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107. Biomimetic Strategies for Electrophoretic Deposition of Polymers and Composites

Author

Zhao, Qinfu, Zhitomirsky, Igor, Veldhuis, Stephen, and Materials Science and Engineering

Subjects
Corrosion protection, Composite films, Polymer films, Biosurfactant, Electrophoretic deposition, Bile acids
Abstract

The global market for fluoropolymers, including polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), and poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), is growing rapidly due to their copious applications in the construction, automotive, medical, chemical, and electrical industries. Fluoropolymers owe their popularity partly to their excellent chemical and thermal stability and useful mechanical, piezoelectric, and ferroelectric properties. They are made into films or coatings that are used for corrosion protection or surface property enhancement. Electrophoretic deposition (EPD) has generated increasing interest in manufacturing advanced films for various applications due to its low cost, versatility, simple apparatus, and good film quality compared with other deposition techniques like dip coating, spin coating, electrospinning, or spay coating. Moreover, EPD facilitates uniform deposition on the substrates of complex shapes at a high deposition rate. The aim of this research is to develop novel biomimetic strategies for fabricating polymer films and their composite films with multifunctional particles through EPD. This method involves the electrophoresis of charged particles in a stable colloidal suspension towards an electrode, forming deposition. Fluoropolymers, however, are electrically neutral and chemically inert, and their EPD presents difficulties. Therefore, successful EPD depends on understanding how to modify the surface of polymer particles using advanced biosurfactants to impart charge and form a well dispersed, stable colloidal suspension. One strategy is to leverage the unique dispersing power of bile acids and salts as biosurfactants for EPD of PTFE and PVDF films and composite films. When doing so, it was found that the amphiphilic structure of bile salts such as sodium deoxycholate (DChNa) facilitated adsorption on the chemically inert, hydrophobic surfaces of PTFE, diamond, and carbon dots. In this strategy, DChNa acted as a charging, dispersing, film-forming agent for the co-deposition of PTFE composite films from an aqueous suspension. Water insoluble bile acids (BAs) were found to be biosurfactants for the EPD of PTFE and PVDF from organic solvents, in which lithocholic acid (LCA) was used as a co-dispersant for the fabrication of composite PTFE-diamond coatings and PTFE coatings provided corrosion protection for stainless steel in 3% NaCl solutions. The dispersing performance of four other bile acids, chenodeoxycholic acid (CDCA), deoxycholic acid (DCA), ursodeoxycholic acid (UDCA), and cholic acid (ChA), was analyzed and compared with LCA on the deposition performance of PVDF. It was found that the PVDF deposition yield obtained using different BAs increased in the order of LCA

Published
2022

110. Colloidal processing of ferroelectric poly(vinylidene fluoride-co-hexafluoropropylene)—ferrimagnetic pseudocapacitive CuFe2O4 composite films.

Author

Zhao, Qinfu, Liu, Xinqian, Veldhuis, Stephen, and Zhitomirsky, Igor

Subjects
DIFLUOROETHYLENE, FERROELECTRIC polymers, COLLOIDAL suspensions, ELECTROPHORETIC deposition, POLYMERS, ELECTRIC capacity, MICROSTRUCTURE
Abstract

Composite polymer-ceramic films are prepared from colloidal suspensions by electrophoretic deposition (EPD). Co-deposition of ferrimagnetic CuFe2O4 with ferroelectric poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP) polymer is achieved using a co-dispersant, which is also used for the preparation of PVDF-HFP particles. The mechanism of co-dispersant adsorption on CuFe2O4 and PVDF-HFP in colloidal suspensions is analyzed. Electrochemical studies of CuFe2O4 reveal good pseudocapacitive properties of this material in a negative potential range, which make it a material of choice for magnetocapacitive devices. A capacitance of 1.72 F cm−2 (43.1 F g−1) is observed at 2 mV s−1 for pure material in a neutral Na2SO4 electrolyte. The microstructure and composition of PVDF-HFP-CuFe2O4 films are analyzed. Composite films show ferrimagnetic properties, which are analyzed in a wide temperature range. EPD method represents a versatile strategy for the fabrication of composite films based on functional properties of CuFe2O4 and PVDF-HFP. [ABSTRACT FROM AUTHOR]

Published
2022
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113. Au Catalyzing Control Release NO in vivo and Tumor Growth-Inhibiting Effect in Chemo-Photothermal Combination Therapy

Author

Zhang,Ying, Zhou,Tianfu, Li,Jian, Xu,Nuo, Cai,Mingze, Zhang,Hong, Zhao,Qinfu, Wang,Siling, Zhang,Ying, Zhou,Tianfu, Li,Jian, Xu,Nuo, Cai,Mingze, Zhang,Hong, Zhao,Qinfu, and Wang,Siling

Abstract

Ying Zhang,1 Tianfu Zhou,1 Jian Li,1 Nuo Xu,1 Mingze Cai,1 Hong Zhang,2 Qinfu Zhao,3 Siling Wang3 1Key Laboratory of TargetDrug Design and Research, Ministry of Education, Shenyang Pharmaceutical University, Shenyang, 110016, People’s Republic of China; 2Van ’T Hoff Institute for Molecular Sciences, University of Amsterdam, Amsterdam, 1098 XH, the Netherlands; 3Department of Pharmaceutics, School of Pharmacy, Shenyang Pharmaceutical University, Shenyang, 110016, People’s Republic of ChinaCorrespondence: Qinfu Zhao; Siling Wang Tel/Fax +86 24 43520555Email qinfuzhao@syphu.edu.cn; silingwang@syphu.edu.cnIntroduction: Aim to obtain a NO donor that can control released NO in vivo with the high efficacy of tumor suppression and targeting, a nanoplatform consisting of FA-Fe3O4@mSiO2-Au/DOX was constructed.Methods: In vitro, the nanoplatform catalyzed NO’s release with the maximum value of 4.91 μM within 60 min at 43°C pH=5.0, which was increased by 1.14 times when the temperature was 37°C. In vivo, 11.7 μg Au in the tumor tissue was found to catalyze S-nitrosoglutathione continuously, and 54 μM NO was checked out in the urine.Results and Discussion: The high concentration of NO was found to increase the apoptotic rate and to reduce tumor proliferation. In the chemo-photothermal combination therapy, the tumor inhibition rate was increased up to 94.3%, and Au’s contribution from catalyzing NO release NO was 8.17%.Keywords: thermotherapy, chemotherapy, NO control release, magnetic mesoporous silica nanocomposites

Published
2021

114. A comprehensive study of Al0.6Ti0.4N coatings deposited by cathodic arc and HiPIMS PVD methods in relation to their cutting performance during the machining of an inconel 718 alloy

Author

Natural Sciences and Engineering Research Council of Canada, Reolon, Luca W., Aguirre, Myriam H., Yamamoto, Kenji, Zhao, Qinfu, Zhitomirsky, Igor, Fox-Rabinovich, German, Veldhuis, Stephen Clarence, Natural Sciences and Engineering Research Council of Canada, Reolon, Luca W., Aguirre, Myriam H., Yamamoto, Kenji, Zhao, Qinfu, Zhitomirsky, Igor, Fox-Rabinovich, German, and Veldhuis, Stephen Clarence

Abstract

The structural, physical–chemical, and micromechanical characteristics of Al0.6Ti0.4N coatings deposited by different physical vapor deposition (PVD) methods, such as cathodic arc deposition (CAD), as well as advanced HiPIMS techniques were investigated in terms of their cutting performance during the machining of an Inconel 718 alloy. XRD studies had revealed that the HiPIMS coating featured lower residual stresses and more fine-grained structure. Electrochemical characterization with the potentiostat-impendence method shows that the HiPIMS coating has a significantly lower porosity than CAD. SEM and AFM studies of the surface morphology demonstrate that the HiPIMS coating has a smoother surface and an absence of droplet phases, in contrast with CAD. XRD, combined with FIB/TEM studies, shows a difference in the crystal structure of both coatings. The micromechanical characteristics of each coating, such as hardness, elastic modulus, fracture toughness, and adhesion to the substrate, were evaluated. The HiPIMS coating was found to possess a more beneficial combination of micromechanical properties compared to CAD. The beneficial characteristics of the HiPIMS coating alleviated the damage of the coated layer under operation. Combined with grain size refinement, this results in the improved adaptive performance of the HiPIMS coating through the formation of a greater amount of thermal barrier sapphire tribo-films on the friction surface. All of these characteristics contribute to the reduction of flank and crater wear intensity, as well as notching, leading to an improvement of the HiPIMS coating’s tool life.

Published
2021

121. Feasibility and Safety of Cervical Kinematic Magnetic Resonance Imaging in Patients with Cervical Spinal Cord Injury without Fracture and Dislocation

Author

Bao, Yongzheng, primary, Zhong, Xueren, additional, Zhu, Wengang, additional, Chen, Yu, additional, Zhou, Longze, additional, Dai, Xiangheng, additional, Liao, Junjian, additional, Li, Zhong, additional, Hu, Konghe, additional, Bei, Kangsheng, additional, Xiong, Yinghui, additional, Hu, Yongyu, additional, Zhao, Qinfu, additional, Zhu, Zhouxing, additional, Yu, Yanli, additional, Wu, Qiang, additional, and Xi, Xinhua, additional

Published
2020
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123. A theoretical study of the electrochemical reduction of CO2 on cerium dioxide supported palladium single atoms and nanoparticles.

Author

Guo, Yannv, Zhu, Haiyan, Zhao, He, Zhao, Qinfu, Zhou, Caihua, Suo, Bingbing, Zou, Wenli, Jiang, Zhenyi, and Li, Yawei

Abstract

Pd/CeO2 catalysts show superior catalytic performance owing to their optimal cycling activity and stability. In this study, single-atom Pd and eight-atom Pd nanoparticle clusters were supported on the surface of CeO2(110) to investigate the effect of loaded-metal size on the catalytic performance of the Pd–CeO2 system for CO2 reduction. We investigated the CO2 reduction reaction (CRR) that produces C1 products (CO, HCOOH, CH3OH, and CH4) on Pd8/CeO2 and Pd/CeO2 by density functional theory. The structures, CO2 adsorption configurations, and CO2 reduction mechanisms of these two electrocatalysts were systematically studied. Subsequently, different reduction pathways on Pd8/CeO2 and Pd/CeO2 were investigated to identify the optimal reaction pathway for further assessment. The results showed that both of these catalysts are more selective towards the production of CH3OH than CH4. Moreover, compared to Pd/CeO2 and Pd4/CeO2 (from a previously reported study) the production of CH3OH via the CRR on Pd8/CeO2 exhibited the lowest limiting potential. These results demonstrate the superiority of Pd8/CeO2 as an electrocatalyst for the electrochemical reduction of CO2 to CH3OH. [ABSTRACT FROM AUTHOR]

Published
2021
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128. Highly Selective Electrocatalytic CO2 Reduction to Methanol on Iridium Dioxide with CO* Spectators.

Author

Zhao, He, Zhu, Haiyan, Feng, Yifan, Zhao, Qinfu, Suo, Bingbing, Zou, Wenli, Han, Huixian, Zhai, Gaohong, Jiang, Zhenyi, Song, Qi, and Li, Yawei

Subjects
IRIDIUM oxide, METHANE, DENSITY functional theory, METHANOL, METHANOL production, CATALYTIC reduction
Abstract

Iridium dioxide has emerged as a promising anode family for electrocatalytic reduction of CO2. Herein, the catalytic mechanism of CO2 reduction reaction (CO2RR) on the IrO2 (110) electrocatalyst model has been assessed using density functional theory (DFT) calculations. The CO* spectator on the IrO2 (110) is the crucial factor, which directly affects the binding free energy of the reaction intermediates by means of the different ratios of CO* spectator models. Our results showed that the CO* spectator may have a great promotion effect on the methanol production, and it always maintains low sensitivity on the CO2 reduction to methane reaction. The onset potentials for reducing to methanol and methane are −0.32 V‐RHE and −0.68 V‐RHE, respectively, at a CO* coverage of 50 %, which means that providing an appropriate CO* coverage can improve the selectivity of CO2 catalytic reduction to methanol tremendously. It is worth noting that the intermediate CH3O*+OH*, which plays a vital role in the major pathways to produce methanol and methane, is a branch point that led to the formation of two products. Although both subsequent protonation processes are exothermic, the path to methanol production is more favorable than that of CH4 formation. These results demonstrate that iridium dioxide should be a good CO2RR catalyst, and the CO* spectator also exhibits an enhanced effect on the selectivity of CO2 reduced to alcohol products. [ABSTRACT FROM AUTHOR]

Published
2020
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141. CO2 Adsorption on the B12N12 Nanocage Encapsulated with Alkali Metals: A Density Functional Study.

Author

Liang, Ximin, Zhang, Qiyan, Zhao, Qinfu, Zhao, He, Feng, Yifan, Suo, Bingbing, Han, Huixian, Song, Qi, Li, Yawei, Zou, Wenli, and Zhu, Haiyan

Subjects
ALKALI metals, ADSORPTION capacity, PHYSISORPTION, CHEMICAL processes, DENSITY functional theory, ADSORPTION (Chemistry), CHEMICAL bond lengths
Abstract

Density functional theory (DFT) calculations have been carried out to study the capacity of the B 1 2 N 1 2 nanocage encapsulated with alkali metals (Li, Na, K) for the CO2 adsorption and activation. It is found that after encapsulating alkali metals, the alkali metal atoms are closer to one side of clusters instead of exactly lying at the center, and a considerable charge transfers from the inner alkali metal atoms to the B 1 2 N 1 2 cage. Besides, the HOMO–LUMO gap (HLG) values of Li@B 1 2 N 1 2 , Na@B 1 2 N 1 2 and K@B 1 2 N 1 2 are decreased to about 6 eV, being much smaller than that of the pristine B 1 2 N 1 2 . Although the geometry structure parameters and the energy differences of M06-2X are slightly different from the ones of ω B97X-D, some identical results of two kinds of functional can be obtained. CO2 can be adsorbed chemically and physically on majority bonds of all the clusters, except for some bonds with large change in bond length and bond indices. The encapsulation of alkali-metal atoms may enhance the physical and chemical adsorption of CO2 on the surface of the clusters, in which Na@B 1 2 N 1 2 and K@B 1 2 N 1 2 are the most powerful physical and chemical adsorbent for CO2, respectively. Encapsulating alkali metal atoms in the B12N12 cluster would change the cage geometry and the electronic properties. In addition, it would significantly affect the energy changes in the physical and chemical adsorption processes of CO2 adsorbed on selected adsorption sites. The calculations are performed with the ωB97X-D and the M06-2X functional, and the results of two kinds of functional are identical. [ABSTRACT FROM AUTHOR]

Published
2019
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142. Recent trends of biodegradable mesoporous silica based nanoplatforms for enhanced tumor theranostics

Author

Ye, Mengwei, Xu, Qingqing, Jian, Huanhuan, Ding, Yiduo, Zhao, Wenpeng, Wang, Chenxiao, Lu, Junya, Feng, Shuaipeng, Wang, Siling, and Zhao, Qinfu

Abstract

Mesoporous silica nanoparticles (MSNs) are thought to be an attractive drug delivery material because of their advantages including high specific surface area, tunable pore size and morphology, easy surface modification and good biocompatibility. However, as a result of the poor biodegradability of MSNs, their biomedical applications are limited. To break the bottleneck of limited biomedical applications of MSNs, more and more researchers tend to design biodegradable MSNs (b-MSNs) nanosystems to obtain biodegradable as well as safe and reliable drug delivery carriers. In this review, we focused on summarizing strategies to improve the degradability of MSNs and innovatively proposed a series of advantages of b-MSNs, including controlled cargo release behavior, multifunctional frameworks, nano-catalysis, bio-imaging capabilities and enhanced therapeutic effects. Based on these advantages, we have innovatively summarized the applications of b-MSNs for enhanced tumor theranostics, including enhanced chemotherapy, delivery of nanosensitizers, gas molecules and biomacromolecules, initiation of immune response, synergistic therapies and image-guided tumor diagnostics. Finally, the challenges and further clinical translation potential of nanosystems based on b-MSNs are fully discussed and prospected. We believe that such b-MSNs delivery carriers will provide a timely reference for further applications in tumor theranostics.

Published
2024
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143. A Bioactive Nanocomposite Integrated Specific TAMs Target and Synergistic TAMs Repolarization for Effective Cancer Immunotherapy

Author

Gu, Wei, Guo, Wen, Ren, Zhishuang, Zhang, Yimeng, Han, Meiqi, Zhao, Qinfu, Gao, Yikun, Mao, Yuling, and Wang, Siling

Abstract

Reactive oxygen species (ROS) generated from photosensitizers exhibit great potential for repolarizing immunosuppressive tumor-associated macrophages (TAMs) toward the anti-tumor M1 phenotype, representing a promising cancer immunotherapy strategy. Nevertheless, their effectiveness in eliminating solid tumors is generally limited by the instability and inadequate TAMs-specific targeting of photosensitizers. Here, a novel core-shell integrated nano platform is proposed to achieve a coordinated strategy of repolarizing TAMs for potentiating cancer immunotherapy. Colloidal mesoporous silica nanoparticles (CMSN) are fabricated to encapsulate photosensitizer-Indocyanine Green (ICG) to improve their stability. Then GsE was coated on the surface of ICG/CMSN for targeting TAMs, as well as repolarizing TAMs concurrently, named ICG/CMSN@GsE. As expected, with the synergism of ICG and GsE, ICG/CMSN@GsE exhibited better stability, mild generation of ROS, favorable specificity toward M2-like macrophages, enhancing drug retention in tumors and superior TAMs repolarization potency, then exerted a potent antitumor effect. In vivo, experiment results also confirm the synergistic suppression of tumor growth accompanied by the increased presence of anti-tumor M1-like macrophages and maximal tumor damage. Taken together, by integrating the superiorities of TAMs targeting specificity and synergistic TAMs repolarization effect into a single nanoplatform, ICG/CMSN@GsE can readily serve as a safe and high-performance nanoplatform for enhanced cancer immunotherapy.

Published
2024
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144. Biodegradable copper-doped hollow mesoporous polydopamine nanoparticles for chemo/photothermal/chemodynamic synergistic therapy

Author

Xu, Qingqing, Li, Jiali, Liu, Bin, Chen, Guanghai, Qi, Wanhao, Lu, Junya, Wang, Siling, and Zhao, Qinfu

Abstract

Combination therapy has aroused widespread attention in overcoming the disadvantages of single therapies and improving treatment efficacy. Polydopamine (PDA), as a biodegradable organic photothermal material, has great potential for photothermal therapy (PTT) based combination therapy. In this work, a Cu2+-doped hollow mesoporous polydopamine (CHMP) was innovatively prepared for the first time with pH/H2O2/GSH/NIR light responsiveness for chemotherapy/PTT/chemodynamic therapy (CDT) combination therapy. By virtue of the incorporation of Cu2+, the degradability, GSH consumption ability and photothermal performance of hollow mesoporous polydopamine were significantly improved, endowing the CHMP with the ability to undergo Fenton-like reactions. Meanwhile, doxorubicin (DOX) was used as the model chemotherapeutic agent to be loaded into CHMP and grafted with PEG on the surface to construct a DOX/CHMPP nanoplatform. The photothermal conversion efficiency of CHMPP reached 40.64%, which could not only facilitate the thermal motion of drug molecules, enhance tumor cells uptake to drugs, but also promote the production of •OH. We evaluated the degradation behaviors of CHMPP and elucidated the feasible degradation process. Moreover, the cellular tests exhibited that DOX/CHMPP had remarkable synergistic therapeutic effects in tumor treatment involving chemo/PTT/CDT with a lower IC50of 0.73 μg/mL than that of DOX/CHMPP without NIR light irradiation (7.67 μg/mL). The in vivoanti-tumor effect suggested that the nanoplatform could accumulate in tumor sites to exert the ability of thermal imaging and have significantly synergistic therapeutic effect. Therefore, CHMPP could be used as a promising nanoplatform for PTT based combination therapy.

Published
2023
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145. Study on the rheoformability of semisolid 7075 wrought aluminum alloy using SEED process

Author

Zhao, Qinfu and Zhao, Qinfu

Abstract

Semisolid metal forming is becoming more and more attractive in the foundry industry due to its low cost and easy operation to produce high quality near-net-shape components. Over the past years, semisolid forming technique is mainly applied on the casting aluminum alloys due to their superior castability because of low melting temperature and viscosity. In semisolid forming field, thixoforming has been majorly used which involves of reheating the billet into semisolid state followed by casting process. Rheocasting is a more economic semisolid processing compared to thixoforming, which the semisolid billet is produced directly from liquid phase. The SEED process is one of reliable rheocasting techniques to produce high quality semisolid billets. To produce high quality semisolid billets, their unique rheological properties have been the most important issue need to be fully investigated. The aim of present project is to produce high quality semisolid AA7075 billets by SEED process and analyze their rheological properties under various process conditions. The effect of the SEED processing parameters and grain refiners on the semisolid microstructure and rheoformability were investigated. The deformation and rheological behavior of the semisolid billets of AA7075 base and its grain-refined alloys were studied using parallel-plate viscometer. In the first part, the evolution of liquid fraction to temperature of semisolid AA7075 alloy was investigated using Differential Scanning Calorimetry (DSC). It was found that the liquidus and solidus temperature of AA7075 alloy were 631℃ and 490℃ respectively. And the corresponding temperatures of solid fraction of 40% and 60% were 622℃ and 610℃, which was recognized as the temperature window for semisolid forming of this alloy. In the second part, the semisolid slurries were rheocasted using SEED technology and the effect of the SEED process parameters like swirling frequency and demolding temperature on evolution of microstructu

Published
2016

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