Copolymer F127 Research Articles

Electrochemical probing of encapsulation process for polymeric micelles

Many of the drugs used in pharmaceutical formulations are not photoactive. Cyclic voltammetry and differential pulse voltammetry can unveil hidden information about the binding mechanism between the host and guest. This work aims to demonstrate that electrochemical techniques can be used to monitor the binding mechanism. The electrochemical reversibility, stability, and the effect of time were investigated. Also, the kinetics parameter, binding constant, and apparent diffusion coefficient were estimated. The reversibility and stability increased when toluidine blue was in the surfactant medium. The effect of time showed that the toluidine blue did not permeate the copolymeric micelles. Although F-127 copolymer is more hydrophilic, the toluidine blue, bonded more effectively in P-123 (Kb = 3,846 L/mol) than in F-127 (Kb = 184 L/mol). The kinetics parameter corroborated with the Kb. The Dapp found in P-123 and F-127 micelles followed an unexpected trend, 3.7 and 4.8 μcm2 s−1, respectively.

Ultrasound-Induced Release Profile of Nimodipine from Drug-Loaded Block Copolymers after Singular vs. Repeated Sonication: In Vitro Analysis in Artificial Cerebrospinal Fluid.

Nimodipine still represents a unique selling point in the prevention of delayed cerebral ischemia (DCI) following aneurysmal subarachnoid hemorrhage (aSAH). Its intrathecal effect is limited by a low oral bioavailability, leading to the development of nanocarrier systems to overcome this limitation. This study investigated the ultrasound-induced release profile of nimodipine from drug-loaded copolymers in artificial cerebrospinal fluid (CSF) within 72 h after a singular versus repeated sonication. Pluronic® F127 copolymers (Sigma-Aldrich, Taufkirchen, Germany)were loaded with nimodipine by direct dissolution. Spontaneous and on-demand drug release by ultrasound (1 MHz at 1.7 W/cm2) was determined in artificial cerebrospinal fluid using the dialysis bag method. Nimodipine concentrations were measured at predefined time points within 72 h of sonication. Spontaneous release of nimodipine was enhanced by ultrasound application with significantly increased nimodipine concentrations two hours after a repeated sonication compared to a singular sonication (median 1.62 vs. 17.48 µg/µL, p = 0.04). A further trend was observed after four hours (median 1.82 vs. 22.09 µg/µL, p = 0.06). There was no difference in the overall nimodipine concentrations between the groups with a singular versus repeated sonication (357.2 vs. 540.3 µg/µL, p = 0.60) after 72 h. Repeated sonication resulted in an acceleration of nimodipine release from the drug-loaded copolymer in a CSF medium. These findings confirm the proof of principle of an on-demand guidance of nimodipine release from nimodipine-loaded nanodrugs by means of ultrasound, which suggests that evaluating the concept in an animal model may be appropriate.

Nanostructured systems based on pluronics to carry gold nanoparticles and methylene blue aiming for multimodal therapy

The rise of multidrug-resistant microorganisms has become a cause of concern in the biomedical field. In this sense, this study focuses on the development of an effective treatment for infectious diseases mediated by Multimodal Therapy, combining Photodynamic Therapy (PDT), and Photothermal Therapy (PTT). The system involves the synthesis and stabilization of gold nanoparticles (AuNPs) in Pluronic® micelles of F-127 and P-84, combined with the Methylene Blue (MB) aiming effects against microorganisms. It is noteworthy that the AuNPs were synthesized in situ in the copolymer using the solid dispersion technique. These copolymers were strategically chosen for evaluation purposes with our study involving P-123 previously published in this journal. Thus, the effect of the length of the PEO and PPO blocks can be delineated concerning the synthesis of AuNPs. In this case, copolymer F127 has PPO blocks identical to P-123 while P-84 has PEO blocks compatible with P-123. Characterization of the formulations included electronic absorption spectroscopy, dynamic light scattering, and transmission electron microscopy. Fluorescence quenching studies by Stern Volmer plots indicated the location of the MB in the hydrophilic corona of the micelles. In general, was verified that reducing the PEO/PPO ratio favors the formation of AuNPs, possibly due to the greater number of reducing sites per unit mass of the polymer. The formulations remained stable for at least 15 days, and photothermal studies showed a temperature increase of at least 11 °C. The photothermal effect proved reversible after three heating–cooling cycles, revealing a synergy between MB and AuNPs in heat generation, hindered by increased irradiance and rapid photobleaching of MB. The in vitro susceptibility tests with Candida albicans and Staphylococcus aureus demonstrated effective inhibition of the microorganisms. The result shows that AuNPs for itself do not affect the fungal/bacteria lineage. However, the MB/AuNPs combination samples, showed excellent fungal and bacterial inhibition at low drug concentrations.

Synthesis, characterization and in vitro release analysis of pluronic F127 copolymer micelles containing quercetin as a hydrophobic drug

Synthesis, characterization and in vitro release analysis of pluronic F127 copolymer micelles containing quercetin as a hydrophobic drug

Advanced theranostic nanoplatforms for hypericin delivery in the cancer treatment

Biomodified coated-lipid vesicles were obtained using the DPPC lipid (L) and F127 copolymer linked covalently with spermine (SN), biotin (BT), and folic acid (FA), resulting in LF127-SN, LF127-BT, and LF127-FA nanoplatforms. The photosensitizer hypericin (HY) was incorporated into the nanosystem by a thin-film method and characterized by dynamic light scattering, zeta potential, encapsulation efficiency, and transmission electronic microscopy. The results provided a good level of stability for all nanoplatforms for at least 5 days as an aqueous dispersion. The in vitro serum stability showed that the HY-loaded LF127-SN has a lower tendency to form complexes with BSA protein than with its analogs. LF127-SN was the most stable HY formulation, followed by LF127-BT and LF127-FA, confirmed by the association constant (Kd) values: 600 μmol L−1, 1100 μmol L−1, 515 μmol L−1, and 378 μmol L−1 for LF127, LF127 FA, LF127-BT, and LF127-SN, respectively. The photodynamic potential of HY was accessed by cytotoxicity assays using Caco-2, B16-F10, L-929, and HaCat cells. HY-loaded LF127-SN revealed a significant increase in the selectivity compared to other nanoplatforms. HY-loaded in LF127-BT and LF127-SN showed distinct uptake and biodistribution after 2 h of intravenous application. All biomodified coated-lipids showed satisfactory metabolism within 72 h after application, without significant accumulation or residue in any vital organ. These results suggest that incorporating HY-loaded in these nanosystems may be a promising strategy for future applications, even with a small amount of binders to the coating copolymer (0.02% w/v). Furthermore, these results indicate that the LF127-SN showed remarkable superiority compared to other evaluated systems, being the most distinct for future photodynamic therapy and theranostic applications.

Ultralow thermal conductivity of single-atom doped carbon aerogel synthesized with a facile ambient-pressure-drying strategy

Carbon aerogel is an attractive material for thermal insulation due to the porous character and high stability at high temperature. However, the wide application of carbon aerogel for thermal insulation is hindered by complicated supercritical-drying technology and high thermal conductivity of the pure carbon skeleton. Herein, a facile ambient-pressure-drying technology is developed for synthesizing Fe–N4 doped carbon aerogel through catalyzing the polymerization reaction of monomers under a Fe sol, with copolymer F127 as enhancement phase for wet-hydrogel. The whole process does not have any solvent exchange or aging procedure. The prepared carbon aerogel has an ultralow thermal conductivity of 0.048 W/(m ∙ K) at room temperature, with negligible 2% shrinkage during ambient-pressure-drying process and excellent mechanical behavior with stress of 0.58 MPa at 10% strain. The thermal conductivity of carbon-fiber reinforcement carbon aerogel is 0.158 W/(m ∙ K) at 1100 °C, and has an elasticity modulus of 108.3 MPa. Based on an ideal model, density functional theory calculations reveal that doping Fe–N4 can significantly enhance the anharmonicity of carbon-based materials and thus reduce the lattice thermal conductivity by more than 10 times. This work presents a facile and low-cost method for synthesizing carbon aerogel with single-atom doping for promising applications in thermal insulation.

Highly ordered mesostructured flexible silica-based nanofiltration membrane with satisfactory acid, chlorine, and fouling resistances

In this report, a highly ordered mesostructured flexible silica-based nanofiltration membrane is fabricated using tetraethyl orthosilicate (TEOS) as a silica source and Pluronic F127 copolymer as a structure directing agent, and hydrolyzed polyacrylonitrile ultrafiltration membrane as a substrate by an evaporation induced self-assembly approach. The results show the fabricated silica/F127 (SF) composite membrane possesses ordered mesostructures with different space groups depending on the mass ratios of TEOS/F127. The membrane is negatively charged with an isoelectric point at pH 2.9, and it also has a very hydrophilic surface. The pure water permeability of the membrane is 32 Lm−2h−1bar−1. The membrane also has high rejections to methyl blue (100%) and multivalent salts (> 95%), and moderate rejection to divalent salt (78.5% for Na2SO4). The ordering of the mesostructure enhances the membrane compactness, favoring the improvement of the separation performance. Additionally, the membrane possesses satisfactory resistances to humic acid (HA) and bull serum albumin (BSA) fouling, and bacteria adhesion due to the smooth and hydrophilic surface. Additionally, the salt rejection is stable in 0.5 M HCl for 11 h and/or active chlorine solution (pH = 5) with 9000 ppm·h chlorination strength accompanied by an obvious increase in permeate flux. The membrane also exhibits satisfactory performance stability in a long-term (168 h) running.

Facile Fabrication of Superwetting PVDF Membrane for Highly Efficient Oil/Water Separation.

A novel superhydrophilic and underwater superoleophobic modified PVDF membrane for oil/water separation was fabricated through a modified blending approach. Pluronic F127 and amphiphilic copolymer P (MMA-AA) were directly blended with PVDF as a hydrophilic polymeric additive to prepare membranes via phase inversion induced by immersion precipitation. Then, the as-prepared microfiltration membranes were annealed at 160 °C for a short time and quenched to room temperature. The resultant membranes exhibited contact angles of hexane larger than 150° no matter whether in an acidic or basic environment. For 1, 2-dichloroethane droplets, the membrane surface showed a change from superoleophilic to superoleophobic under water with aqueous solutions with pH values from 2 to 13. This as-prepared membrane has good mechanical strength and can then be applied for oil and water mixture separation.

Multifunctional Nanoparticles as High-Efficient Targeted Hypericin System for Theranostic Melanoma

Biotin, spermine, and folic acid were covalently linked to the F127 copolymer to obtain a new drug delivery system designed for HY-loaded PDT treatment against B16F10 cells. Chemical structures and binders quantification were performed by spectroscopy and spectrophotometric techniques (1NMR, HABA/Avidin reagent, fluorescamine assay). Critical micelle concentration, critical micelle temperature, size, polydispersity, and zeta potential indicate the hydrophobicity of the binders can influence the physicochemical parameters. Spermine-modified micelles showed fewer changes in their physical and chemical parameters than the F127 micelles without modification. Furthermore, zeta potential measurements suggest an increase in the physical stability of these carrier systems. The phototherapeutic potential was demonstrated using hypericin-loaded formulation against B16F10 cells, which shows that the combination of the binders on F127 copolymer micelles enhances the photosensitizer uptake and potentializes the photodynamic activity.

Photo-Phytotherapeutic Gel Composed of Copaifera reticulata, Chlorophylls, and k-Carrageenan: A New Perspective for Topical Healing.

Chronic wound healing represents an impactful financial burden on healthcare systems. In this context, the use of natural products as an alternative therapy reduces costs and maintains effectiveness. Phytotherapeutic gels applied in photodynamic therapy (PDT) have been developed to act as topical healing medicines and antibiotics. The bioactive system is composed of Spirulina sp. (source of chlorophylls) and Copaifera reticulata oil microdroplets, both incorporated into a polymeric blend constituted by kappa-carrageenan (k-car) and F127 copolymer, constituting a system in which all components are bioactive agents. The flow behavior and viscoelasticity of the formulations were investigated. The photodynamic activity was accessed from studies of the inactivation of Staphylococcus aureus bacteria, the main pathogen of hospital relevance. Furthermore, in vivo studies were conducted using eighteen rabbits with dermatitis (grade III and IV) in both paws. The gels showed significant antibiotic potential in vitro, eliminating up to 100% of S. aureus colonies in the presence or absence of light. The k-car reduced 41% of the viable cells; however, its benefits were enhanced by adding chlorophyll and copaiba oil. The animals treated with the phytotherapeutic medicine showed a reduction in lesion size, with healing and re-epithelialization verified in the histological analyses. The animals submitted to PDT displayed noticeable improvement, indicating this therapy's viability for ulcerative and infected wounds. This behavior was not observed in the iodine control treatment, which worsened the animals' condition. Therefore, gel formulations were a viable alternative for future pharmaceutical applications, aiming at topical healing.

Optimized metal-organic-framework based magnetic nanocomposites for efficient drug delivery and controlled release

Metal organic framework (MOF) has attracted wide attention as a promising biological platform due to its distinctive characteristics such as large surface areas, tunable pore sizes, and high selectivity in small molecule uptake. The incorporation of other guest materials into MOFs has resulted in additional functionalities of the conjugated MOF-composites. In this work, we have successfully conjugated Fe3O4 magnetic nanoparticles with MIL-88B–NH2 MOF structures using optimized synthetic media containing acetic acid as a modulating agent and F127 co-polymer as a stabilizing agent, which result in a well-controlled hybrid magnetic nanocomposite with an average size of 117 nm. This unique hybrid material has been further utilized as a nanocarrier for efficient drug delivery with the capability of on-demand controlled drug release. Glioblastoma drugs, including Carmustine (BCNU) and Mertansine (DM1), have been successfully loaded into the pores of the MOF structure to minimize their significant systemic toxic side effects that limit their clinical applications. Additionally, the controlled drug release was achieved through a localized heating effect produced by the magnetic nanodomains incorporated in the MOF structure after the application of an alternating magnetic field (AMF) on the DM1-loaded magnetic nanocomposites. In vitro cytotoxicity studies on U251 glioblastoma cells have been conducted to demonstrate the therapeutic efficacy of the drug delivery system and its capability of achieving on-demand drug release with the AMF as an external stimulus. Our results suggested that the fabricated magnetic nanocomposites are efficient for the controlled DM1 delivery, which exhibit superior cancer cell killing effects.

New trans-[Ru(NO)(NO2)(dppb)(o-bdqi)]+ complex as NO donor encapsulated Pluronic F-127 micelles

Ruthenium complexes that act as nitric oxide (NO) donors show potential cytotoxicity in tumor models. In this work, we proposed the synthesis of the new nitrosyl ruthenium complex trans-[Ru(NO2)(NO)(dppb)(o-bdqi)]Cl2, containing a non-innocent ligand of the o-phenylenediamine type (o-bdqi). The 31P{1H} NMR spectra confirmed that the trans-[Ru(NO2)(NO)(dppb)(o-bqdi)] is the isomer formed. The complex was characterized by elemental analysis, mass spectrometry, UV–vis and infrared spectroscopy and cyclic voltammetry. Natural transition orbitals (NTOs) for trans-[RuCl2(dppb)(o-bdqi)] and trans-[Ru(NO2)(NO)(dppb)(o-bdqi)]Cl2 complex were obtained with TD-DFT/B3LYP methodology to contribute to the assignment of electronic transition. A micellar system (F-127/Ru) produced with Pluronic F-127 copolymer was used as a drug delivery system, due to the hydrophobicity of the complex. The F-127/Ru system showed NO release in aqueous media. The free complex showed higher cytotoxicity than the F-127/Ru system in the studied tumor cells. However, the F-127/Ru system showed a higher selectivity index for lung cells. This shows that the Pluronic F-127 carrier can be a good alternative in the use of hydrophobic nitrosyl ruthenium compounds in the treatment of some types of cancer.

Kinetics-controlled regulation for homogeneous nucleation and growth of colloidal polymer and carbon nanospheres.

Size regulation of uniform polymer nanospheres (PNSs) and carbon nanospheres (CNSs) below 100 nm has been difficult and is limited by multiple factors, such as ongoing nucleation, Ostwald ripening, minimization of surface energy, and high viscosity during the nucleation and growth process. In this study, a kinetics-controlled regulation is reported for the synthesis of monodispersed PNSs and corresponding CNSs with adjustable size below 100 nm. During the synthesis of PNSs, three distinct stages including surface energy control, surface tension control and viscosity control have been observed, where the concentration of block copolymer F127 (CF127) plays a vital role in affecting the nucleation rate of PNSs and tunes the diffusion rate of monomers and migration of particles during the nucleation and growth process. As a consequence, the size of monodisperse CNSs can be customized from 100 nm down to 41 nm with PDI below 5%.

Brefeldin A delivery nanomicelles in hepatocellular carcinoma therapy: Characterization, cytotoxic evaluation in vitro, and antitumor efficiency in vivo

Hepatocellular carcinoma (HCC) is one of the major cancers with high mortality rate. Traditional drugs used in clinic are usually limited by the drug resistance and side effect and novel agents are still needed. Macrolide brefeldin A (BFA) is a well-known lead compound in cancer chemotherapy, however, with poor solubility and instability. In this study, to overcome these disadvantages, BFA was encapsulated in mixed nanomicelles based on TPGS and F127 copolymers (M-BFA). M-BFA was conferred high solubility, colloidal stability, and capability of sustained release of intact BFA. In vitro, M-BFA markedly inhibited the proliferation, induced G0/G1 phase arrest, and caspase-dependent apoptosis in human liver carcinoma HepG2 cells. Moreover, M-BFA also induced autophagic cell death via Akt/mTOR and ERK pathways. In HepG2 tumor-bearing xenograft mice, indocyanine green (ICG) as a fluorescent probe loaded in M-BFA distributed to the tumor tissue rapidly, prolonged the blood circulation, and improved the tumor accumulation capacity. More importantly, M-BFA (10 mg/kg) dramatically delayed the tumor progression and induced extensive necrosis of the tumor tissues. Taken together, the present work suggests that M-BFA has promising potential in HCC therapy.

0D/3D coupling of g-C3N4 QDs/hierarchical macro-mesoporous CuO-SiO2 for high-efficiency norfloxacin removal in photo-Fenton-like processes

Photo-Fenton process is an advanced oxidation technology, which is used to eliminate organic pollutants in environmental pollution. In this paper, g-C3N4 quantum dots incorporated hierarchical macro-mesoporous CuO-SiO2 (MM SC-QDs) composite was successfully fabricated by a dual-template method combined with polystyrene sphere (PS) crystal and copolymer F127. With the presence of H2O2, MM SC-QDs exhibited excellent degradation performance against the antibiotic pollutant norfloxacin (NOR) under visible-light assisted heterogeneous Fenton process at neutral condition, which was 27 times higher than that of the Bulk CuO-SiO2. Interconnected macropores, together with abundant mesopores effectively expand specific surface area and improve mass transfer. In addition, the g-C3N4 QDs served as the separation center for photogenerated charges, promoting the separation and migration of the charge carriers. Wherein, the long-lived photogenerated electrons were effectively separated and transferred to the surface of CuO-SiO2, which accelerated the reduction rate of Cu2+ to Cu+, enhancing the photo-Fenton-like catalytic activity. This stable, efficient, and environmentally friendly Cu-based heterogeneous photo-Fenton-like catalyst is expected to become an effective implementation in organic pollution removal. Meanwhile, this paper proves that Cu-based materials can activate H2O2 to generate singlet oxygen (1O2) for the degradation of organic pollutants. The transformation mechanism of 1O2 was clarified, which is helpful to better understand the Fenton-like reaction process of Cu-based materials.

Theranostic Near-Infrared-Active Conjugated Polymer Nanoparticles

Conjugated polymer nanoparticles (CPNs) based on a common solar cell material (PTB7) have been prepared, and their potential in theranostic applications based on bioimaging and photosensitizing capabilities has been evaluated. The main absorption and emission bands of the prepared CPNs both fell within the NIR-I (650-950 nm) transparency window, allowing facile and efficient implementation of our CPNs as bioimaging agents, as demonstrated in this work for A549 human lung cancer cell cultures. The prepared CPN samples were also shown to produce reactive oxygen species (ROS) upon photoexcitation in the near-infrared or ultraviolet spectral regions, both in aqueous solutions and in HaCaT keratinocyte cell cultures. Importantly, we show that the photosensitizing ability of our CPNs was largely determined by the nature of the stabilizing shell: coating the CPNs with a Pluronic F-127 copolymer led to an improvement of photoinitiated ROS production, while using poly[styrene-co-maleic anhydride] instead completely quenched said process. This work therefore demonstrates that the photosensitizing capability of CPNs can be modulated via an appropriate selection of stabilizing material and highlights the significance of this parameter for the on-demand design of theranostic probes based on CPNs.

Photophysical characterization of Hypericin-loaded in micellar, liposomal and copolymer-lipid nanostructures based F127 and DPPC liposomes

Hypericin (Hy) compound presents a high photoactivity in photodynamic therapy (PDT), photodiagnosis and theranostics applications. The maintenance of this compound in monomeric form could undermine the potential benefits of its photophysical and photodynamic activity. In this study, we demonstrated that the Hy formulated in a system based on the use of the F127 copolymer and the 1,2-dipalmitoyl-sn-3-glycerol-phosphatidylcholine (DPPC) as micelles, liposomal vesicles and Copolymer-Lipid coated systems, have improved its photophysical properties for many clinical modalities. Based on the results of the triplet state lifetime values (τt), the singlet oxygen quantum yield (ΦΔ1O2), the fluorescence lifetime (τF) and the fluorescence quantum yield (ΦF), all Hy formulations had its photophysical properties described in different models of drug delivery systems (DDS). In addition, the transient spectra profile of those formulations was unaffected by the Hy incorporation process, except for the liposomal system, which demonstrated to be the less stable one by flash photolysis technique. The cytotoxic effects of those formulations were also investigated for CaCo-2 and HaCat cells line. The cytotoxic concentrations for 50% (CC50) were 0.56, 1.05, 1.33 and 4.80 µmol L-1 for Copolymer-Lipid/Hy, DPPC/Hy, F127/Hy and ethanol/Hy for CaCo-2 cells, respectively, and 0.69, 2.02, 1.45 and 1.16 µmol L-1 for Copolymer-Lipid/Hy, DPPC/Hy, F127/Hy and ethanol/Hy for HaCat cells, respectively. The F127 copolymer had a significant role in many photophysical parameters determined for Copolymer-Lipid/Hy coated system. Although all those formulations had shown satisfactory results, Copolymer-Lipid/Hy proved to be superior in many aspects, being the most promising formulation for PDT, photodiagnosis and theranostics applications.

Folate-targeted nanomicelles containing silibinin as an active drug delivery system for liver cancer therapy

The majority of herbal anticancer drugs are insoluble in water or become unstable during their transport to tumor tissues, hence they require a special drug delivery system. The main target of this study was to evaluate the therapeutic efficacy of silibinin (SLB)-loaded folic acid (FA)-conjugated Pluronic F127 (SLB-F127-FA) nanomicelles as an active-targeted drug delivery platform for liver cancer treatment. To prepare SLB-F127-FA nanomicelles, folic acid was first conjugated to hydrophilic chains of Pluronic F127 copolymer by the Steglich esterification technique. Then, silibinin was encapsulated in the self-assembled hydrophobic core of FA-conjugated F127 to render SLB-F127-FA nanomicelles. The prepared nano micelles had an almost spherical shape with an average particle size of 17.7 nm. The average hydrodynamic size of non-targeted (SLB-F127) and targeted (SLB-F127-FA) nanomicelles, measured by dynamic light scattering analysis (DLS), was 19.6 and 29.2 nm, respectively. Also, the drug loading content as well as entrapment efficiency of SLB-F127-FA nanomicelles were obtained to be 2.36% and 79.43%, respectively. The in vitro release patterns of SLB from nanomicelles showed a slow and sustained release behavior in comparison to free SLB. Moreover, it was observed that the kinetic release of silibinin from the SLB-F127-FA nanomicelles at 37 °C conforms well to Korsmeyer-Peppas kinetic model (R2 = 0.99, n = 0.22), suggesting a dominate release mechanism of the Fickian diffusion type. Moreover, in vitro cytotoxic study indicated that the viability of human liver cancer cells (HepG2) exposed to SLB-PF127-FA nanomicelles was significantly lower than that of treated with non-targeted nanomicelles (SLB-F127) or free SLB. Our results suggest that SLB-F127-FA nanomicelles can be considered as a promising targeted drug delivery platform for liver cancer therapy and/or delivering other hydrophobic drugs to different types of cancers with folate-receptor overexpression.

Synthesis and characterization of 5(6)-carboxyfluorescein-conjugated F127 and 10R5 copolymers as potential water-soluble fluorescence probes

Abstract In this work, a chemical data collections is regarding the synthesis, purification and characterization of water-soluble fluorescent probes based on (5)6-carboxyfluorescein (CF)-conjugated with normal and reverse triblock copolymers (F127 and 10R5). Due to the fact that F127 shows low solubility in organic solvents, most studies involve the removal of dicyclohexylurea (side product) using ether solution, resulting in an unclean material for to medicinal applications. In our study, cleaner purification protocols were performed by using dialysis and size-exclusion column chromatography (SEC) in a water medium for obtaining F127-CF and 10R5-CF copolymers with in good yields (80–85%). Proton nuclear magnetic resonance (1H NMR) was employed to confirm the chemical structures of the final products.

Morphological and electrical study of porous TiO2 films with various concentrations of Pluronic F-127 additive

Porous TiO2 thin films were synthesized by dip-coating method on silicon substrates. Pluronic F-127 (F127), a structure-directing agent, was used to promote the evolution of pores during the synthesis of TiO2 thin films. The concentration of F127 was varied from 0.3 to 3.75 mM. FESEM micrograph has confirmed the presence of porous morphology, whereas XRD and Raman studies have revealed the formation of the anatase phase of the sample. Capacitance–voltage (C–V) measurement was carried out using TiO2 based metal oxide semiconductor (MOS) capacitor structure, where F127 was incorporated in the oxide layer. The oxide charge density was found to be increased with the concentration of F127 co-polymer. Interface trap density has a maximum value of 6.6 × 1012 eV−1 cm−2 after the addition of 3 mM of F127. It was found out that the 3 mM of F127 has better memory effect during the resistive switching study.