay for ACC patients. Performing early LC for ACC patients under the TG18 guidelines is safe and feasible. Additionally, since TG18 has obvious practicability and guidance for the clinical practice of hepatobiliary surgery, it is worthy of popularization and application in China.

Going Beyond Sweep Voltammetry: Alternative Approaches in Search of the Elusive Electrochemical Stability of Polymer Electrolytes

Solid polymer electrolytes (SPEs) are promising candidates for solid-state lithium-ion batteries. Potentially, they can be used with lithium metal anodes and high-voltage cathodes, provided that their electrochemical stability is sufficient. Thus far, the oxidative stability has largely been asserted based on results obtained with sweep voltammetry, which are often determined and reliant on arbitrary assessments that are highly dependent on the experimental conditions and do not take the interaction between the electrolyte and the electrode material into account. In this study, alternative techniques are introduced to address the pitfalls of sweep voltammetry for determining the oxidative stability of SPEs. Staircase voltammetry involves static conditions and eliminates the kinetic aspects of sweep voltammetry, and coupled with impedance spectroscopy provides information of changes in resistance and interphase layer formation. Synthetic charge–discharge profile voltammetry applies the real voltage profile of the active material of interest. The added effect of the electrode active material is investigated with a cut-off increase cell cycling method where the upper cut-off voltage during galvanostatic cycling is gradually increased. The feasibility of these techniques has been tested with both poly(ethylene oxide) and poly(trimethylene carbonate) combined with LiTFSI, thereby showing the applicability for several categories of SPEs.

Photo-Cross-Linked Poly(trimethylene carbonate)/Poly(ε-caprolactone) Triblock Copolymers with Controlled Architectures: From Phase-Separated Structures to Shape-Memory Materials

Photo-Cross-Linked Poly(trimethylene carbonate)/Poly(ε-caprolactone) Triblock Copolymers with Controlled Architectures: From Phase-Separated Structures to Shape-Memory Materials

More Precise Control of the In Vitro Enzymatic Degradation via Ternary Self-Blending of High/Medium/Low Molecular Weight Poly(trimethylene carbonate)

To more precisely control the degradation rate of poly(trimethylene carbonate) (PTMC), self-blending films were prepared via the ternary self-blending of pure PTMC with a molecular weight of 334, 152, and 57 kg/mol. The in vitro enzymolysis degradation of the ternary self-blending films was performed in lipase solutions. The results showed that ternary self-blending could control the degradation of PTMC by adjusting the mass ratio of high/medium/low molecular weight PTMC in the composition, and the PTMC334/PTMC152/PTMC57 films with a mass ratio of 1/4/16 showed mass loss of 85.96% after seven weeks of degradation, while that of PTMC334/PTMC152/PTMC57 films with a mass ratio of 1/1/1 was 96.39%. The former and latter’s degradation rate constant was 13.263 and 23.981%/w, respectively, and the former presented better morphology stability than the latter. The strategy of ternary self-blending could simultaneously bestow PTMC with a lower degradation rate and good morphology stability, indicating that ternary self-blending is an efficient way to control the degradation performance of PTMC more precisely.

Photoprintable Gelatin-graft-Poly(trimethylene carbonate) by Stereolithography for Tissue Engineering Applications.

The stereolithography process is a powerful additive manufacturing technology to fabricate scaffolds for regenerative medicine. Nevertheless, the quest for versatile inks allowing one to produce scaffolds with controlled properties is still unsatisfied. In this original article, we tackle this bottleneck by synthesizing a panel of photoprocessable hybrid copolymers composed of gelatin-graft-poly(trimethylene carbonate)s (Gel-g-PTMCn). We demonstrated that by changing the length of PTMC blocks grafted from gelatin, it is possible to tailor the final properties of the photofabricated objects. We reported here on the synthesis of Gel-g-PTMCn with various lengths of PTMC blocks grafted from gelatin using hydroxy and amino side groups of the constitutive amino acids. Then, the characterization of the resulting hybrid copolymers was fully investigated by quantitative NMR spectroscopy before rendering them photosensitive by methacrylation of the PTMC terminal groups. Homogeneous composition of the photocrosslinked hybrid polymers was demonstrated by EDX spectroscopy and electronic microscopy. To unravel the individual contribution of the PTMC moiety on the hybrid copolymer behavior, water absorption, contact angle measurements, and degradation studies were undertaken. Interestingly, the photocrosslinked materials immersed in water were examined using tensile experiments and displayed a large panel of behavior from hydrogel to elastomer-like depending on the PTMC/gel ratio. Moreover, the absence of cytotoxicity was conducted following the ISO 10993 assay. As a proof of concept, 3D porous objects were successfully fabricated using stereolithography. Those results validate the great potential of this panel of inks for tissue engineering and regenerative medicine.

Sulfur-substitution-enhanced crystallization and crystal structure of poly(trimethylene monothiocarbonate)

In this paper, the crystallization behavior of a novel poly(monothiocarbonate), poly(trimethylene monothiocarbonate) (PTMMTC), was investigated and compared with its polycarbonate analogue, poly(trimethylene carbonate) (PTMC). It is found that PTMMTC exhibits strong crystallizability, while unstretched PTMC is amorphous. DSC and DMA results reveal that PTMMTC possesses higher glass transition temperature (Tg) and β-transition temperature (Tβ) than PTMC. Simulation based on density functional theory (DFT) shows that, the bond angle of C-S-C is evidently smaller than that of C-O-C, and thus a larger dipole moment. This leads to the stronger intermolecular interaction and more rigid chain conformation in PTMMTC, which is the origin of sulfur-substitution enhanced crystallization. The crystal structure of PTMMTC was preliminarily determined for the first time. PTMMTC has an orthorhombic crystal structure with a planar zig-zag chain conformation. The parameters of unit cell are a = 10.74 Å, b = 4.79 Å, and c (fiber axis) = 7.74 Å.

Unique Carbonate-Based Single Ion Conducting Block Copolymers Enabling High-Voltage, All-Solid-State Lithium Metal Batteries.

Safety and high-voltage operation are key metrics for advanced, solid-state energy storage devices to power low- or zero-emission HEV or EV vehicles. In this study, we propose the modification of single-ion conducting polyelectrolytes by designing novel block copolymers, which combine one block responsible for high ionic conductivity and the second block for improved mechanical properties and outstanding electrochemical stability. To synthesize such block copolymers, the ring opening polymerization (ROP) of trimethylene carbonate (TMC) monomer by the RAFT-agent having a terminal hydroxyl group is used. It allows for the preparation of a poly(carbonate) macro-RAFT precursor that is subsequently applied in RAFT copolymerization of lithium 1-[3-(methacryloyloxy)propylsulfonyl]-1-(trifluoromethylsulfonyl)imide and poly(ethylene glycol) methyl ether methacrylate. The resulting single-ion conducting block copolymers show improved viscoelastic properties, good thermal stability (Tonset up to 155 °C), sufficient ionic conductivity (up to 3.7 × 10–6 S cm–1 at 70 °C), and high lithium-ion transference number (0.91) to enable high power. Excellent plating/stripping ability with resistance to dendrite growth and outstanding electrochemical stability window (exceeding 4.8 V vs Li+/Li at 70 °C) are also achieved, along with enhanced compatibility with composite cathodes, both LiNiMnCoO2 – NMC and LiFePO4 – LFP, as well as the lithium metal anode. Lab-scale truly solid-state Li/LFP and Li/NMC lithium-metal cells assembled with the single-ion copolymer electrolyte demonstrate reversible and very stable cycling at 70 °C delivering high specific capacity (up to 145 and 118 mAh g–1, respectively, at a C/20 rate) and proper operation even at a higher current regime. Remarkably, the addition of a little amount of propylene carbonate (∼8 wt %) allows for stable, highly reversible cycling at a higher C-rate. These results represent an excellent achievement for a truly single-ion conducting solid-state polymer electrolyte, placing the obtained ionic block copolymers on top of polyelectrolytes with highest electrochemical stability and potentially enabling safe, practical Li-metal cells operating at high-voltage.

Characteristics of Polycarbonate Soft Segment-Based Thermoplastic Polyurethane

The pre-experiment of the present study revealed that polyurethane (PU) synthesized using poly (hexamethylene carbonate) glycol (PHC) has high melt viscosity and is difficult to process. Therefore, poly (trimethylene carbonate) glycol (PTC) was employed to synthesize a PU product with low melt viscosity. First, four types of thermoplastic polyurethane (TPU) were formed through one-step solvent-free synthesis. TPU is presented in the format “TPU-X-Y,” with X representing the polyol (PTC or PHC, around 1000 molecular weight) and Y the chain extender (1,3-propane diol [PDO] or 1,4-butane diol [BDO]) used. The TPU was synthesized using a fixed molar ratio of (isocyanate):(polyol):(chain extender) = 2:1:1 and compared. The results indicated that chain entanglement often occurred among the long carbon chains of PHC. The synthesized TPU employed a property of PTC, namely converting polarity into reverse polarity in high temperatures, to resolve the high melt viscosity of TPU of the PHC series, which causes processing difficulties. The synthesized TPU-PTC-PDO exhibited favorable molecular arrangements. Given its polarity, TPU-PTC-PDO has outstanding tensile properties (strength at break: 41.10 ± 10.78 MPa; 100% modulus = 6.73 ± 0.12 MPa), making processing at lower temperatures (180 or 190 °C) feasible. With the inclusion of PTC, the synthesized polycarbonate TPU exhibits the advantages of polycarbonate and is suitable for a wide range of applications.

A surface-eroding poly(1,3-trimethylene carbonate) coating for magnesium based cardiovascular stents with stable drug release and improved corrosion resistance

Magnesium alloys with integration of degradability and good mechanical performance are desired for vascular stent application. Drug-eluting coatings may optimize the corrosion profiles of magnesium substrate and reduce the incidence of restenosis simultaneously. In this paper, poly (trimethylene carbonate) (PTMC) with different molecular weight (50,000 g/mol named as PTMC5 and 350,000 g/mol named as PTMC35) was applied as drug-eluting coatings on magnesium alloys. A conventional antiproliferative drug, paclitaxel (PTX), was incorporated in the PTMC coating. The adhesive strength, corrosion behavior, drug release and biocompatibility were investigated. Compared with the PLGA control group, PTMC coating was uniform and gradually degraded from surface to inside, which could provide long-term protection for the magnesium substrate. PTMC35 coated samples exhibited much slower corrosion rate 0.05 μA/cm2 in comparison with 0.11 μA/cm2 and 0.13 μA/cm2 for PLGA and PTMC5 coated counterparts. In addition, PTMC35 coating showed more stable and sustained drug release ability and effectively inhibited the proliferation of human umbilical vein vascular smooth muscle cells. Hemocompatibility test indicated that few platelets were adhered on PTMC5 and PTMC35 coatings. PTMC35 coating, exhibiting surface erosion behavior, stable drug release and good biocompatibility, could be a good candidate as a drug-eluting coating for magnesium-based stent.

Synthesis and Preparation of Cross-linked Films with Ester-Free Poly(trimethylene carbonate) Bearing Aromatic Urea Moiety

In an attempt to develop medical materials, a new design of ester-free poly(trimethylene carbonate) (PTMC) derivatives incorporating an aromatic pendant and urea moiety is explored. The aim of the present research study was to assess whether a flexible, elastic, and degradable PTMC film can promote the mechanical properties and perform better than commercially available PTMC. To tune the mechanical and thermal properties, two kinds of ratio with a cross-linker and a monomer were investigated, as well as the introduction of urea moieties. Both vinyl benzyl- and urea-based films showed thermal degradation with 10% weight loss (T10) of over 200 °C, which suggests the potential widespread use of the materials at a highly elevated temperature, such as in sterilization. The chemically modified PTMC films also have an improved glass transition temperature (Tg) up to 21 °C. Moreover, the incorporation of vinyl benzyl and the cross-linker markedly enhanced the elongation, tensile strength, and hydrolysis stability after 90 days. Although the materials showed slight deformation and stiffness, the urea-functionalized film has significant effects on the swelling degree. The present research demonstrates a facile modification approach for the development of ester-free TMC derivatives.

Synthesis of Doxorubicin-Loaded Nanobubble and Its Effect on Targeted Therapy for Patients with Ovarian Cancer

Nanomedicine has developed rapidly for improving the solubility of anti-cancer drugs, prolonging the circulation time in the body, and enhancing the accumulation in the lesion through the enhanced permeability and retention (EPR) effect. First, a new type of dithiolane trimethylene carbonate (MGN) was synthesized, and an amphiphilic polymer PEG-P (ERF-MGN) was synthesized based on MGN and trimethylene carbonate (ERF). Then, N-hydroxysuccinimide (NHS)-PEG-P (ERF-MGN) was prepared by further polymerizing NHS, which was amidated with polypeptide to obtain CC11-PEG-P (ERF-MGN). Finally, it was reacted with PEG-P (ERF-MGN) (mass ratio was 1:4), and CC11-PS was made by solvent exchange method. Through pH gradient method, doxorubicin (Dox) was loaded to prepare Dox nanobubble (CC11-PS-Dox). The prepared nanobubble was compared with the commonly utilized polyethylene glycol liposome Dox (Lipo-Dox) for tumor suppression, and CC11-PS-Dox had a relatively higher tolerated dose. After intravenous administration at a dose of 150 mg/kg, tumor growth in ovarian cancer mice bearing SKOV-3 was effectively inhibited, toxic and side effects were reduced, and the survival time of mice was dramatically increased (P < 0.05). In addition, CC11-PS-Dox was configured as a solution injected into patients with ovarian cancer, phosphate buffer saline (PBS) was injected as a control, and the tumor was irradiated with near-infrared laser (NIR). The tumor’s warming range was detected, and the tumor tissue was removed and stained with hematoxylin-eosin (HE) to observe the growth of the tumor. The results showed that CC11-PS-Dox + NIR can promote the tumor to heat up to 55 °C or more, while PBS + NIR can only promote the tumor to heat up to 37 °C. HE staining results showed that CC11-PS-Dox + NIR can promote tumor loss and cause cell damage. Therefore, it was verified that CC11-PS-Dox can be adopted for photothermal treatment of ovarian cancer.

Low-Molecular-Weight Aliphatic Polycarbonate-Based Polymer Electrolytes for Advanced High-Voltage Lithium Batteries

Solid-state batteries combining Li-metal anode and high-voltage cathodes are expected to be the key to surpass the limitations of current Li-ion batteries in terms of energy density, safety and lifetime.[1] However, finding successful solid polymer electrolytes (SPEs) for such high-energy batteries is utmost challenging. Poly(ethylene oxide) (PEO)-based materials was widely considered as promising candidates due to high safety, low cost, and excellent compatibility with lithium metal as well as lithium salts.[2] However, they have not satisfied the practical requirements due to (i) the high crystallinity of the ethylene oxide chains leading to insufficient ionic conductivity at low temperature and (ii) a very low Li+ transport number (t+~0.1-0.3).[3] Thus, the cells comprising PEO-based electrolytes must be operated at elevated temperatures (at least 60 °C). Furthermore, these PEO-based electrolytes are limited to a maximum anodic cut-off voltage of 3.9 V vs. Li|Li+, which prevents the use of high-voltage cathode materials like LiCoO2 (LCO) or Li[Ni0.6Co0.2Mn0.2]O2 (NCM622), etc., reversibly hosting lithium well above 4.0 V vs. Li|Li+.[4] For these reasons, much effort has been dedicated to developing alternative polymer systems.[5] Currently, aliphatic polycarbonates (APCs) and their copolymers have attracted much attention due to high dielectric constant, high Li+ transport number (t+>0.5), wide electrochemical stability window (ESW), etc.[6] However, it was found that the ionic conductivity and the electrochemical stability of these polymers are highly dependent on their molecular weight (MW) and synthesis method. Thus, high-MW APCs show an ESW up to 5.0 V vs. Li|Li+, but their ionic conductivity (~10−6-10−7 S cm−1 at 60 °C)[7] is far below the limit for practical application, which is around 10-4 S cm-1 at room temperature (RT). To increase the ionic conductivity, it is necessary to reduce the MW of the polymer to boost the segmental motion. As expected, APCs with lower MW showed significantly improved conductivity (~10−4-10−5 S cm−1 at RT). Unfortunately, they have much lower electrochemical stability (up to 4.0 V vs. Li|Li+)[8] probably derived from the increased number of OH groups at the end of polymer chains, which were determined as the limiting factor of polymer electrolytes due to their high reactivity with electrode materials.[9] Here we show that the electrochemical stability of Low-MW poly(trimethylene carbonate) (PTMC) and statistic copolymer of trimethylene carbonate and ε-caprolactone (PTMC-PCL copolymer) was remarkably improved via protecting these end-chain OH groups using two different protecting agents. The ester-protected PTMC and PTMC-PCL copolymer showed much improved lithium stripping/plating behavior due to higher stability with lithium anode while the urethane-protected ones are more stable towards oxidation at high potential (Figure 1). The obtained results reveal that the polymer electrolytes based on protected PTMC and PTMC-PCL copolymers are promising for high-energy lithium-metal batteries using high-voltage cathodes due to both high ionic conductivity and high electrochemical stability. Keyword: poly(trimethylene carbonate), PTMC, OH protection, polymer electrolyte, lithium battery References [1] A. Mauger, C. M. Julien, A. Paolella, M. Armand, K. Zaghib, Materials 2019, 12, 3892.[2] Z. Xue, D. He, X. Xie, J. Mater. Chem. A 2015, 3, 19218–19253.[3] W. Gorecki, M. Jeannin, E. Belorizky, C. Roux, M. Armand, J. Phys. Condens. Matter 1995, 7, 6823–6832.[4] J. Kalhoff, G. G. Eshetu, D. Bresser, S. Passerini, ChemSusChem 2015, 8, 2154–2175.[5] J. Mindemark, M. J. Lacey, T. Bowden, D. Brandell, Prog. Polym. Sci. 2018, 81, 114–143.[6] J. Zhang, J. Yang, T. Dong, M. Zhang, J. Chai, S. Dong, T. Wu, X. Zhou, G. Cui, Small 2018, 14, 1800821.[7] B. Sun, J. Mindemark, K. Edström, D. Brandell, Solid State Ionics 2014, 262, 738–742.[8] L. Meabe, N. Lago, L. Rubatat, C. Li, A. J. Müller, H. Sardon, M. Armand, D. Mecerreyes, Electrochim. Acta 2017, 237, 259–266.[9] X. Yang, M. Jiang, X. Gao, D. Bao, Q. Sun, N. Holmes, H. Duan, S. Mukherjee, K. Adair, C. Zhao, J. Liang, W. Li, J. Li, Y. Liu, H. Huang, L. Zhang, S. Lu, Q. Lu, R. Li, C. V. Singh, X. Sun, Energy Environ. Sci. 2020, 13, 1318–1325. Figure 1