IHJPAS. 53 (4)2022 161 This work is licensed under a Creative Commons Attribution 4.0 International License. 0 Study the Efficiency of Poly Nicotine Amide as Anticorrosion Coating on Stainless Steel and Study Its Biological Activity Abctract Using an electrochemical polymerization technique at room temperature, poly nicotine amide (PNA) was produced from the monomer nicotine amide (NA) in aqueous solution. The structure of polymer layer generated on the stainless steel surface (316 L) (working electrode) is investigated by Fourier Transmission Infrared Region (FT-IR). The anti-corrosion activity of polymer coating on the stainless steel (SS 316 L) is investigated by electrochemical polarization in 0.20M solution of HCl at 293-323K. The graphene -modified polymer film-coated SS had greater protection efficiency (PE percent) when compared to Nano ZnO -modified polymer film- coated SS. For the corrosion process of SS 316 L, kinetic and thermo-dynamic parameters of activation are estimated. The antibacterial activity of coated film has been tested on both gram positive as well as gram negative bacteria by well diffusion approach, which include Staphylococcus aureus (Staph.Aure) and Ecoli. Through adding nanoparticles to a monomer solution to raise the effecincy of the polymer against the corrosion and bacterial, As a result, after modifying poly nicotine amide with nanomaterial, the inhibition zone values increased (Nano ZnO and Graphene). Keywords: corrosion, electrochemical polymerization, stainless steel, poly Nicotinamide, biological activity, nanomaterials, protection efficiency 1. Introduction The process of the electro-chemical polymerization involves oxidizing monomer for the purpose of producing radical, after that, those radical cations have been reacted with one another, or with some other monomer, the purpose of producing radical dimer that transferred to longer and trimer chain [1, 2]. Monomer Oxidation had happened on working electrode (WE) that is made of Article history: Received 12 May 2022, Accepted 27 June 2022, Published in October 2022. Sana A. Habeeb Departmentof Chemistry/ College of Science for women/ University of Baghdad/ Baghdad/ Iraq sana.a.h@ihcoedu.uobaghdad.edu.iq Doi: 10.30526/35.4.2856 Ibn Al-Haitham Journal for Pure and Applied Sciences Journal homepage: http://jih.uobaghdad.edu.iq/index.php/j/index Mayasa I.Ali Department of Chemistry, College of Science, University of Baghdad, Baghdad, Iraq. chemistmayasa@gmail.com https://creativecommons.org/licenses/by/4.0/ mailto:sana.a.h@ihcoedu.uobaghdad.edu.iq mailto:chemistmayasa@gmail.com IHJPAS. 53 (4)2022 162 a variety of the materials, like the indium tin oxide coated glass and stainless steel [3,4]. The conductive polymers have wide field in numerous applications, they are typically utilized in the rechargeable batteries, chemical transistors, producing indicators and ion selective electrodes, corrosion inhibitors and bio-chemical analyses [5-7]. Using the coating that has anti-microbial activities is one of the effective methods for the decrease of the microbial numbers on the health- care surfaces. The anti-microbial agents can be defined as materials having a capability to kill the pathogenic micro-organism [8]. Sufficient anti-microbial polymers have to be biocidal to a wide variety of the pathogenic micro-organism, may be re-generated in the case of activity loss, insolubility in the water for different applications, and inability of being de-composed into toxic substances [9]. In the present study, an electro-chemical polarization approach has been implemented for the purpose of studying protection efficiency of conductive polymer film upon SS corrosion in 0.20M of the HCl solution at temperature that ranges between 293 and 323 K. The effects of the addition of the Nano-materials (ZnO (Nano) and Graphene) upon anti-corrosion actions of polymer films on the SS surfaces are studied. *corresponding author email:chemistmayasa@gmail.com 2. Experimental part 2.1. Preparation of samples The sample used in this work is SS 316, which diameter disk 2.2 cm prepared according to the following steps:- Step one:- the samples were polished by different grade of silicone carbide include (800,1200 and 2000 mesh grit), and after that, washed with the distilled water and acetone and kept it in desiccator. Step two:- the sample was immersed in monomer solution (nicotine amide) which is (0.1 g) of nicotine amide in (100ml) of H2O with adding 3 drop ps of (98% conc.H2SO4) to increase conductivity of the solution at room temperature for electrochemical polymerization process by DC power supply [10]. Step three:- addition of nanomaterial, the nanomaterial used in this work are (0.04 g of Nano ZnO) and (0.004 g of Graphene) to improve the efficiency of the polymer film against corrosion and bacterial. 2.2. Corrosion measurement The tests of corrosion have been carried out with an advanced potentio-stat (Winking MLab200, Bank Electronic–Intelligent controls GmbH, Germany) complete with all of the accessories, including a cell, electrodes (working electrode, reference electrode, and auxiliary electrode), and a working electrode holder. Corrosive media was a 0.2 M HCl solution, and curves of polarization have been scanned from (-200mv) to (+200mv) from open circuit potential, corrosion currents, and corrosion potentials. Ecorr have been calculated with extrapolating anodic and cathodic Tafel lines from the curves of polarization at 4 temperature degrees: 293, 303, 313, and 323K. IHJPAS. 53 (4)2022 163 2.3. Biological activity In this work, the prepared polymer (poly nicotine amide) (800 µg/ml) evaluated for biological activities towards gram-positive bacteria (S.aureus) as well as the gram negative bacteria (Ecoli). Well diffusion approach that has been utilized for the determination of inhibition potential of the prepared poly nicotine amide against bacterium and the used solvent is Dimethyl Sulfoxide (DMSO). 3. Results and Discussions 3.1. Fourier Transform Infrared Region (FTIR) for monomer and polymer The asymmetric and symmetric stretching vibrations of NA (monomer) resulted in two absorption bands at (3335.13 and 3238.40) cm-1 (-NH2). Other absorption bands at (1525.5 and 1618.23) cm- 1 are a result of (C=N) imine, (C=C) aromatic, and other absorption bands at (1525.5 and 1618.23) cm-1 are a result of the (C=N) imine, (C=C) aromatic, respectively. PNA (polymer) exhibited bands of absorption at (3448, 3425) cm-1 as a result of (O-H) carboxyl and (N-H) amide, as well as absorption bands at (1718.48 and 1668) cm-1 due to (C=O) carboxyl and (C=O) amide [11,12]. Table1: FT-IR spectral data (cm-1) for monomer (NA) Monomer (NA) Absorption band intensity (cm-1) Functional group 3335.13& 3238.40 ν N-H 3065.53 Aromatic C-H 1690.8 C=O (amide) 1618.23 Aromatic C=C 1525.5 C=N Polymer (PNA) 3453.13 ν O-H 3425 ν N-H 2914.24 & 2898.81 Aliphatic C-H 1718.48 C=O (carboxyl) 1668 C=O (amide) 3.2 Corrosion measurements Figure 1 shows the impact of a polymeric layer upon cathodic and anodic curves of polarization of SS in 0.2M solution of HCl at temperatures ranging from 293K to 303K in the absence and presence of nanomaterial. Extrapolation Tafel lines were used to determine the corrosion current density. Table 2 shows effects of a polymeric layer in the presence and absence of the nanoparticles. Corrosion potential (Ecorr), cathodic Tafel slope (c), corrosion current density (icorr), and anodic Tafel slope (a) were discovered to be corrosion characteristics. The following equation [13] is used to calculate protection efficiency: %PE = (icorr)o−(icorr) (icorr)o ∗ 100 (1) Where the (icorr)o represents current density of the corrosion for the uncoated SS, (icorr) the density of the corrosion current for the coated SS. Corrosion potential (Ecorr) has been shifted to more positive values (i.e. towards the noble direction) and icorr has been reduced after adding the Nano-materials. The resistance of polarization (Rp) has been determined by the Stern-Gerry eq. [14]: Rp = ba+bc 2.303 (ba+bc)icorr (2) IHJPAS. 53 (4)2022 164 The measurements of the polarization resistance (Rp) have similar requirements to full polarization curve measurements and it has been considered beneficial as one of the methods for the identification of the corrosion upsets and initiate the remedial actions [15]. Rp values have been presented in Table 1. -500 -400 -300 -200 -100 0 100 -3 -2.5 -2 -1.5 -1 -0.5 0 p o te n ti a l (m V ) icorr (µA/cm2) 293K 303K 313K 323K a -500 -400 -300 -200 -100 0 100 200 0.00001 0.0001 0.001 0.01 0.1 1 p o te n ti a l (m V ) icorr (µA/cm2) 203K 303K 313K 323Kb -400 -300 -200 -100 0 100 200 0.0001 0.001 0.01 0.1 1 P o te n ti a l (m V ) icorr (µA/cm2) 293K 303K 313K 323K c IHJPAS. 53 (4)2022 165 Figure1.Tafel plot for: a) uncoated SS, b) coated SS with polymer film, c) coated SS with the polymer film that has been modified by Nano ZnO, d) coated SS with polymer film that has been modified with the graphene. Table2. Parameters of corrosion for the coated as well as the uncoated SS in 0.20M solution of the HCl 3.3. Kinetic and Thermo-dynamic Parameters of Activation The thermo-dynamic parameters of activation include energy of activation Ea, activation entropy S* and activation enthalpy H* that have been computed with the use of Arrenhius eq. and its alternative formulation that has been referred to as the state of transition, and the energy of activation has been determined from plot which represents correlation between the Log icorr and reciprocal of the absolute degree of the temperature (1/T) [16]. 𝐋𝐨𝐠 𝐢𝐜𝐨𝐫𝐫 = 𝐋𝐨𝐠 𝐀 − 𝐄𝐚 𝟐.𝟑𝟎𝟑𝐑𝐓 (3) icorr: represents the current density of corrosion, A: represents pre-exponential factor, Ea: represents energy of activation, R: represents gas constant (8.315JK-1mol-1), T: denotes absolute temperature (K). whereas the state of transition is represented by the equation below[17]: -300 -200 -100 0 100 200 300 0.00001 0.0001 0.001 0.01 0.1 1 p o te n ti a l (m V ) icorr(µA/cm2 293K 303K 313K 323K d Coating T/K -Ecorr [mV] Icorr [µA/cm²] - βc mV/De c βa [mV/Dec] PE% WL [g/m²d] PL [mm/y] Rp [Ω.cm2] Uncoated SS 293 116.7 18.42 188.7 159.8 - 1.48 0.20 2039..681 303 126.0 21.37 199.1 185.8 - 1.72 0.23 1952.858 313 206.6 24.35 207.7 220.5 - 1.96 0.27 1906.821 323 271.8 25.89 171.6 258.5 - 2.08 0.28 1729.746 Coated SS with PNA 293 68.7 4.09 112.6 100.0 77.796 0.033 0.004 5622.868 303 72.3 6.47 134.8 144.4 69.724 0.052 0.007 4678.897 313 132.4 7.44 137.1 141.4 69.446 0.059 0.008 4062.513 323 210.6 8.21 153.6 166.1 68.250 0.066 0.009 4220.667 Coated SS with PNA modified with nano ZnO 293 48.9 3.29 93.3 108.0 82.139 0.265 0.036 6606.505 303 89.4 4.48 97.7 94.1 79.036 0.361 0.049 4645.833 313 117.7 6.60 125.4 120.3 72.895 0.531 0.072 4039.43 323 163.5 7.39 129.5 136.4 71.456 0.595 0.080 3903.259 Coated SS with PNA modified with Graphene 293 10.5 0.472 185.4 255.5 97.438 0.038 0.005 98838.15 303 58.6 0.529 335.5 254.2 97.525 0.043 0.006 118710 313 87.1 0.606 148.8 256.5 97.511 0.049 0.007 67475.66 323 125.3 0.813 215.8 319.0 96.859 0.066 0.009 68748.98 IHJPAS. 53 (4)2022 166 Log icorr T = Log [ R Nh + ΔS∗ 2.303R ] − ΔH∗ 2.303RT (4) N denotes the Avogadro's number (6.0220 1023mol) and h is the Blanks constant (6.620 10-34JS). The activation entropy S* and enthalpy H* have been calculated using plot in Figure 3 that depicts correlation between log (icorr/T) and reciprocal of absolute temperature (1/T). Where the intercept is (Log (R/Nh) + S*/2.303 R) and slope is (- H*/2.303RT). The activation free energy is computed with the use of the equation below: ∆G* = ∆H* -T∆S* (5) Figure 2.Plot of log icorr versus 1/T for uncoated and coated SS with polymer film absence and presence of nano- materials in 0.20M HCl Figure 3. Plot of log icorr/T versus 1/T for coated SS with polymer film with presence and absence nano-material in 0.20M HCl -0.6 -0.4 -0.2 0 0.2 0.4 0.6 0.8 1 1.2 1.4 1.6 0.00305 0.0031 0.00315 0.0032 0.00325 0.0033 0.00335 0.0034 0.00345 Lo g i co rr ( µ A /c m 2 ) 1000/T(K-1) PNA PNA + nano ZnO PNA + Graphene uncoated SS 316L -3 -2.5 -2 -1.5 -1 -0.5 0 0.00305 0.0031 0.00315 0.0032 0.00325 0.0033 0.00335 0.0034 0.00345 Lo g i co rr /T ( µ A /c m 2 .K ) ((1000/T PNA PNA+nano ZnO PNA + Graphene uncoated SS316L IHJPAS. 53 (4)2022 167 Table3. Transition state thermo-dynamic parameter at a variety of the temperature degrees for corrosion of coated as well as uncoated SS with polymer film in presence and absence of nano-materials in 0.20M HCl solution Coating R2 Ea kJ.mol- 1 A/Molecule. Cm-2S-1 R2 ∆H* KJ. K-1mol- 1 -∆S* J.K-1mol-1 ∆G KJ. K-1mol-1 Uncoated SS316L 0.9789 9.103 4.721*1026 0.958 6.546 198.112 64.593 66.574 68.555 70.536 Coated SS with PNA 0.981 17.726 3.901*1023 0.855 15.169 199.737 73.692 75.689 77.687 79.684 Coated SS with PNA+ nano ZnO 0.969 22.242 1.861*1028 0.961 19.685 186.745 74.401 76.269 78.136 80.004 Coated SS with PNA+Graphene 0.932 13.808 7.878*1025 0.903 11.252 201.342 70.245 72.259 74.272 76.285 Thermodynamic activation values (Ea & H*) for polymer layer on SS surface were higher than for SS uncoated by polymer film, indicating that the energy barrier was increased. The activation entropy values for SS coated with polymer film and SS uncoated with polymer film are negative, indicating that activated complex in rate-determining step has been an association instead of a dissociation step, and that disordering which happens in the case of going from the reactants to the activated complex has been decreased [18]. Table 3 shows that the free energy activation has positive values and that the change with rising temperature is essentially negligible, which indicates that activated complex isn’t stable and that a chance of its creation decreases with increasing the degree of the temperature. 3.4 Biological Activity Results have demonstrated that PNA inhibited Staph.Aures and E.coli effectively at concentrations of 800 g/ ml, as shown in Table 4. The role of stable complex that has been generated between cleaved DNA and drug-bound topoisomerases is thought to be responsible for the polymer's capacity to kill bacteria. However, because of its capacity to disrupt the drug–DNA combination, topoisomerase inhibition may have serious ramifications for the cell. As a result of their high ratio of surface area to volume (S/V) and compact sizes, nanomaterials are regarded biocidal effective materials [19,20]. As a result, after modifying poly nicotine amide with nanomaterial, the inhibition zone values increased (Nano ZnO and Graphene). IHJPAS. 53 (4)2022 168 Table 4. Anti-microbial activity of polymer in the presence and absence of the nano-materials. Compounds Stap.Aure (gram positive)(mm) E.coli (gram negative) (mm) PNA 15 14 PNA modified with Graphene 18 18 PNA modified with nano ZnO 18 17 Amoxicillin 30 30 4. Conclusions With rising temperature, corrosion current density (icorr) and corrosion potential (Ecorr) increased. In absence and presence of a nanomaterial, corrosion current density (icorr) has been reduced after covering SS with a layer of polymer. In presence and absence of nano-material, corrosion potential (Ecorr) of SS that has been coated with polymer film shifts to higher position than that of uncoated SS, which implies that polymer film works as anodic protection. 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