Different Concentrations Of PEG Research Articles

Effects of PEG-Induced Drought Stress and Different Boron Levels on Seed Germination and Seedling Growth Characteristics in Chickpea (Cicer arietinum L.) and Lentil (Lens culinaris Medik.)

In the present study, the drought tolerance potential of chickpea (Cicer arietinum L.) and lentil (Lens culinaris Medik.) seeds under different boron (B) levels were assessed. One chickpea (Azkan) and one lentil cultivar (Sahan) were selected for the genetic material. To provide drought condition, different level of polyethylene glycol solution (PEG 6000) was applied to seeds. Germination experiments were performed under PEG-induced stress to create water potentials of 0 (control), -2, and -4 MPa. Then, boron was applied as H3BO3 at 0 (control), 5, and 10 mM. The effects of these abiotic stresses were determined with the measurement parameters of germination rate and root traits. Drought stress adversely affected germination rate and seedling growth characteristics in chickpea and lentil. Especially, seed germination rate is extremely reduced by increased levels of drought stress. An increase in PEG levels from 0 to -4 MPa drastically decreased root and shoot width, and shoot length in chickpea whereas they did not generate a significant difference in seedling growth traits except for root width in lentil. Additionally, the results showed that increasing B treatments decreased the germination rate in both chickpea and lentil. The low concentration of B (5 mM) increased root and shoot length; however, a remarkable decrease was observed in root and shoot growth traits at the highest concentration of B (10 mM). The overall findings show that germination and seedling growth parameters were greatly inhibited by different concentrations of PEG and > 10 mM B levels for chickpea and lentil production.

Biophysical characterization of siRNA-loaded lipid nanoparticles with different PEG content in an aqueous system

Although lipid nanoparticles (LNP) are potential carriers of various pharmaceutical ingredients, further investigation for maintaining their stability under various environmental stressors must be performed. This study evaluated the influence of PEGylation and stress conditions on the stability of siRNA-loaded LNPs with different concentrations of PEG (0.5 mol%; 0.5 % PEG-LNP and 1.0 mol%; 1.0 % PEG-LNP) anchored to their surface. We applied end-over-end agitation, elevated temperature, and repeated freeze and thaw (F/T) cycles as physicochemical stressors of pH and ionic strength. Dynamic light scattering (DLS), flow imaging microscopy (FIM), and ionic-exchange chromatography (IEX) were to determine the degree of aggregation and change in siRNA content. The results indicate that 0.5 % PEG-LNP resisted aggregation only at low pH levels or with salt, whereas 1.0 % PEG-LNP had increased colloidal stability except at pH 4. 0.5 % PEG-LNP withstood aggregation until 71 °C and three cycles of F/T. In contrast, 1.0 % PEG-LNP maintained colloidal stability at 90 °C and seven F/T cycles. Moreover, 1.0 % PEG-LNP had higher siRNA stability under all stress conditions. Therefore, to ensure the stability of LNP and encapsulated siRNA, the PEG concentration must be carefully controlled while considering LNPs’ colloidal instability mechanisms under various stress conditions.

Early detection of local inbred of rice from Aceh to drought stressusing PEG 6000

This research was aimed to evaluate 7 local inbreds of rice from Aceh for their tolerance against drought stress through detection in their early development. The study employed a complet ely Randomized Design (CRD) Factorial comprising 2 factors: 1) inbred local rice Unsyiah Cakep (G1), Unsyiah Seumeulu (G2) and Unsyiah Mantap (G3), Sigunca (G4), Sigupai (G5), Cot Bada (G6), and Rajasa (G7) and (2) different concentrations of PEG 0, 20 and 25%. The results revealed that all variables contributed to the tolerance level of local inbred to drought stress. Local inbred Unsyiah Cakep and Unsyiah Mantap possessed longer roots longer than to her inbred. Laboratory assessment showed that there were 6 local inbred tolerant to drought stress, such as Unsyiah Cakep, Unsyiah Seumelu, Unsyiah Mantap, Sigupai, Cot Bada and Rajasa. Also, we found a susceptible inbred, Sigunca, with the application of PEG 6000 concentration of 20%.

Drought tolerance induction in wheat by inoculation of seeds with a novel growth-promoting bacteria

The use of Plant Growth Promoting Rhizobacteria (= PGPR) to increase crop tolerance to biotic and abiotic stresses such as drought is considered a novel method to increase plant yield. For this purpose, several rhizobacteria isolates from the wheat rhizosphere were screened in Northwest Iran. After sieving the bacteria in the media with PEG6000 5 g/100 ml (PEG= Polyethylene Glycol), a total of 22 bacterial isolates were selected for further experiment. The study was performed as a factorial experiment with three replications. The effect of selected bacterial isolates in three different concentrations of PEG (−0.5, −0.9, −1.2-1.2 MPa) on wheat seeds was evaluated under standard laboratory conditions for two weeks, and major growth factors were measured. After analyzing the data, to confidently conclude the selection of better bacteria, PCA (=Principal Component Analysis) was used for the importance of traits. The first and second components were 49.15% and 15.4% of the changes, respectively which justified all traits. In the first main component, germination percentage (PG), germination rate (GV) and seed vigor index (SV) traits had high coefficients which indicated the greater importance of these traits in justifying the general changes in traits. Finally, three bacterial strains were selected as the desired bacteria on the base of these traits for greenhouse work. The results indicated that all the three bacteria strains increased the mean value of the studied traits compared to that of the control. Among the three selected strains, the 16srDNA region of the bacterium with the best performance was sequenced. The sequencing results showed that this bacterium belonged to Bacillus wiedmannii with 98.8% Likelihood.

Utilization of co-precipitation method on synthesis of Fe3O4/PEG with different concentrations of PEG for biosensor applications

The synthesis of magnetite (Fe3O4) nanoparticles with the addition of polyethylene glycol-4000 (PEG-4000) was successfully carried out using a two-step co-precipitation method for the possible biosensor applications. In this study, different concentrations of PEG on Fe3O4/PEG (1:0, 4:1, 3:1, 2:1 and 1:1) were used. The crystallite size of the Fe3O4 decreased (14.35 to 12.83 nm) with the increase of PEG concentrations. The presence of a new carbonyl group in the samples indicates the presence of PEG in the Fe3O4. The weight loss percentage of the Fe3O4 increased from 7.7 to 41.46% with the increase of PEG concentrations. With the addition of PEG, Fe3O4 have a well-defined and homogeneous shape due to the presence of PEG which acts as a dispersing and stabilizing agent characterized. The magnetic properties showed that all samples exhibited superparamagnetic behavior. The saturation magnetization values of Fe3O4 decreased with increasing PEG layer and reached values ​​of 65.34 emu/g with zero remanent magnetization and coercivity field while maintaining the behavior superparamagnetism and high saturation magnetization. To evaluate the magnetic properties of the samples to the sensitivity of biosensor, GMR-biosensor was used. Five types of Fe3O4/PEG-alcohol solutions with a concentration of 50 μg/mL were dropped on the surface of the sensor. It was found that there was a decrease in the |ΔV| value with the increase of PEG concentrations, undergoing a linear function |ΔV| = 97.31x+1880.97. Thus, the remarkable fact of saturation magnetization and controllable particle size in these Fe3O4/PEG can serve as promising biosensor applications.

Influence of Boron and Drought Simulation on Germinability and Hardseededness of Black Medick Seeds (Medicago lupulina L.)

This study deals with the determination of germinability of black medick (Medicago lupulina L.) seeds in conditions of different drought intensity induced by different concentrations of PEG 8000 solutions (0.2; 0.4; 0.6 mol). Four batches of seed were tested (Ekola 2–5). At the same time, the influence of boron, some other elements (N, P, K, Ca, Mg, Zn, Cu, Mn) and compounds (starch, lipids and sugars) contents in black medick seeds on their germinability (percentages of germinated, dead and hard seeds) was evaluated. The effect of drought was manifested by germination which was reduced max. by 8% as compared with the control variant and was only partially significant. Statistically significant (P < 0.01) negative correlations (R = − 0.64) were recorded between germinability and the boron content in the seeds, and positive correlations were found between the percentages of hard seeds and the boron content in the seeds. The results show that the higher content of boron in the seeds of black medick increases the proportion of hard seeds at the expense of the germinated seeds percentages.

Expression of CrMPK3 and alkaloid synthesis genes with antioxidants in callus of Catharanthus roseus in response to polyethylene glycol

To improve the yield of secondary metabolites and understand the effects of PEG-induced drought stress on physiological and biochemical characteristics and the relationship between CrMPK3 and some genes of vinblastine biosynthesis pathway, PEG (0, 2.5%, 5%, and 10%) was applied in different exposure times (24 and 72 h) on callus of two cultivars (Alba and Rosea) of Catharanthus roseus. The increase in malondialdehyde and proline contents by increasing PEG concentration in both exposure times in Alba cultivar were more than in Rosea cultivar. Also, the activity of antioxidant enzymes including catalase (CAT), guaiacol peroxidase (GOPX), superoxide dismutase (SOD), glutathione peroxidase (GPX), and ascorbate peroxidase (APX) in the Alba cultivar was higher than the Rosea cultivar. The relative expression of vinblastine biosynthesis genes including STR, DAT, and PRX1 was significantly increased in both cultivars, especially in the medium with 5% PEG. However, the change of T16H gene expression was more minor. Vinblastine content confirmed the expression results of these genes at different concentrations of PEG after 24 and 72 h in both cultivars. The relative expression of CrMPK3 and catalase genes increased significantly in all media containing PEG. The highest expression of CrMPK3 and catalase genes was obtained after 24 and 72 h at 5% PEG in both cultivars, respectively. Finally, PEG can induce the accumulation of vinblastine in calli of C. roseus through a signaling pathway in which MAPK trigger the activation of antioxidant enzymes with up-regulation of the TIAs biosynthesis genes.

Antibacterial and Chemical Characterization of Silica-Quercetin-PEG Hybrid Materials Synthesized by Sol-Gel Route.

This paper aims to synthesize, via the sol–gel method, a biomaterial usable in the medical field. Here, the silica-PEG-quercetin system was evaluated in relation to the different concentrations of PEG (0, 6, 12, 24, 50 wt%) and quercetin (0, 5, 10, 15 wt%), respectively. In addition, Fourier Transform-Infrared spectroscopy (FT-IR), Scanning Electron Microscopy (SEM), and Kirby–Bauer analyses were performed. FT-IR was used to evaluate the hybrid formation and the influence of both PEG and Quercetin in the hybrid synthesized materials, SEM was used to evaluate the morphological properties, while the Kirby–Bauer test was used to understand the ability of the materials to inhibit the growth of the assayed bacterial strains (Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, and Staphylococcus aureus).

Evaluation of nitrogen fixers for drought tolerance and growth promotion in Tomato

Drought stress is one of the most fatal environmental phenomena that affect plant growth and productivity worldwide. In the present study, an attempt was made to screen and characterize nitrogen fixing bacteria for drought tolerance by inoculation in trypticase soy broth with different concentrations of PEG 6000. The strains were further evaluated for induction of drought tolerance and growth promotion in tomato. It was found that inoculation improved the plant physiological parameters of tomato seedlings. Furthermore, plants inoculated with nitrogen fixers viz., Microbacterium, Cellulosimicrobium and Paenibacillus showed better growth in terms of plant height, number of leaves, stem girth, root length, fresh and dry weight of plants and yield compared to uninoculated control plants under normal and reduced irrigation. The study demonstrates nitrogen fixers with plant growth promoting traits and drought tolerance can be a useful approach for the development of bioinoculants for drought stress management in crops.

&lt;i&gt;In-vitro&lt;/i&gt; Selection of Drought Stress Tolerance in Rice (&lt;i&gt;Oryza sativa&lt;/i&gt; L.) variety Tulasi and Sampada

In the present investigation, the tissue culture technique was used to develop drought tolerant varieties Tulasi and Sampada to a higher level of tolerance by two stage. First exposing the callus produced from the mature embryo to different concentrations of PEG (0.0, 1, 2 and 3) % and second selecting the best tolerant cells of the drought and obtaining plants from them. The plants tested with same concentrations of PEG, in normal conditions (pots) and evaluated by some indicators proline, carbohydrate, K, Na and Cl.

Effect of Salt and Osmotic Stresses on the Activity of Some Antioxidant Enzymes and Biochemical Traits in Catharanthus roseus

Abstract The experiment has been carried out in the Syrian National Commission of Biotechnology, during the growing season 2018/2019, to study the effect of abiotic stresses (salinity and osmotic stresses) on the activity of some antioxidant enzymes and biochemical traits in Catharanthus roseus. The experiment has been laid according to (CRD) with three replications. The seeds have been sterilized by NaOCl solution (0.5% v/v), then planted on MS medium. Plantlets have been moved to MS medium enriched with NAA (1 mg.L-1) and BA (2 mg.L-1). The callus has been initiated from leaves using MS medium containing NAA (1 mg L-1) and KIN (2 mg.L-1). After 60 days, callus has been transferred to MS medium supplemented with different concentrations of PEG 6000 (-0.2, -0.3, -0.4, -0.5 MPa), and NaCl (25, 50, 75, 100 mM) in succession as stimulating agents. The results show that the top value of solutes leakage has been in the salt and osmotic treatments (28.04 and 26.98% respectively) compared with the control (8.563%). MDA content has significantly been higher in salt stress (102.3 µmol.g-1 FW) followed by the osmotic stress treatment (79.41 µmol.g-1 FW), while it was significantly lower in the non-stressed treatment (37.76 µmol.g-1 FW). An increase in the proline content occurred in both the stress treatments (4.623, 4.243 mmol.g-1 FW, respectively) compared with the control (2.477 mmol.g-1 FW). The activity of antioxidant enzymes (CAT, APX, and SOD) have significantly been higher in salt stress treatment (506.9, 12270.02 mol.min-1.mg-1 protein, 191.4 U.mg-1 protein respectively), followed by osmotic stress (259.4, 7106.22 mol.min-1.mg-1 protein, 65.60 U.mg-1 protein, respectively), while it has been significantly lower in control (126.9, 1800.38 mol.min-1.mg-1 protein, 36.03 U.mg-1 protein, respectively).

​Screening of Chickpea (Cicer arietinum L.) Genotypes for Germination and Early Seedling Growth under PEG 6000 Induced Drought Stress

Background: Drought stress at germination and early growth stages hinders the seedling establishment in chickpea which ultimately affects the economic yield. Such adverse affects of drought can be mitigated by screening and identifying the tolerant genotypes of chickpea which is commonly cultivated under rain-fed conditions during post-rainy season. Methods: Effect of drought stress on germination and early seedling growth of thirty three chickpea genotypes was studied under four different concentrations of PEG 6000 (-0.3, -0.6, -0.9 and -1.2 MPa) along with control and hydration under laboratory conditions during 2018-19. Result: Significant variation was observed among the genotypes for germination, root length, shoot length and seedling vigour index under different concentrations of PEG 6000. Complete inhibition of germination was observed in most of the genotypes at -1.2 MPa. Based on the results obtained, JG 11 and NBeG 3 were considered as tolerant since they showed comparatively higher germination, root length, shoot length and seedling vigour even at -1.2 MPa, while NBeG 723 and NBeG 833 were considered as susceptible genotypes because of their poor germination and seedling growth even at lower levels of drought stress.

Priming seeds-method for increasing the germination of soybean seeds under drought stress conditions

Drought is one of the most important factors limiting the successful production of cultivated plants. One of the most sensitive stage to the water deficit in plants is seed germination. There are various methods of pre-sowing treatments that aim to reduce the negative impact of drought stress and improve seed germination. One of them is priming seeds. The aim of this experiment was to examine the effect of priming seeds in solutions - KNO3 (1%), ascorbic acid - AsA (100 mgl-1) and potassium chloride KCl (1%) on the reduction of the negative effect of drought stress. The effect of drought stress was simulated using different concentrations of PEG 6000 (0 (control), -0.30, -0.51, -0.80 MPa). The results of the research showed that with the increase of water deficiency, the effect of priming seeds is greater. At the water potential of the solution of -0.30 MPa, germination energy and seed germination increased on average by 6.77% and 5.08%, while at the water potential of the solution of -0.80 MPa, the increase was 19.28% and 16.75%, respectively. Also, priming seeds significantly reduced the intensity of lipid peroxidation and the content of free proline. From all the above, it can be concluded that priming of seeds is a method that can serve to improve the germination of soybean seeds in conditions of drought stress.

IN-VITRO SCREENING OF DIFFERENT TOMATO GENOTYPES AGAINST PEG INDUCED WATER STRESS

Tomato (Lycopersicum esculentum L.) is one of the most economically important plants in the Solanaceae family. Water scarcity is one of the major climatic constraints which is affecting all crops including tomato in the world. Selection of water stress tolerant cultivars is an important strategy to overcome this problem. Therefore the present research was conducted to determine the effect PEG induced water stress on germination percentage and early growth stages of tomato seedlings. Fifteen different tomato genotypes were screened under in-vitro conditions using two different concentrations of PEG (2% and 4%). The experiment was arranged in a completely randomized design (CRD) with three replications. Parameters like germination percentage (%), root length (cm), shoot length (cm) and seedling biomass (g) were recorded during the experiment. Results indicated that PEG induced water stress significantly reduced germination percentage (%) and other growth parameters in drought susceptible tomato genotypes (RUS-1, Rustam, R-2017, Pakit, 17904, Kashmiri, Kiara, Avinash, and K.K.2). Whereas in other genotypes “R. Wonder, Naqeeb, Rio grande, T-4, Patfeeder and Nagina” all parameters increase with an increase in PEG concentration. However among these genotypes, “Patfeeder” exhibited highest germination percentage (100 %) with maximum root and shoot length and seedling biomass at highest PEG concentration 4%. Based on experimental results, “Patfeeder” was considered a drought tolerant genotype due to its better performance in different levels of water stress.

Screening of Rice Apoplast Associated Endophytic Bacterial Isolates for Moisture Stress Tolerance and Plant Growth Promoting Traits

Investigations were made to identify, screen and characterize rice apoplastic fluid endophytic bacterial strains for osmotic stress tolerance and plant growth promoting activity. These bacterial strains were identified phylogentically as Bacillus subtilis TSAC5, Bacillus subtilis TSAA2, Bacillus sp. R2AA10, Bacillus cereus R2AA7, Bacillus marisflavi TSAC7, Cupriavidus alkaliphilus TSAC1, Delftia sp. TSAC2, Janibacter melonis R2AA1, Microbacterium oleivorans R2AA6, Kocuria rosea R2AA5, Pseudomonas aeruginosa NAAI3 and Sphingobium yanoikuyae R2AI1. Of these 12 strains, eight were obtained from drought tolerant rice varieties such as Anna R4 and IR DRT 64 and four from normal rice variety CO51. These endophytes exhibited varied level of osmotic stress tolerance created using different concentrations of PEG 6000 (-1.5, -3.0, -4.0, -4.5, -5.0 and -5.5 MPa) under in vitro conditions in liquid and solid medium. Among the 12 strains, Cupriavidus alkaliphilus TSAC1, Delftia sp. TSAC2, Bacillus marisflavi TSAC7, Janibacter melonis R2AA1, Kocuria rosea R2AA5, Pseudomonas aeruginosa NAAI3 and Sphingobium yanoikuyae R2AI1 showed moisture stress tolerance up to -5.5 MPa. Further increase in moisture stress of -6.0 MPa inhibited growth of 12 tested strains. These strains also exhibited Indole acetic acid (IAA), gibberellic acid (GA3) and extracellular polysaccharide (EPS) production and also showed ACC deaminase (ACCD) activity. Maximum extracellular proline production was found in Bacillus marisflavi TSAC7 under both normal and water stressed conditions. Higher IAA productivity was registered in Janibacter melonis R2AA1 followed by Cupriavidus alkaliphilus TSAC1 and Sphingobium yanoikuyae R2AI1 in the absence of PEG 6000. In the presence of PEG 6000 Delftia sp. TSAC2 recorded maximum IAA productivity. Bacillus subtilis TSAA2 showed greater ACC deaminase activity. EPS production was in the order of Pseudomonas aeruginosa NAAI3 followed by Sphingobium yanoikuyae R2AI1. Sphingobium yanoikuyae R2AI1 produced maximum quantity of GA3 both under normal and water stressed condition. None of the tested strains indicated insoluble phosphate, silicate and zinc solubilisation.

PEGylation of cationic liposomes encapsulating soluble Leishmania antigens reduces the adjuvant efficacy of liposomes in murine model.

Although there have been several attempts to develop a vaccine against leishmaniasis, no vaccine in human has been developed yet. Liposomes consisting of 1, 2-dioleoyl-3-trimethylammonium-propane (DOTAP) encapsulating soluble Leishmania antigens (SLA) enhance protective immunity of SLA against Leishmania major infection in mice. However, they immobilized at the injection site because of their positive charge. To overcome the problem, shielding the surface charge with polyethylene glycol (PEGylation) was chosen in this study. Liposomal SLA consisting different concentrations of PEG (1.9%-15% mol) were prepared. BALB/c mice were immunized three times in 3weeks intervals with different formulations. Lesion development and parasite burden in footpad and spleen were evaluated to specify the type of generated immune response and extent of protection. Th1/Th2 cytokine profiles and IgG isotypes were also analysed. The maximum protection was observed in mice immunized with Lip-SLA or pLip-SLA (1.9%) due to smaller footpad swelling, reduction in parasite load, an increase in IgG2a and IFN-γ production. Our results showed that immunization of mice with a high level of PEG (>7.5%) did not improve protective immunity of liposomal SLA. The presence of PEG, particularly more than 3.75%, is not recommended for protection against leishmaniasis.

Effects of carbohydrate source and polyethylene glycol on maturation and germination of somatic embryos in walnut (Juglans regia L.)

Low efficiency of somatic embryo maturation, germination, and conversion to plantlets is a major problem in many species including J. regia L. Germination efficiency of somatic embryos is very low in walnut. In this study, effects of two carbohydrate sources, sucrose and maltose (each at 3% and 6%), and two kinds of PEG (4000 and 6000) (each at four levels of 1.5%, 3%, 5% and 7.5%) on maturation and germination of walnut embryos were tested. The number of somatic embryos increased conspicuously on medium containing PEG. Furthermore, higher levels of PEG-4000 (7.5%) could remarkably enhance the morphogenesis of somatic embryos and the number of embryos produced. PEG-4000 stimulated somatic embryo maturation of walnut. This stimulatory effect was dependent on the carbohydrate source used. Sucrose in combination with PEG-4000 produced 50% of cotyledonary and normal somatic embryos. Different concentrations of PEG were effective on the number of embryos with a shoot meristem. PEG-4000 7.5% and sucrose 3.0% produced the highest rate (50.0%) of normal shooting embryos. However, PEG (4000, 6000) and maltose caused an unfavorable effect and increased the frequency of abnormal shaped somatic embryos.

English

Tamarind (Tamarindus indica L.) is a fruit species native to Equatorial Africa, India and Southeast Asia. Its seeds experience slow germination, thus, study on the influence of environmental factors, such as water and salt stresses, on seed germination, is required to assess the tolerance of these seeds to storage, and to maintain the vigor and the viability in the period between harvesting and sowing. The objective of this study was to evaluate the performance of tamarind seeds subjected to salt and water stresses and to storage. Three experiments were carried out in a completely randomized design with four replications of 25 seeds, totaling 100 seeds per treatment. For stress conditions, treatments consisted of moistening of the substrate with different concentrations of PEG 6000 (experiment 1) and NaCl (experiment 2) - 0 (control); -0.3; -0.6; -1.2. For the storage trial (experiment 3), seeds remained stored for 0 (control), 12, 24, 36 and 48 months. In the germination test, the percentage of germination, the speed of germination index, the mean speed and the mean germination time were assessed. All variables were influenced by the water and salt stress, and the seeds of tamarind sensitive to potential used in this work. As in the test with water and saline potential storage trials showed that the physiological seed quality was impaired when they were subjected to long storage period.   Key words: Tamarindus indica L, salinity, polyethyleneglycol, stress, storage.

Studies of miscibility and specific interactions of antitumor-active anhydride copolymer and poly(ethylene glycol) blends

The blending of polymers is of great interest, since the modification gives rise to diverse physical properties with the functionality of a polymer, without synthesis. Water-soluble antitumor-active poly(maleic anhydride-alt-acrylic acid) poly(MA-alt-AA) and poly(ethylene glycol) (PEG) blends were prepared by casting, and compatible properties were investigated by dilute solution viscometry. Viscosity measurements were made on ternary systems of polymer (1)/polymer (2)/solvent (H2O) and p-dioxane, at different concentrations of PEG and poly(MA-alt-AA). The interaction parameters Δβ, μ, Δk, Δb, β and α, which have been proposed, have been obtained using the viscosity data, to probe the miscibility of the polymer blends. The solid blends prepared were characterized with ATR-FTIR, 1H-NMR, DTA and TGA.

Adsorption behavior of poly(ethylene glycol) in the presence of two different kinds of halide ions, Br− and Cl− revealed using a microfluidic device and a flow cell type electrochemical quartz crystal microbalance

The adsorption behaviour of poly(ethylene glycol) (PEG) as an additive during Cu electrodeposition was investigated with a microfluidic device and a flow cell type electrochemical quartz crystal microbalance (EQCM). First, the current density (i) transition curves were measured by using the microfluidic device for rapid exchange from the base electrolyte to electrolytes with added Br− and different concentrations of PEG (cPEG) to determine the effective surface coverage ratio (θEFF) of the electrodes by PEG. Compared with Cl−, the most familiar additive for Cu electrodeposition, Br− produced a higher steady-state effective surface coverage ratio (θEFF,SS) and lower PEG adsorption rate constant (ka). Finally, the amount of increase in the weight on the electrode (Δm) by PEG in a Br−/PEG system was measured using an EQCM to calculate θEFF by Δm. The results revealed that the different capability of PEG to suppress i in the presence of Cl− and Br− depends on the Δm.