查找使用阿拉丁产品的科研文献

Enhancing interfacial strength of epoxy resin composites via evolving hyperbranched amino-terminated POSS on carbon fiber surface

Lichun Ma,Yingying Zhu,Mengzhu Wang,Xiaobing Yang,Guojun Song,Yudong Huang

A self-synthesized octa(γ-chloropropyl) polyhedral oligomeric silsesquioxanes (POSS) and its evolutionary amino-terminated hyperbranched structure were introduced onto the carbon fibers (CFs) surface (CF-G n -POSS-NH 2 , n  = 1, 2 and 3) by chemically and successively grafting method to improve the interfacial properties of CFs/epoxy composite. The fiber surface structures could be tuned through regulating grafting generation ( n ) of CF-G n -POSS-NH 2 , and the polarity and roughness of CF surface increased with the incremental dendritic generation number. Interfacial shear strength (IFSS), interlaminar shear strength (ILSS) and dynamic mechanical properties of the functionalized CFs composites improved as the grafting generation increased, which may be attributed to the varying degrees of chemical interaction, mechanical interlocking and resin wettability provided by hyperbranched G n -POSS-NH 2 interface. Moreover, the interfacial structure has been also speculated and analyzed.

Synthesis and self-assembly behavior of pH-responsive star-shaped POSS-(PCL-P(DMAEMA-co-PEGMA))16 inorganic/organic hybrid block copolymer for the controlled intracellular delivery of doxorubicin

Lei Li,Beibei Lu,Qikui Fan,Jianning Wu,Lulu Wei,Jun Hou,Xuhong Guo,Zhiyong Liu

In this work, well-defined amphiphilic polyhedral oligomeric silsesquioxane (POSS) star-shaped inorganic/organic hybrid block copolymers with poly(ε-caprolactone)-poly(2-(dimethylamino)ethyl methacrylate)-co-poly(ethylene glycol) methacrylate (POSS-PCL-P(DMAEMA-co-PEGMA))16 were synthesized with different PCL segments via thiol-ene click reaction, ring opening polymerization (ROP) and atom transfer radical polymerization (ATRP), which were confirmed by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance (1H NMR), gel permeation chromatography (GPC), X-ray photoelectron spectroscopy (XPS) and thermogravimetric analysis (TGA). Subsequently, the polymers could self-assemble into micelles in aqueous solution, which were investigated by dynamic light scattering (DLS), ultraviolet-visible spectroscopy (UV-vis) and transmission electron microscopy (TEM). The pH-responsive self-assembly behavior of these triblock copolymers in water was investigated at different pH values of 5.0 and 7.4 for controlled doxorubicin release; the results indicated that the release rate of DOX could be effectively controlled by altering the pH and the release of drug loading efficiency (DLE) was up to 82% (w/w). Furthermore, CCK-8 assays and confocal laser scanning microscopy (CLSM) against HeLa cells indicated that the micelles had no associated cytotoxicity, possessed good biodegradability and biocompatibility, and identified the location of the DOX in HeLa cells. The DOX-loaded micelles could easily enter the cells and produce the desired pharmacological action, and minimize the side effects of free DOX. Moreover, these flexible micelles with on-off switched drug release may offer a promising method to deliver a wide variety of hydrophobic payloads to tumor cells for cancer therapy.

3D-printed porous PEEK scaffold combined with CSMA/POSS bioactive surface: A strategy for enhancing osseointegration of PEEK implants

Zhewen Liu,Mei Zhang,Zihang Wang,Yilong Wang,Wenying Dong,Wendi Ma,Shanshan Zhao,Dahui Sun

As an attractive biomaterial for orthopedic implants , polyetheretherketone (PEEK) has many prominent characteristics such as good biocompatibility and biomechanical properties , as well as natural radiolucency. However, the potential clinical application is limited due to its biologically inert surface and poor osseointegration. To solve this problem, we fabricate a macroporous PEEK scaffold modified with methacrylated chitosan/polyhedral oligomeric silsesquioxane (CSMA/POSS) nanocomposite through 3D printing , sulfonation and UV-induced graft polymerization. The water contact angle, protein adsorption ability and biomineralization study of the sulfonation-treated PEEK (SPEEK)-CSMA/POSS scaffolds were measured in order to evaluate the surface properties. The results indicated that CSMA/POSS as a bioactive microporous surface integrated with nanoparticles promoted the protein adsorption and apatite formation. For the in vitro and in vivo evaluation of the osteogenicity, rat bone marrow mesenchymal stem cells (rBMSCs) and rat calvaria defect repair model were used. Biological results showed that the 3D porous structure and bioactive surface of modified PEEK scaffolds provided a suitable condition for cell adhesion and proliferation, enhanced the osteogenic differentiation of rBMSCs and promoted osteogenesis in vivo compared to the untreated PEEK scaffold. Therefore, 3D-printed macroporous PEEK scaffold modified with CSMA/POSS bioactive microporous surface represents a promising modification strategy for enhancing osseointegration of PEEK implants.

Dual Stimuli-Responsive Hybrid Polymeric Nanoparticles Self-Assembled from POSS-Based Starlike Copolymer-Drug Conjugates for Efficient Intracellular Delivery of Hydrophobic Drugs

Qingqing Yang,Lian Li,Wei Sun,Zhou Zhou,Yuan Huang

To further fine tune drug release and enhance therapeutic effects of polyhedral oligomericsilsesquioxane (POSS)-based nanomedicine, a starlike organic–inorganic conjugate was synthesized by grafting semitelechelic N-(2-hydroxypropyl) methacrylamide (HPMA) copolymers to a POSS rigid core through reductively degradable disulfide bonds. The hydrophobic docetaxel (DTX) was attached to the grafts by pH-sensitive hydrazone bonds and also encapsulated into the POSS core (SP-DTX). Thus, the final amphiphilic star-shaped conjugates could self-assemble into nanoparticles and exhibited conspicuous drug-loading capacity (20.1 wt %) based on the covalently conjugated accompanied by physically encapsulated DTX. The stimuli-responsive DTX release under acidic lysosomal and reducing cytoplasmic environments was verified, leading to enhanced cytotoxicity against PC-3 human prostate carcinoma cells. To evaluate the in vivo therapeutic effects of the DTX-loaded nanovehicles objectively, a stroma-rich, prostate xenograft tumor model was generated. SP-DTX displayed uniform tumor distribution and suppressed tumor growth to a more pronounced level (tumor inhibition of 78.9%) than nonredox-sensitive SP-DTX-A (67.4%), SP-DTX-C contained DTX only in the core (65.5%) or linear P-DTX (60.7%) through enhanced depletion of cancer-associated fibroblasts and induction of apoptosis. The hybrid POSS-based polymeric nanoparticles offer an efficient approach to transport hydrophobic drugs for cancer therapy.

POSS-based poly(aryl ether sulfone)s random terpolymer linked POSS to the main chain: effect of chemical structure and POSS content on properties

Yanfeng Wei,Qiyang Jiang,Jinmeng Hao,Jianxin Mu

In order to investigate the effect of polyhedral oligomeric silsesquioxane content and the structure-function related on the dielectric property and hydrophobicity, three kinds of poly(aryl ether sulfone)s (PAESs) random terpolymer with different chemistry structure at variable polyhedral oligomeric silsesquioxane content in the main chain are prepared. The structures of PAESs are characterized by infrared (IR), nuclear magnetic resonance (NMR), and wide-angle X-ray diffraction (WXRD) spectra. The results show that the dielectric constant initially increases then decrease to 2.68 at 100%-double-decker silsesquioxane (DDSQ)-PAES(molar content of DDSQ = 100%) at 1 MHz. The contact angle increased to 97.5° at 100%-DDSQ-PAES. While the chemical structure of organic chains also plays an important role on thermostability, dielectric, and hydrophobic properties. The results are discussed and interpreted in detail. Copyright © 2016 John Wiley & Sons, Ltd.

Novel POSS unimolecular micelles for drug delivery

Yucheng Sun,Longyu Tian,Zaijun Lu

This study developed unimolecular micelles featuring a polyhedral oligomeric silsesquioxane (POSS) core and eight arms by reacting POSS with the block copolymer mPEG- b -PCL, which were utilized as a drug delivery platform. Compared to conventional self-assembled polymeric micelles, POSS unimolecular micelles exhibit precise dimensions and are monodisperse. They lack a critical micelle concentration (CMC) and can maintain stability in physiological environments with varying concentrations and pH levels. The POSS unimolecular micelles are constructed using biocompatible materials, specifically polycaprolactone and polyethylene glycol. POSS features a rigid cage-like structure along with multifunctional group characteristics, which serve as a stable core for unimolecular micelles. This significantly enhances both the drug-loading capacity and thermodynamic stability of the micelles, rendering them suitable for applications in physiological environments. POSS unimolecular micelles can encapsulate the anticancer drug doxorubicin, offering enhanced stability and prolonged drug release time compared to conventional polymer micelles, thereby providing a sustained-release effect.

Reversible thermochromic POSS-Metal Films for early warning

Yaoyuan Xu,Lingyun Huang,Jun Long,Runze Zhang,Zhengxiang Zhong,Ling Yang,Li Liu,Yudong Huang

Due to the unique ability to change color promptly when temperature fluctuates, the reversible thermochromic film plays an important role in reducing the occurrence of fire accidents. It can be used into the early warning of fire and behaves as an indispensable part in constructing fire prevention system. In this paper, a series of novel reversible thermochromic POSS-Metal Films (abbreviated as PMFs) with different ratio of POSS (octa-aminopropyl POSS) and metal salt [Cr(NO 3 ) 3 ·9H 2 O] were prepared via a simple method. The PMFs not only exhibit excellent thermal-stability and repeatability, but also are capable of changing color rapidly within a few seconds as the temperature rises, possessing a superior warning effect of prompt color change. The thermochromic mechanism of PMFs is also elucidated by TG-MS, Variable temperature infrared test and Variable temperature X-ray electron diffraction , which explains its discoloration. With temperature increasing, ligands (H 2 O and NO 3 − ) were decomposed and released from PMFs, resulting in the color change of PMFs. When the temperature decreased, the water molecules in the air could be captured into re-coordination with PMFs, making it recover its original color. The remarkable color change of PMFs makes it play an important role in the early warning of fire, providing us with a novel way in fire detection.

Hepta(3,3,3-trifluoropropyl) Polyhedral Oligomeric Silsesquioxane-capped Poly(N-isopropylacrylamide) Telechelics: Synthesis and Behavior of Physical Hydrogels

Lei Wang,Ke Zeng,Sixun Zheng

Hepta(3,3,3-trifluoropropyl) polyhedral oligomeric silsesquioxane (POSS)-capped poly(N-isopropylacrylamide) (PNIPAAm) telechelics with variable lengths of PNIPAAm midblocks were synthesized by the combination of reversible addition−fragmentation chain transfer polymerization (RAFT) and the copper-catalyzed Huisgen 1,3-cycloaddition (i.e., click chemistry). The POSS-capped trithiocarbonate was synthesized and used as the chain transfer agent for the RAFT polymerization of N-isopropylacrylamide. The organic−inorganic amphiphilic telechelics were characterized by means of nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). Atomic force microscopy (AFM) shows that all the POSS-capped PNIPAAm telechelics exhibited microphase-separated morphologies, in which the POSS terminal groups were self-assembled into the microdomains and dispersed into the continuous PNIPAAm matrices. The POSS nanodomains could behave as the physical cross-linking sites and as a result the physical hydrogels were formed while these POSS-capped PNIPAAm telechelics were subjected to the solubility tests with water. These physical hydrogels possessed well-defined volume phase transition phenomena and displayed rapid reswelling and deswelling thermoresponsive behavior compared to control PNIPAAm hydrogel.

Polyurethane/POSS nanocomposites for superior hydrophobicity and high ductility

Hui Zhao,Wei She,Dean Shi,Wei Wu,Qun-chao Zhang,Robert K.Y. Li

Abstarct A novel polyhedral oligomeric silsesquioxane with di-hydroxyl and two triethoxy groups (m-POSS) was synthesized by a facile method. Then it reacted with diisocyanate to prepare aqueous polyurethane (APU)/m-POSS nanocomposites. The di-hydroxyl groups facilitating the m-POSS dispersing into the main chain of the APU, during which two triethoxy groups served as cross-linking sites. The addition of m-POSS had little influence on the viscosity and stability of the APU/m-POSS dispersions. The APU/m-POSS nanocomposite film with 8 wt% m-POSS exhibited superior surface hydrophobicity with water contact angle up to 121° due to the migration of Si element from inner to the surface. Moreover, the Young's modulus and tensile strength of APU/m-POSS composite increased up to 21.8 MPa and 15.3 MPa, respectively, with the elongation at break increased up to 1000%, which was ascribed to the enhancement of the cross-linked m-POSS. The DMA results revealed that the glass transition temperature ( T g ) of the APU hard segment increased significantly while a little change was observed for that of soft segments, indicating that the m-POSS preferred to locate in the APU as hard segments. This functionalized m-POSS can endow polymer matrix with superior hydrophobicity and enhanced mechanical properties.

Click-Chemistry Approach toward Antibacterial and Degradable Hybrid Hydrogels Based on Octa-Betaine Ester Polyhedral Oligomeric Silsesquioxane

Jin Han,Qinyue Chen,Yupeng Shen,Zhixiong Liu,Xiaoyu Hao,Mingqiang Zhong,Zhengping Zhao,Michael R. Bockstaller

An efficient process for the synthesis of degradable hydrogels containing octa-betaine ester polyhedral oligomeric silsesquioxane (POSS) through efficient thiol–ene and Menschutkin click reactions was developed. The hydrogels exhibited a yield strength of 0.36 MPa and a compressive modulus of 4.38 MPa and displayed excellent flexibility as well as torsion resistance. Antibacterial efficacy of hydrogels (and degradation products) was evaluated using Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive). Efficacy was found to increase with the concentration of cetyl chloroacetate (CCA) in the hydrogel network, reaching 93% and 99% for Escherichia coli and Staphylococcus aureus, respectively. Degradation of hydrogels was observed in weak alkali conditions (pH = 8) and at physiological conditions (pH = 7.4). The degradation time of the hydrogels could be finely tuned by variation of the CCA content in the hydrogel and environmental stimulus. The tunable degradation behavior under physiological conditions combined with high antibacterial efficacy could render the presented materials interesting for tissue engineering applications.

Core–shell octa(azidopropyl) POSS–PEO micelle via “click” chemistry

Yujing Li,Liqiang Wan,Farong Huang,Lei Du

An amphiphilic OAPS–PEO was synthesized by “click” reaction between octa(azidopropyl) POSS (OAPS) and propargyl-terminated PEO . The structure of OAPS–PEO was characterized by nuclear magnetic resonance (NMR). The amphiphilic properties and aggregation process of OAPS–PEO in aqueous solution were investigated by fluorescence, dynamic and static light scattering (DLS and SLS), and transmission electron microscopy (TEM). The critical aggregates concentration was determined at ~   0.10   mg/mL using fluorescence measurements. At this concentration, unassociated unimolecular micelles with diameter size of 40–50   nm were found by DLS, and were also studied by means of TEM. At a lower concentration, all the OAPS–PEO self-assembled into loose balls. With the increase of the OAPS–PEO polymer concentration , OAPS centralizes to be the core of the aggregates. At the concentration of 2.0   mg/mL, aggregates present to be a core–shell structure.

POSS-based glycidyl methacrylate copolymer for transparent and permeable coatings

Yanli Ma,Ling He,Lingru Zhao,Aizhao Pan