This study investigates the photophysical and electrical properties of 4-heptamethyl-trisiloxanyl-n-undecyloxy-4 ' nitrostilbene (SNS), a low molar mass organosiloxane liquid crystal containing a nitrostilbene chromophore. Real-time monitoring of the absorption and fluorescence spectra of the nitrostilbene moiety was conducted in dichloromethane solution and thin films (in both crystalline and Smectic C (SmC) phases). A charge transfer excited state is formed following vibrational cooling and solvent interaction within 0.4 to 1.6 ps, which then relaxes to the ground state in 1.6 ns. Five distinct lifetime components were identified in thin films, attributed to the heterogeneous local environment and aggregate formation. Notable differences in excited-state lifetimes were observed between the crystalline and SmC phases, with slower dynamics in the former due to the rigidity of the crystalline phase. Photoconductivity under UV irradiation was examined in SmC, Smectic A (SmA), and isotropic phases, showing a significant increase in current response, particularly in the SmC phase. Polarizing optical microscopy revealed morphological changes post-UV exposure, such as reduced SmC domain size and decreased birefringence. Dielectric measurements indicated distinct relaxation peaks in SmC and SmA phases, reflecting more disordered molecular arrangements. The study reveals that UV exposure significantly enhances SNS conductivity, particularly within the SmC phase. This enhancement is likely attributed to UV excitation promoting the formation of an intramolecular charge transfer state within the trans-stilbene moiety. These findings provide valuable insights into the potential applications of nitrostilbene-functionalized organosiloxane liquid crystals in optoelectronic devices, such as light switches and photodetectors.

The distinctive characteristics of near-infrared fluorescent organic molecules render them indispensable across diverse applications, from energy harvesting to bioimaging and sensing technologies. In this work, we continue our investigation on the chalcone derivative, 4-dimethylamino-2 '-hydroxychalcone (nDHC, n = 1; where n is the number of olefinic bonds), by expanding the number of central double bonds (n = 2 (2DHC) and n = 3 (3DHC)). Additionally, we also synthesized the structurally related chalcones lacking the OH group (DC, 2DC, 3DC) in order to obtain a comprehensive understanding of their effects on the intramolecular charge transfer (ICT). The results show remarkable bathochromic shifts in absorption and fluorescence peaks in solution as n increases. These shifts, 20 nm and 35 nm for absorption and 100 nm and 200 nm for fluorescence in 2DHC and 3DHC, respectively, signify enhanced ICT and a significant increase in the excited state's dipole moment. The presence of OH groups notably amplifies these shifts due to additional electron donation, influencing solute-solvent interactions in solution. Femtosecond fluorescence upconversion and transient absoprtion techniques unraveled distinct dynamics in these derivatives, exhibiting the dominance of vibrational cooling, solvation, and intramolecular motions, particularly in the larger conjugated systems 3DHC and 3DC. The observed changes in the femtosecond transinet absorption spectra suggest the existence of new active states in extended conjugation systems, indicating diverse intramolecular conformational states contributing to their relaxation dynamics. The results of this study provide invaluable insights into excited-state spectroscopy, offering a roadmap for tailoring chalcone derivatives for specific applications. Expanding the conjugation center between the donor and acceptor in chalcone molecules enhances induced intramolecular charge transfer, accompanied by ultrafast twisting, causing the fluorescence to shift from green to near-infrared in polar solvents.

Efficient electron injection from photosensitizers to semiconductor nanoparticles is essential in many ap-plications such as solar energy harvesting and catalytic reactions. Herein, we present a promising pho-tosensitizer, 4-dimethylamino-2'-hydroxy-4'-carboxychalcone (DHC-COOH), that upon adsorption on TiO2 nanoparticles shows enhanced electron transfer from its excited state to the conduction band (CB) of TiO2 via an intramolecular charge transfer (ICT). In order to fully characterize the current system, three more derivatives were synthesized and characterized, its analogue without the COOH group (DHC), and the molecules without the OH group (DC and DC-COOH). The presence of OH causes a red shift in the absorption and fluorescence spectra, whereas the COOH group induces more red shift due to efficient ICT which is also seen in the density functional theory calculations. Excited-state intramolecular proton trans-fer is evident in the crystalline/solid form of DHC and DHC-COOH as a large red shift in the fluorescence peak. The red shift was not observed when DHC-COOH was adsorbed on the TiO2 surface due to the in-volvement of the OH group in binding. This was confirmed by XPS, in addition to a bidentate binding of the COOH group to TiO2. The latter has a major contribution to the electron transfer mechanism which was observed as a much weaker fluorescence intensity and a 50% reduction in the lifetime component that involves the COOH dynamic (from 63 ps to 32 ps). On the other hand, electron-hole recombination dynamics were slowed down on the TiO2 surface (from 311 ps to 440 ps and 1.4 ns to 2.4 ns). From cyclic voltammetry and steady state spectra, it was found that electron injection from the excited state of the dye to the CB of TiO2 is energetically favorable, and regeneration of the oxidized dye by the I -/I3 - redox pair (used in dye-sensitized solar cells) is also possible.(c) 2022 Elsevier B.V. All rights reserved.

We investigated the effect of different electron-donating groups on the intramolecular charge transfer (ICT) process in three hydroxychalcone derivatives. More efficient ICT was observed when replacing N(Me)2 by pyrrolidine due to less hydrogen bonding with solvent. Adding NH2 to the structure caused more planarity that was detected as a larger fluorescence quantum yield and narrower fluorescence peak. This was confirmed by femtosecond transient absorption in which the intramolecular twisting process, observed in the other derivatives, was absent in the presence of NH2. This work should be a useful step toward understanding and tailoring the excited state spectroscopy of chalcone derivatives.

We investigate the role of quantum confinement and photoluminescence (PL) lifetime of photoexcited charge carriers in semiconductor core/shell quantum dots (QDs) via PL quenching due to surface modification. Surface modification is controlled by varying the number of dye molecules adsorbed onto the QD shell surface forming QD-dye nanoassemblies. We selected CuInS2/ZnS (CIS) and InP/ZnS (InP) core/shell QDs exhibiting relatively weak (664 meV) and strong (1194 meV) confinement potentials for the conduction band electron. Moreover, the difference in the emission mechanism gives rise to a long and short excited state lifetime of CIS (ca. 290 ns) and InP (ca. 37 ns) QDs. Dye molecules of different ionic characters (rhodamine 575: zwitterionic and rhodamine 560: cationic) are used as quenchers. A detailed analysis of Stern-Volmer data shows that (i) quenching is generally more pronounced in CIS-dye assemblies as compared to InP-dye assemblies, (ii) dynamic quenching is dominating in all QD-dye assemblies with only a minor contribution from static quenching and (iii) the cationic dye shows a stronger interaction with the QD shell surface than the zwitterionic dye. Observations (i) and (ii) can be explained by the differences in the amplitude of the electronic component of the exciton wavefunction near the dye binding sites in both QDs, which results in the breaking up of the electron-hole pair and favors charge trapping. Observation (iii) can be attributed to the variations in electrostatic interactions between the negatively charged QD shell surface and the cationic and zwitterionic dyes, with the former exhibiting a stronger interaction. Moreover, the long lifetime of CIS QDs facilitates us to easily probe different time scales of the trapping processes and thus differentiate the origins of static and dynamic quenching components that appear in the Stern-Volmer analysis.

We have prepared and characterised a series of side-chain liquid crystalline homopolymers and terpolymers containing different azobenzene derivatives (RAzB), sulfonic groups (2-acrylamido-2-methyl-1-propanesulfonic acid, AMPS), and methyl(methacrylate) groups (MMA), as monomeric units. We have evaluated the effect of different para-substitutes of 6-(4-azobenzene -4'-oxy)hexyl methacrylate, at the side chains, OCH3, NO2 and H, on the phase behaviour and conductivity of the new polymers. The copolymers can form smectic and nematic phases, depending on their composition, and have light responsiveness, conferred by the azobenzene chromophores. The terpolymer with methoxy terminations, MeOAzB/AMPS/MMA, exhibits the highest conductivity values of the series (10(-2)/10(-3) S.cm(-1) range) through liquid crystalline phases and with signs of decoupling from polymeric segmental motions. These materials are promising candidates to develop new light-responsive polymeric electrolytes for electrochemical conversion devices in which ionic conductivity under anhydrous conditions can be controlled by their nanostructure.

Light-responsive materials capable of undergoing photoinduced molecular transformation are excellent candidates for energy storage. Herein, we report a promising new liquid crystalline terpolymer that is capable of trapping the absorbed photon energy upon exposure to UV light through trans -> cis isomerization and molecular aggregation. MeOAzB-T (contains pmethoxyazobenzene, 2- acrylamido- 2-methyl-1-propanesulfonic acid, and methyl(methacrylate) monomeric units) shows a trans. cis normal thermal recovery in solution (THF) after UV exposure, whereas in the glassy state (at 22 degrees C) and smectic phase (at 75 degrees C), the recovery process indicates an unusual increase in absorbance of the trans isomer. Surprisingly, when the smectic phase was cooled down to the glassy state while maintaining UV exposure, the increase in absorbance of the trans isomer was maintained at the same level in the dark (monitored for 20 days) until the sample was heated to 75 degrees C and then cooled to 22 degrees C in which a full recovery was achieved. Enhancement of H- and Jaggregations of the trans-MeOAzB units was found to be responsible for the absorbance increase. Both forms of aggregation have absorbance signatures and were reproduced by time-dependent density functional theory (TD-DFT). A long lifetime component was detected in the femtosecond transient absorption (TA) spectra in thin films (215 ps in the glass state and 97 ps in the smectic phase) and was assigned to a long-lived intermediate state as a result of aggregation. The stability of the excited state leads to more aggregation as a consequence of the larger dipole moment, compared to the ground state, which is manifested in the TD-DFT calculations as an increase in electron density at the central azo bond. The current results suggest that aggregation after UV irradiation can be maintained for a long time at room temperature and can be relaxed to the original configuration by heating above the glass transition, showing the suitability of MeOAzB-T as a solar thermal fuel.

Photoluminescence (PL) quenching of nanoassemblies of CuInS2/ZnS quantum dots (CIS QDs) and rhodamine 560 molecules (Rh560) is spectroscopically investigated by steady-state and femtosecond-to-nanosecond time-resolved techniques. Fluorescence lifetime measurements of CIS QDs show a bi-exponential decay (time constants ca. 650 ns and 210 ns) that are assigned to the radiative recombination of delocalized CB electrons with localized holes, presumably associated with Cu-related defect sites. A trapped electron recombines non-radiatively with the localized hole. That means, electron trapping is the first step in the nonradiative recombination pathway in CIS QDs. The traps are of surface origin and are likely associated with unpassivated dangling bonds. In this work, we controlled the trap density by varying the amount of Rh560 on the QD surface and monitoring the electron trapping in different time scales. Transient absorption measurements of the CIS-Rh560 assemblies resolved the fast component of electron trapping that occurs in tens to hundreds of picoseconds, while fluorescence lifetime measurements resolved the slow components of trapping that occur in hundreds of nanoseconds. Unlike the case of more traditional CdSe/ZnS QDs, the PL lifetime of CIS QDs approaches the typical time scale of fluorescence intermittency. As a result, the excited state of CIS QDs is vulnerable to the blinking process. In the CIS-Rh560 assembly, trapping of CB electrons increases with dye loading which eventually prolongs the dark (or dim) period and therefore reduces the fluorescence quantum yield of CIS QDs. The appearance of short lifetime components (ca. 0.5-6.9 ns) in the QD-dye assembly hints that Auger quenching process and/or electron-phonon coupling seems to play a major role in the PL quenching process.

Corrosion of metals is an important economic problem globally. The use of corrosion inhibitors, mainly those based on surfactants, is one of the most efficient ways of defending metal surfaces against corrosion. This study aimed to synthesis some novel ethoxylated and sulfonated fatty alcohol surfactants. The symbols B1, B2, and B3 were pointed to R–CH2O–(CH2CH2O)20–SO3Na, R–CH2O–(CH2CH2O)20–H, and R–CH2O–(CH2CH2O)7–SO3Na, respectively. Spectroscopic methods (FTIR, 1H NMR) were used to characterize the compounds. Micelle concentration (CMC) for the synthesized surfactants was determined and discussed. The surface tension and thermodynamic properties of these inhibitors were investigated. The ability of the synthesized ethoxylated and sulfonated compounds to inhibit the corrosion of C-steel was investigated. Electrochemical, and surface analysis techniques were used to describe the corrosion behavior in blank and inhibiting solutions. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), and electrochemical frequency modulation (EFM) were used as electrochemical techniques at 25 °C. The inhibition efficiency increases with the concentration. A higher inhibition efficiency among the investigated compounds was at the concentration of 300 ppm from compound B1. The investigated surfactants behave as mixed corrosion inhibitors. It was found that the adsorption process obeys Langmuir isotherm. Adsorption parameters were calculated then explained. The adsorption of the investigated compounds is physisorption. The surface morphology of the C-steel and the formed protective film were examined using SEM. The order of inhibition efficiencies was B1 > B2 > B3. The data obtained from various techniques were in good agreement.

In an effort to enhance the absorption and fluorescence of flavylium in the red and near-infrared (NIR) spectral region, we synthesized a 2′-hydroxyflavylium derivative (FLV-OH) with a rigid electron donating julolidine group attached to position 7 and examined its ground and excited states spectroscopy by absorption, fluorescence, ultrafast dynamics, and by density functional theory (DFT). The precursor compound without the hydroxyl group (FLV) was also synthesized and characterized in order to clarify the role of the intramolecular hydrogen bond on the spectroscopy of FLV-OH. The S1 ← S0 absorption peaks at 540 nm and extends to 620 nm, whereas the corresponding fluorescence has two peaks and extends to 900 nm. The ability of the flavylium moiety to undergo ring opening to form chalcone is observed in basic solution. The presence of the hydroxyl group in FLV-OH promotes the formation of a quinonoidal base which was not possible in FLV. Femtosecond fluorescence upconversion and transient absorption measurements reveal the solvation dynamics within the initial 1-2 ps after photexcitation, followed by molecular relaxation to the ground state. The latter was measured to be 505 ps in FLV-OH and 164 ps in FLV. The longer lifetime of FLV-OH in the excited state is correlated to the presence of a hydrogen bond (OH---O) that tends to stabilize the excited molecule. The current results indicate that FLV-OH has spectroscopic properties that make it suitable for many applications such as a potential light harvesting dye in solar cell

Accurate intraoperative tumour margin assessment is a major challenge in neurooncology, where sparse tumours beyond the bulk tumour are left undetected under conventional resection. Non-linear optical imaging can diagnose tissue at the sub-micron level and provide functional label-free histopathology in vivo . For this reason, a non-linear endomicroscope is being developed to characterize brain tissue intraoperatively based on multiple endogenous optical contrasts such as spectrally- and temporally-resolved fluorescence. To produce highly sensitive optical signatures that are specific to a given tissue type, short femtosecond pulsed lasers are required for efficient two-photon excitation. Yet, the potential of causing bio-damage has not been studied on neuronal tissue. Therefore, as a prerequisite to clinically testing the non-linear endomicroscope in vivo , the effect of short laser pulse durations (40–340 fs) on ex vivo brain tissue was investigated by monitoring the intensity, the spectral, and the lifetime properties of endogenous fluorophores under 800 and 890 nm two-photon excitation using a bi-modal non-linear endoscope. These properties were also validated by imaging samples on a benchtop multiphoton microscope. Our results show that under a constant mean laser power, excitation pulses as short as 40 fs do not negatively alter the biochemical/ biophysical properties of tissue even for prolonged irradiation.

Eliminating time-consuming process of conventional biopsy is a practical improvement, as well as increasing the accuracy of tissue diagnoses and patient comfort. We addressed these needs by developing a multimodal nonlinear endomicroscope that allows real-time optical biopsies during surgical procedure. It will provide immediate information for diagnostic use without removal of tissue and will assist the choice of the optimal surgical strategy. This instrument will combine several means of contrast: non-linear fluorescence, second harmonic generation signal, reflectance, fluorescence lifetime and spectral analysis. Multimodality is crucial for reliable and comprehensive analysis of tissue. Parallel to the instrumental development, we currently improve our understanding of the endogeneous fluorescence signal with the different modalities that will be implemented in the stated. This endeavor will allow to create a database on the optical signature of the diseased and control brain tissues. This proceeding will present the preliminary results of this database on three types of tissues: cortex, metastasis and glioblastoma.

Meningioma is the most frequent primary central nervous system tumor. The risk of recurrence and the prognosis are correlated with the extent of the resection that ideally encompasses the infiltrated dura mater and, if required, the infiltrated bone. No device can deliver real-time intraoperative histopathological information on the tumor environment to help the neurosurgeon to achieve a gross total removal. This study assessed the abilities of nonlinear microscopy to provide relevant and real-time data to help resection of meningiomas. Nine human meningioma samples (four World Health Organization Grade I, five Grade II) were analyzed using different optical modalities: spectral analysis and imaging, lifetime measurements, fluorescence lifetime imaging microscopy, fluorescence emitted under one- and two-photon excitation and the second-harmonic generation signal imaging using a multimodal setup. Nonlinear microscopy produced images close to histopathology as a gold standard. The second-harmonic generation signal delineated the collagen background and two-photon fluorescence underlined cell cytoplasm. The matching between fluorescence images and Hematoxylin and Eosin staining was possible in all cases. Grade I meningioma emitted less autofluorescence than Grade II meningioma and Grade II meningioma exhibited a distinct lifetime value. Autofluorescence was correlated with the proliferation rates and seemed to explain the observed differences between Grade I and II meningiomas. This preliminary multimodal study focused on human meningioma samples confirms the potential of tissue autofluorescence analysis and nonlinear microscopy in helping intraoperatively neurosurgeons to reach the actual boundaries of the tumor infiltration. Correspondence between H&E staining (top pictures) and the two-photon fluorescence imaging (bottom pictures).

Delineating tumor margins as accurately as possible is of primordial importance in surgical oncology: extent of resection is associated with survival but respect of healthy surrounding tissue is necessary for preserved quality of life. The real-time analysis of the endogeneous fluorescence signal of brain tissues is a promising tool for defining margins of brain tumors. The present study aims to demonstrate the feasibility of multimodal optical analysis to discriminate fresh samples of gliomas, metastases and meningiomas from their appropriate controls. Tumor samples were studied on an optical fibered endoscope using spectral and fluorescence lifetime analysis and then on a multimodal set-up for acquiring spectral, one and two-photon fluorescence images, second harmonic generation signals and two-photon fluorescence lifetime datasets. The obtained data allowed us to differentiate healthy samples from tumor samples. These results confirmed the possible clinical relevance of this real-time multimodal optical analysis. This technique can be easily applied to neurosurgical procedures for a better delineation of surgical margins.

The effect of Psidium guajava leaf as corrosion inhibitors in 10 % sulfamic acid solution was conducted using different techniques at temperatures 298 K.The effect of temperature was studied and activation and adsorption thermodynamic parameters were computed and discussed. The surface morphology was analyzed using scanning electron microscope (SEM). Potentiodynamic polarization studies showed that Psidium guajava leaf acts as mixed type inhibitor for corrosion of C-steel in 10% NH2SO3H solution. The addition of Psidium guajava leaf led to increase in the charge transfer resistance (Rct) and decrease in capacitance of the double layer (Cdl). The inhibition mechanism involve physisorption. The adsorption of this extract on C-steel surface obeys isotherm. All studied techniques gave similar results. Surface of C-steel was analyzed using scanning electron microscopy (SEM) technique. © 2016 Elixir all rights reserved. Elixir Corrosion & Dye 91 (2016) 38510-38518 Corrosion and Dye Available online at www.elixirpublishers.com (Elixir International Journal) A. S. Fouda et al./ Elixir Corrosion & Dye 91 (2016) 38510-38518 38511 Gravimetric Technique Weight loss measurements of six similar prepared C-steel coupons with dimension (2.0x2.0x0.2)cm. which abraded with various grade emery papers up to 2000, then washed with bidistilled water and acetone, then weighed. The coupons were suspended in 100 ml of 10% NH2SO3H with and without addition of different concentrations of Psidium guajava leaf extract. Through period time 30 min. takeout coupons, washed, dried and re-weighted accurately through 3hr. at various temperatures from 298 to 328 K [14, 15]. The mean weight losses were obtained. The surface coverage θ and inhibition efficiency IE%. Can be obtained from equation (1): IE%= θ x 100 = [1-(W / Wo)]x 100 (1) Where, W and Wo are the mean weight losses with and without addition of Psidium guajava respectively. Corrosion rate was calculated using equation (2): Corrosion Rate k = W/ A xt (2) Where, W is weight loss at certain time (t) in min and (A) area in cm 2 . [16] Electrochemical Techniques Electrochemical experiments were carried out using cell consists of three electrodes (a) Working electrode is 1cm 2 Csteel welded with Cu-wire for electrical connection and mounted into glass tube of appropriate diameter and use epoxy resin to make the contact area of the electrode to be 1 cm 2 . This electrode is abradedas before. [24](b) Reference electrode is saturated calomel electrode SCE. Used directly in contact with working solution, while all potential value were recordedvs. SCE. Lugging-Haber capillary tube was also include in the design, Lugging capillary tip is made very close to the surface of the working electrode minimize IR drop. [17](c) Platinum foil (1cm 2 ) as auxiliary electrode. All electrochemical measurements were performed in solution 10% NH2SO3H in presence and absence various concentrations of the extract at 298 K under un-stirred and aerated conditions. The measurements were performed using Gamry instrument Potentiostat / Galvanostat, ZRA(PCI4G750), this include Gamry applications include DC105 software for DC corrosion, EIS300 software for electrochemical impedance spectroscopy, and EFM140 for electrochemical frequency modulation measurements along with computer for collecting data and analysis it by use Echem analyst V.6.03 used for plotting, graphing, and fitting the result data. Open circuit potential (OCP) The first step in electrochemical experiment. Working electrode was measure as function oftime during 1hr. this time necessary to reach steady stateand obtain (OCP) value. Non-destructive method (a) EIS measurements were carried outin frequency range from 0.3 Hz to 100 KHz with amplitude of 5 mV peak to peak using Ac signals at open circle potential. The experimental impedance was analyzed and interpreted based on the equivalent circuit. The main parameter deduced from EIS analysis are Rct charge transfer resistance, capacitance of double layer,Cdl. Inhibition efficiency (IE %)and surface coverage (Ɵ) were defined by this equation (3). IE % = θ x 100 = [1-(R°ct / Rct)] x 100 (3) Where R°ct, Rct are the charge transfer resistance in the absence and presence of extract, respectively[18]. (b) EFM measurements were carried out using two frequency 2 and 5 Hz. The base frequency was 0.1 Hz, so the wave form repeat after 1 sec. the higher frequency must me at least two time the lower one. The higher frequency must also be sufficiently slow that the charging of double layer dose not contribute to the current response. Often 10 Hz reasonable limit. The intermodulation spectra contain current responses assigned for harmonically and intermodulation current peak. The large peaks were used to calculate the corrosion current density (icorr.), the Tafel slopes (βc and βa) and the causality factors CF-2&CF-3.[19, 20] Destructive method This method include DC potentiodynamic polarization technique which was used todetermine corrosion current density under steady state conditions by applying potential from-600 to +600 mV to obtain Tafel polarization curve and the result current is plotted as logarithm scale vs potential related to SCE, Extrapolating of two Tafel regions give (icorr.) and (Ecorr.) corrosion potential. By (icorr.) we able to calculate rate of corrosion (R) = 0.13(icorr.) (Equivalent weight)/ D where, D is density in g/cm 3 [21]. Equation (4) was used to determine IE% and Ɵ: IE% = θ x 100 = [1-(icorr / iocorr)] x 100 (4) Surface examination Preparation of C-steel surface by keeping the coupons for 24 hrsin 10% NH2SO3H in the presence and absence the extract, after abraded using different emery papers up to 2000 grade size then the coupons were washed gently with bidistilled water, carefully dried and mounted into desiccator without any further treatment. The corroded C-steel were examined using an X-ray diffractometer Philips (pw1390)with Cu-tube (Cu Ka1, I = 1.5405 A°), scanning electron microscope (SEM, JSM-T20, Japan). Results and Discussion Gravimetric Technique Weight loss of C-steel was determined at various time interval in the absence and presence of different concentrations on extract. Figure 2 shows the weight loss-time curves for C-steel in 10%NH2SO3H in the absence and presence of various concentrations of extract at 298 °K. This figure shows that the curves in the presence of the extract falls significantly below that of free acid. The calculated values of corrosion rate (k) and surface coverage(θ) and inhibition efficiency(IE %)obtained from weight loss measurement for various concentration of inhibitor in 10%NH2SO3H at 298-328°K are listed in Table. It is evident from this Table 2 and Figure 3 that the corrosion rate increased by increasing the temperature and the %IE increased by increasing the concentration of the extract and on the other hand, decreased by increasing the temperature. Table 1. Chemical composition (weight %) of C-steel Elements C Cr Ni Si Mn P S Fe Composition (weight %) 0.14 0.1 0.01 0.024 0.5 0.05 0.05 Rest A. S. Fouda et al./ Elixir Corrosion & Dye 91 (2016) 38510-38518 38512 80 100 120 140 160 180 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 W t lo s s ( m g c m -2 )