- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Impact of Precise Control over Microstructure in Thiophene–Selenophene Copolymers
摘要： Controlling the sequence of repeat units in a synthetic polymer has been a long-standing topic of interest in chemistry. As methods to regulate sequence become more sophisticated, it is critical to consider how controlling the arrangement of repeat units along the polymer backbone impacts properties. In this work, thiophene?selenophene copolymers (statistical and periodic) were compared to elucidate the impact of periodicity on electronic properties and structural organization in conjugated macromolecules. Polymers were synthesized using catalyst-transfer polycondensation (CTP) enabling control over molecular weight and dispersity. The study revealed that optical bandgaps and redox potentials of periodic and statistical copolymers varied with composition in a predictable manner, regardless of monomer ordering along the chain. While the bandgaps of the two types of copolymers were indistinguishable, X-ray scattering revealed di?erences in solid-state packing. Both types of copolymers exhibited well-de?ned morphologies, but larger π-stacking distances and more orientational disorder were evident in the statistical systems. This indicates periodicity is an attribute that should be considered when synthesizing semiconducting materials.
关键词： solid-state packing,periodicity,electronic properties,thiophene?selenophene copolymers,catalyst-transfer polycondensation
更新于2025-09-10 09:29:36
-
Doxorubicin-loaded protease-activated near-infrared fluorescent polymeric nanoparticles for imaging and therapy of cancer
摘要： Despite significant progress in the field of oncology, cancer remains one of the leading causes of death. Chemotherapy is one of the most common treatment options for cancer patients but is well known to result in off-target toxicity. Theranostic nanomedicines that integrate diagnostic and therapeutic functions within an all-in-one platform can increase tumor selectivity for more effective chemotherapy and aid in diagnosis and monitoring of therapeutic responses. Material and methods: In this work, theranostic nanoparticles were synthesized with commonly used biocompatible and biodegradable polymers and used as cancer contrast and therapeutic agents for optical imaging and treatment of breast cancer. These core–shell nanoparticles were prepared by nanoprecipitation of blends of the biodegradable and biocompatible amphiphilic copolymers poly(lactic-co-glycolic acid)-b-poly-l-lysine and poly(lactic acid)-b-poly(ethylene glycol). Poly-l-lysine in the first copolymer was covalently decorated with near-infrared fluorescent Alexa Fluor 750 molecules. Results: The spherical nanoparticles had an average size of 60–80 nm. The chemotherapeutic drug doxorubicin was encapsulated in the core of nanoparticles at a loading of 3% (w:w) and controllably released over a period of 30 days. A 33-fold increase in near-infrared fluorescence, mediated by protease-mediated cleavage of the Alexa Fluor 750-labeled poly-l-lysine on the surface of the nanoparticles, was observed upon interaction with the model protease trypsin. The cytocompatibility of drug-free nanoparticles and growth inhibition of drug-loaded nanoparticles on MDA-MB-231 breast cancer cells were investigated with a luminescence cell-viability assay. Drug-free nanoparticles were found to cause minimal toxicity, even at high concentrations (0.2–2,000 μg/mL), while doxorubicin-loaded nanoparticles significantly reduced cell viability at drug concentrations .10 μM. Finally, the interaction of the nanoparticles with breast cancer cells was studied utilizing fluorescence microscopy, demonstrating the potential of the nanoparticles to act as near-infrared fluorescence optical imaging agents and drug-delivery carriers. Conclusion: Doxorubicin-loaded, enzymatically activatable nanoparticles of less than 100 nm were prepared successfully by nanoprecipitation of copolymer blends. These nanoparticles were found to be suitable as controlled drug delivery systems and contrast agents for imaging of cancer cells.
关键词： enzymatic activation,nanoprecipitation,theranostics,PEG,poly-l-lysine,PLGA,block copolymers,nanomedicine,fluorescence imaging,drug delivery,nanoparticles,PLA
更新于2025-09-10 09:29:36
-
Visible Light-Driven MADIX Polymerisation via a Reusable, Low-Cost and Non-Toxic Bismuth Oxide Photocatalyst
摘要： The continuous amalgamation of photocatalysis into existing reversible deactivation radical polymerisation processes has initiated a rapidly propagating area of polymer research in recent years. We introduce bismuth oxide (Bi2O3) as a heterogeneous photocatalyst for polymerisations, operating at room temperature with visible light. We demonstrate formidable control over degenerative chain-transfer polymerisations, such as macromolecular design by interchange of xanthate (MADIX) and reversible addition-fragmentation chain transfer (RAFT) polymerisation. We achieved narrow molecular weight distributions and attribute the excellent temporal control to a photo-induced electron transfer (PET) process. This methodology was employed to synthesise diblock copolymers combining differently activated monomers. The Bi2O3 catalyst system has the additional benefits of low toxicity, reusability, low-cost, and ease of removal from the reaction mixture.
关键词： polymerisation,photochemistry,block copolymers,RDRP,PET-RAFT
更新于2025-09-10 09:29:36
-
Visible Light-Driven MADIX Polymerisation via a Reusable, Low-Cost and Non-Toxic Bismuth Oxide Photocatalyst
摘要： The continuous amalgamation of photocatalysis into existing reversible deactivation radical polymerisation processes has initiated a rapidly propagating area of polymer research in recent years. We introduce bismuth oxide (Bi2O3) as a heterogeneous photocatalyst for polymerisations, operating at room temperature with visible light. We demonstrate formidable control over degenerative chain-transfer polymerisations, such as macromolecular design by interchange of xanthate (MADIX) and reversible addition-fragmentation chain transfer (RAFT) polymerisation. We achieved narrow molecular weight distributions and attribute the excellent temporal control to a photo-induced electron transfer (PET) process. This methodology was employed to synthesise diblock copolymers combining differently activated monomers. The Bi2O3 catalyst system has the additional benefits of low toxicity, reusability, low-cost, and ease of removal from the reaction mixture.
关键词： polymerisation,photochemistry,block copolymers,RDRP,PET-RAFT
更新于2025-09-10 09:29:36
-
Optical oxygen sensors based on microfibers formed from fluorinated copolymers
摘要： Polymeric micro?bers, particularly the ?uorinated copolymers’ ?bers, are promising functional materials for photoelectric devices, sensing, and energy storage due to their various surface characteristics. However, to obtain the high ?uorine content copolymer-based ?bers with considerable uniformity is likely to be especially challenging, which seriously debilitates their applications in sensor devices. Herein, for the ?rst time, we presented a high ?uorine content platinum porphyrin-grafted poly(isobutyl methacrylate-co-dodeca?uoroheptyl methacrylate) copolymers (PtTFPP-p(IBM-co-DFHMA)) micro?brous thin-?lms used as optical oxygen sensors. The porous thin-?lm frameworks were formed of uniform micro?bers, which a?orded an exceptional improvement in sensitivity and exhibited 584% higher sensitivity than the solid sensing ?lm owing to the large speci?c surface area, porous structures and oxygen di?usion enhancement by ?uorine elements. Additionally, the remarkable emission intensity-changing characteristic of the micro?ber sensing ?lm under various air pressures facilitates convenient visualization of pressure distributions on ?lm surface. The characteristics are particularly important for the computational ?uid dynamics simulations in various sensing ?elds such as unsteady ?ow visualization and unsteady pressure measurements, etc. Owing to its attractive advantages and versatile performance, ?uorine-containing copolymers ?bers are expected to provide a new strategy for the rational design of high performance gas sensor devices.
关键词： PSP,Micro?ber,Fluorinated copolymers,Electrospinning,Oxygen sensor
更新于2025-09-10 09:29:36
-
DOX/ICG-carrying γ-PGA-g-PLGA-based polymeric nanoassemblies for acid-triggered rapid DOX release combined with NIR-activated photothermal effect
摘要： To boost the efficacy of chemo-photothermal cancer treatment by the intracellular rapid release of doxorubicin (DOX) combined with near-infrared (NIR)-triggered photothermal effect of indocyanine green (ICG), the poly(γ-glutamic acid)-g-poly(lactic-co-glycolic acid) (γ-PGA-g-PLGA)-based polymeric nanoassemblies (PNAs) with simultaneous incorporation of DOX and ICG were developed in this work by simple one-step nanoprecipitation. The obtained DOX/ICG-loaded PNAs were characterized by a compact γ-PGA/DOX complexes-encapsulated PLGA-rich core covered with the co-assembly of amphiphilic D-α-tocopheryl polyethylene glycol succinate (TPGS), 1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)] (DSPE-PEG) and ICG molecules. The robust cargo-loaded PNAs not only promoted the photo-stability of ICG in PBS, but also reduced ICG leakage from PNAs. With the milieu pH being altered from 7.4 to 5.0, the massive disruption of ionic DOX/γ-GA complexes and PLGA degradation considerably accelerated DOX release from payload-containing PNAs. The results of in vitro cellular uptake revealed that the DOX/ICG-loaded PNAs appreciably enhanced the cellular uptake of payloads by HeLa cells. Notably, through the intracellular acid-triggered rapid DOX release combined with the ICG-based NIR-activated hyperthermia and singlet oxygen generation, the combination therapy of DOX/ICG-loaded PNAs can use lower dosage of drugs to effectively inhibit proliferation of HeLa cells compared to the chemo or photothermal treatment alone, thus showing the great potential to improve efficacy of cancer treatment.
关键词： polymeric nanoassemblies,pH-triggered DOX release,NIR-activated photothermal treatment,amphiphilic graft copolymers,intracellular drug delivery
更新于2025-09-09 09:28:46
-
Electrochromism of novel triphenylamine-containing polyamide polymers
摘要： A series of novel polymers (coded as BCT-1 to BCT-6 (BTC is block triphenylamine)) based on N1-(4-aminophenyl)-N1-phenyl benzene-1,4-diamine, pyridine-2,6-dicarboxylic acid, 4,40-(phenyl azanediyl)dibenzoic acid (PDA), and different diamine compounds were synthesized successfully through a polymer condensation reaction. For comparison, model polymers, BCT–2,6-pyridine dicarboxylic acid (PA) and BCT–PDA, were synthesized as well. The electrochromic properties of the BCTs were determined via an electrochemical workstation and a UV–visible spectrophotometer. Through electrooxidation, the polymer ?lms showed reversible redox processes and steady color changes. In a comparision of the electrochromic characteristics of the BCTs, almost all the novel polymer ?lms showed a better electrochromism stability, a higher electrochromic coloration ef?ciency (CE), and a more rapid switching time than BCT–PA and BCT–PDA. Among these polymers, BCT-1 exhibited the highest CE of 266.7 cm2/C, and BCT-4 showed the most rapid switching time (color switching time = 3.08 s and bleaching time = 2.01 s). ? 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 136, 47264.
关键词： electrochemistry,copolymers,polyamides,optical properties
更新于2025-09-04 15:30:14
-
Manganese phosphinocarbodithioate for RAFT polymerisation with sunlight-induced chain end post-treatment
摘要： A new manganese RAFT agent of the formula Cp(CO)2MnP(Ph)2C(vS)SCH(CH3)Ph was synthesized in a good overall yield by a three-step reaction from cymantrene and diphenylphosphine as the main starting materials. This complex proved to be e?cient for the control of RAFT polymerisation of St, n-BA and DMAAm. The reaction course could be conveniently monitored by 31P NMR spectroscopy. The controlled character of these polymerisations and the integrity of the polymer chain ends were demonstrated by the synthesis of diblock copolymers of St and n-BA. In the case of long polymerisation times (i.e. for PSt), photo-induced polymer chain coupling reactions were detected. Importantly, removal of the Mn-RAFT-ω-chain end by visible light irradiation led to the formation of a monomodal SH-terminated PSt. These phenomena were evidenced by IR spectroscopy, SEC with RI and UV detection modes and by ESI mass spectrometry.
关键词： sunlight-induced chain end post-treatment,visible light irradiation,manganese phosphinocarbodithioate,RAFT polymerisation,diblock copolymers
更新于2025-09-04 15:30:14