Electrochemical oxidation of nitrite on nanodiamond powder electrode

Nanodiamond (ND) powder electrodes were fabricated and the electrochemical properties were investigated in the solution containing nitrite in this article. This electrode exhibits substantial catalytic ability toward the oxidation of nitrite anions. The electrochemical oxidation mechanism of nitrite on the ND powder electrode is discussed. The oxidation of NaNO₂ is a two-electron transfer process. The electrode reaction rate constant k is estimated to be 2.013 × 10⁻⁴ cm/s and (1 − α)n_α is 0.1643. The peak current increases linearly with the rising of the concentration of NaNO₂.     

Electrocatalytic reduction of nitrite using ferricyanide; Application for its simple and selective determination

The electrocatalytic reduction of nitrite has been studied by ferricyanide at the surface of carbon paste electrode. Cyclic voltammetry and chronoamperometry techniques were used to investigate the suitability of ferricyanide as a mediator for the electrocatalytic nitrite reduction in aqueous solution with various pH. Results showed that pH 0.00 is the most suitable for this purpose. In the optimum pH, the electrocatalytic ability about 700 mV can be seen and the homogeneous second-order rate constant (k_s) for nitrite coupled catalytically to ferricyanide was calculated 2.75 × 10³ M⁻¹ s⁻¹ by Nicholson-Shain method. Also, electron transfer coefficients (α) for ferricyanide was determined by using various electrochemical approaches such as Tafel plot in the absence and presence of nitrite 0.556 and 0.760, respectively. The catalytic reduction peak current was linearly dependent on the nitrite concentration and the linearity range obtained was 5.00 × 10⁻⁵ to 1.00 × 10⁻³ M. Detection limit has been found to be 2.63 × 10⁻⁵ M (2σ). This method has been applied as a selective, simple and precise method for determination of nitrite in real sample.     

Inhibitory effect of tungstate, molybdate and nitrite ions on the carbon steel pitting corrosion in alkaline formation water containing Cl ion

The pitting corrosion of carbon steel in carbonate-formation water solution in the presence of chloride ions and the effect of addition WO₄²⁻, MoO₄²⁻ and NO₂⁻ anions on the pitting corrosion were studied using cyclic voltammetry and potentiostatic current-time measurements and complemented by scan electron microscope (SEM), energy dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) investigations. Cyclic voltammograms of carbon steel in the presence of chloride ions in carbonate-formation water solution show one anodic peak, corresponding to the formation green rust carbonate and the two cathodic peaks. As the addition of Cl⁻ ions concentration increases, the anodic peak current density increases and pitting potential E_pit shifts to more negative potential. It is shown that the rate of pit initiation () decreases and the pitting potential E_pit moves to more positive direction upon the addition of inorganic anions. It was found that pitting inhibition of carbon steel increases in the sequence: (WO₄)²⁻ > (MoO₄)²⁻ > (NO₂)⁻.     

Electrochemical study of the intermolecular electron transfer to Pseudomonas aeruginosa cytochrome cd1 nitrite reductase

The kinetics of electron transfer reaction between cytochrome cd₁ nitrite reductase (NiR) from Pseudomonas aeruginosa and various physiological/non physiological redox partners was investigated using cyclic voltammetry at the pyrolytic graphite electrode. While NiR did not exchange electron with the electrode, cytochrome c₅₅₁ and azurin, both from Ps. aeruginosa, behaved as fast electrochemical systems. The intermolecular electron transfers between NiR and cytochrome c₅₅₁ or azurin as electron shuttles, in the presence of nitrite, were studied. Second order rate constants of 2×10⁶ and 1.4×10⁵ M⁻¹ s⁻¹ are calculated for cytochrome c₅₅₁ and azurin, respectively. The dependence of the second-order rate constant on ionic strength and pH is discussed. Finally, the effect of the global charge of the electron shuttles was explored using differently charged species (proteins or small ions). The experimental results suggest involvement of polar interactions as well as of hydrophobic contacts in the protein recognition prior to the intermolecular electron transfer. As the cross-reaction between Ps. nautica cytochrome c₅₅₂ and Ps. aeruginosa NiR was shown to be as efficient as the catalytic reaction involving the physiological partners, it is concluded to a ‘pseudo-specificity’ in the recognition between NiR and the electron donor.     

Nitrate and nitrite electrocatalytic reduction on Rh-modified pyrolytic graphite electrodes

The electrochemical reduction of nitrate and nitrite anions was investigated on Rh-modified pyrolytic graphite electrodes prepared by potentiostatic electrodeposition with the use of a double-pulse technique. Several important parameters (pH, temperature and composition of electrolytic medium, electrolysis potential) were varied. Only ammonia and nitrite ions were detected among NO₃⁻ reduction products, while NO₂⁻ ions are straightforwardly reduced to ammonia. The experimental data (CV measurements and the results of electrolyses) clearly show that Rh/graphite electrodes are much more efficient for NO₂⁻ reduction than for that of NO₃⁻ at room temperature which was confirmed by the determination of rate constants of corresponding reactions and the activation energy of NO₂⁻ reduction. The influence of carboxylate anions and tetraalkylammonium cations on the electrocatalytic activity of Rh/graphite electrodes was investigated and the inhibiting effect of HCOO⁻ anions on hydrogen evolution reaction and nitrate reduction was demonstrated.     

Electrochemical nitrite nanosensor developed with amine- and sulphate-functionalised polystyrene latex beads self-assembled on polyaniline

Aniline doped with polyvinyl sulphonate (PV-SO₃⁻) was electropolymerised on screen printed carbon (SPCE) and glassy carbon (GCE) electrodes. Then nano-structured polystyrene (PS_NP) latex beads functionalised with amine (PS_NP-NH₂) and sulphate (PS_NP-OSO₃⁻) were self-assembled on the modified SPCE and GCE. The resultant polyaniline nanocomposites (PANI|PS_NP-NH₂ or PANI|PS_NP-OSO₃⁻) were characterised by cyclic voltammetry (CV), UV-vis spectroscopy and scanning electron microscopy (SEM). Brown-Anson analysis of the multi-scan rate CV responses of the various PANI films gave surface concentrations of the order of 10⁻⁸ mol cm⁻². UV-vis spectra of the PANI films dissolved in dimethyl sulphoxide showed typical strong absorbance maxima at 480 and 740 nm associated with benzenoid π-π* transition and quinoid excitons of polyaniline, respectively. The SEM images of the PANI nanocomposite films showed cauliflower-like structures that are <100 nm in diameter. When applied as electrochemical nitrite sensor, sensitivity values of 60, 40 and 30 μA/mM were obtained for electrode systems containing PANI|PS_NP-NH₂, PANI and PANI|PS_NP-SO₃⁻, respectively. The corresponding limits of detection of the sensors were 7.4, 9.2 and 38.2 μM NO₂⁻.     

Silver(I) complexes with 1′-(diphenylphosphino)-1-cyanoferrocene and nitrite or nitrate supporting ligands

The reactions of 1′-(diphenylphosphino)-1-cyanoferrocene (1) and silver(I) salts with common oxoanions, viz. AgNO₃, AgNO₂ and Ag₂SO₄, led to defined products only in the case of AgNO₃ and AgNO₂. Whereas the reactions involving silver(I) nitrate produced the phosphine complex [Ag(NO₃-κ²O,O′)(1-κP)₂] (2) irrespective of the metal-to-ligand ratio, those with AgNO₂ gave rise to the coordination polymer [Ag{μ(P,N)-1}(NO₂-κ²O,O′)]_n (3) and the discrete monosilver complex [Ag(NO₂-κO,O′)(1-κP)₂] (4) at the Ag:1 molar ratios 1:1 and 1:2, respectively. Compounds 2–4 were structural characterized by spectroscopic methods and by single-crystal X-ray diffraction analysis.     

Enhanced luminescence of novel Ca3B2O6:Dy phosphors by Li-codoping for LED applications

The Ca_3−xB₂O₆:xDy³⁺ (0.0 ≤ x ≤ 0.105) and Ca_2.95−yDy_0.05B₂O₆:yLi⁺ (0 ≤ y ≤ 0.34) phosphors were synthesized at 1100 °C in air by solid-state reaction route. The as-synthesized phosphors were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), photoluminescence excitation (PLE) and photoluminescence (PL) spectra. The PLE spectra show the excitation peaks from 300 to 400 nm is due to the 4f-4f transitions of Dy³⁺. This mercury-free excitation is useful for solid state lighting and light-emitting diodes (LEDs). The emission of Dy³⁺ ions upon 350 nm excitation is observed at 480 nm (blue) due to the ⁴F_9/2 → ⁶H_15/2 transitions, 575 nm (yellow) due to ⁴F_9/2 → ⁶H_13/2 transitions and a weak 660 nm (red) due to ⁴F_9/2 → ⁶H_11/2 emissions, respectively. The optimal PL intensity of the Ca_3−xB₂O₆:xDy³⁺ phosphors is found to be x = 0.05. Moreover, the PL results from Ca_2.95−yDy_0.05B₂O₆:yLi⁺ phosphors show that Dy³⁺ emissions can be enhanced with the increasing codopant Li⁺ content till y = 0.22. By simulation of white light, the CIE of the investigated phosphors can be tuned by varying the content of Li⁺ ions, and the optimal CIE value (0.300, 0.298) is realized when the content of Li⁺ ions is y = 0.22. All the results imply that the Ca_2.95−yDy_0.05B₂O₆:yLi⁺ phosphors could be potentially used as white LEDs.     

Probing the electrochemical behaviour of SWCNT-cobalt nanoparticles and their electrocatalytic activities towards the detection of nitrite at acidic and physiological pH conditions

The electrochemical decoration of edge plane pyrolytic graphite electrode (EPPGE) with cobalt and cobalt oxide nanoparticles integrated with and without single-walled carbon nanotubes (SWCNTs) is described. Successful modification of the electrodes was confirmed by field emission scanning electron microscopy (FESEM), AFM and EDX techniques. The electron transfer behaviour of the modified electrodes was investigated in [Fe(CN)6]^3−/4− redox probe using cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) and discussed. The study showed that cobalt nanoparticles modified electrodes exhibit faster electron transfer behaviour than their oxides. The catalytic rate constant (K) obtained at the EPPGE-SWCNT-Co for nitrite at pH 7.4 and 3.0 are approximately the same (∼3 × 10⁴ cm³ mol⁻¹ s⁻¹) while the limits of detection (LoD = 3.3δ/m) are in the μM order. From the adsorption stripping voltammetry, the electrochemical adsorption equilibrium constant β was estimated as (13.0 ± 0.1) × 10³ M⁻¹ at pH 7.4 and (56.7 ± 0.1) × 10³ M⁻¹ at pH 3.0 while the free energy change (ΔG°) due to the adsorption was estimated as −6.36 and −10.00 kJ mol⁻¹ for nitrite at pH 7.4 and 3.0, respectively.     

Empirical determination of equation of state for zero internal pressure in rare gas solids and semi-crystalline polymers

An equation of state for zero internal pressure in rare gas solids and semi-crystalline polymers has been determined based on the empirical functions of thermal pressure coefficient γ_V with respect to volume at constant pressure. The experimental data of PVT over wide range of temperature and pressure published by Anderson and Swenson and Syassen and Holzapfel for rare gas solids and Olabisi and Simha and Zoller for semi-crystalline polymers are used to evaluate γ_V. The function of γ_V with respect to volume determined at constant pressure is given by where V₀ is the volume at 0 K, A, ? and c are constants. The function of internal pressure P_i = γ_VT − P with respect to temperature at constant pressure is determined by converting the function of γ_V(V) to a function of temperature γ_V(T). An empirical equation of state for zero internal pressure determined by pressure P^∗, volume V^∗ and temperature T^∗ at which P_i = 0 is expressed by P^∗V^∗/RT^∗=C^∗−D^∗V^∗ for rare gas and semi-crystalline polymer where C^∗ and D^∗ are constants. The practical meaning of the equation of state for P_i = 0 in the semi-crystalline polymers has been discussed.     

Separation performance of a nanofiltration membrane influenced by species and concentration of ions

Nanofiltration (NF), which has been largely developed over the past decade, is a promising technology for the treatment of organic and inorganic pollutants in surface and ground waters. The ESNA 1 membrane from the Nitto Denko Corporation of Japan is made of aromatic polyamide, which provides salt rejection from 50% to 90%. In this paper permeation experiments of aqueous solutions of five chlorides (NH₄Cl, NaCl, KCl, MgCl₂ and CaCl₂), three nitrates (NaNO₃, Mg(NO₃)₂ and Ca(NO₃)₂), and three sulfates (NH₄)₂SO₄, Na₂SO₄ and MgSO₄) were carried out. The effects of species and concentration of salts on the separation performance of the ESNA 1 membrane were investigated. The experimental results showed that the rejection to most salts by the ESNA 1 membrane decreased with the growth of the concentration. Then, the reflection coefficient and solute permeability of ESNA 1 membrane were calculated by the Spiegler-Kedem equation from experimental data. The reflection coefficients of the ESNA 1 membrane to salts are all above 0.95. The salt permeabilities, except for magnesium and calcium salts, increased with the growth of concentration. The sequence of rejection to anions by the ESNA 1 membrane is R(SO²⁻₄) > R(Cl⁻) > R(NO⁻₃) at the same concentration which ranges from 10 mol/m³ to 100 mol/m³. The sequence of rejection to anions by the ESNA 1 membrane can be written as follows: R(Na⁺) > R(K⁺) > R(Mg²⁺) > R(Ca²⁺) at 10 mol/m³ concentration and R(Mg²⁺) > R(Ca²⁺) > R(Na⁺) > R(K⁺) at 100 mol/m³ concentration.     

Microstructure of free volume in SMA copolymers II. Local free volume from PALS

The structure of the free volume and its temperature dependence between, at maximum 133 and 503 K of copolymers of styrene with maleic-anhydride, SMA (0-35 mol% MA), is studied by pressure-volume-temperature (PVT) experiments and positron annihilation lifetime spectroscopy (PALS). In this second part of the work, PALS data are reported from which the temperature dependence of the mean size and size distribution of local free volumes (subnanometer size holes) is analysed. The mean hole volume, ν_h, varies in PS between 80 Å³ (133 K) and 212 Å³ (503 K) and shows a systematic decrease with increasing MA content for a given temperature above T_g. The specific number of holes, N_h′, estimated from a comparison of PVT and PALS results, increases slightly with MA content from N_h′=(0.60±0.02)×10²¹ g⁻¹ to N_h′=(0.70±0.02)×10²¹ g⁻¹ which corresponds to N_h(T_g)=N_h′/V_g=0.62-0.82 nm⁻³ (V_g is the material's specific volume at T_g) and 1/N_h(T_g)=1.6-1.2 nm³ for the volume which contains one hole. The analysed size distributions of the holes above T_g follow the compressibility of the free volume as it is predicted by the theory of thermal volume fluctuation. We also comment on the connection between the hole size as measured by PALS and the size of a cluster of randomly distributed unoccupied cells as defined by the Simha-Somcynsky theory.     

Polymer supported nitrite esters as diazotising reagent

Summary Glycidyl methacrylate based terpolymer resin was prepared in spherical beads form by suspension polymerization of glycidyl methacrylate (0.4mol)-methyl methylacrylate (0.5mol)-divinyl benzene (0.1mol) mixture. Acid catalysed reaction of the resin beads (110–220 μm ) with excess of glycerol gives corresponding modified resin with hydroxyl functions ( 6.86 mmol g⁻¹). Upon standing in 2 M HNO₂ solution, hydroxyl groups of the later esterified with nitrous acid (3.55 mmol g⁻¹). The nitrite ester functions of the resin have been demonstrated to be efficient nitrous acid precurser in diazotisation of aromatic amines. Diazotisation of aniline in 2 M HCl solutions at 0°C takes place in less than 15 minutes. Applicability and pratical yields of the method presented have been investigated by diazo coupling reaction of β- naphthol. Received: 8 June 2000/Revised version: 6 February 2001/Accepted: 28 February 2001     

Synthesis of star polymer by means of the living polymerization of [(o-trifluoromethyl)phenyl]acetylene using a MoOCl4-based catalyst and the linking method

A star polymer was synthesized by addition of 1,4-diethynyl-2,5-dimethylbenzene as linking agent (30 °C, 24 h) after living polymerization of [(o-trifluoromethyl)phenyl]acetylene (o-CF₃PA) with MoOCl₄-n-Bu₄Sn-EtOH catalyst (in anisole, 30 °C, 20 min; [Mo]=10 mM, [P^∗]/[Mo]=40%, [o-CF₃PA]₀=200 mM). The M_n values of the living and star polymers were 8.1×10³ and 5.3×10⁴, respectively, according to gel permeation chromatography, while these values determined by multi-angle laser light scattering (MALLS) were 7.8×10³ and 2.5×10⁵. The M_w/M_n and arm number of the star polymer were 1.04 and 29, respectively, according to MALLS. The molecular weight and arm number of star polymer increased with increasing linking agent concentration and polymerization temperature.     

Study of Fe/Fe ratio in thin films of carbonate or sulphate green rusts obtained by potentiostatic electrosynthesis

Thin films of carbonate or sulphate green rusts were synthesised from potentiostatic oxidation of solutions containing ferrous species and bicarbonate or sulphate ions at slightly alkaline pHs and ambient temperature. The thin films were characterised by means of electrochemical quartz crystal microbalance, scanning electron microscopy, X-ray diffraction and infrared reflection-absorption spectroscopy. The composition of carbonate or sulphate green rusts was studied through chemical titration, inductively coupled plasma-optical emission spectroscopy (ICP-OES) and gravimetry and is as follows:

[Fe^II_(2R)Fe^III₂(OH)_{(4R−2R′+6)}(H₂O)_(2R′−2)]^2R′+·[R′CO₃,(2R-{3 or 4}R′ + 2)·H₂O]^2R′− and [Fe^II_(2R)Fe^III₂(OH)_{(4R−2R″+6)}(H₂O)_(2R″−2)]^2R″+·[R″SO₄,(4R − 4R′ + 4)·H₂O]^2R″−     

Room temperature living cationic polymerization of styrene with HX-styrenic monomer adduct/FeCl3 systems in the presence of tetrabutylammonium halide and tetraalkylphosphonium bromide salts

Living cationic polymerization of styrene was achieved with a series of initiating systems consisting of a HX-styrenic monomer adduct (X = Br, Cl) and ferric chloride (FeCl₃) in conjunction with added salts such as tetrabutylammonium halides (nBu₄N⁺Y⁻; Y⁻ = Br⁻, Cl⁻, I⁻) or tetraalkylphosphonium bromides [nR′₄PBr; R′ = CH₃CH₂-, CH₃(CH₂)₂CH₂-, CH₃(CH₂)₆CH₂-] or tetraphenylphosphonium bromide [(C₆H₅)₄PBr] in dichloromethane (CH₂Cl₂) and in toluene. Comparison of the molecular weight distributions (MWDs) of the polystyrenes prepared at different temperatures (e.g., −25 °C, 0 °C and 25 °C) showed that the polymerization is better controlled at ambient temperature (25 °C). The polymerization was almost instantaneous (completed within 1 min) and quantitative (yield ∼100%) in CH₂Cl₂. In CH₂Cl₂, polystyrenes with moderately narrow (M_w/M_n ∼ 1.33-1.40) and broad (M_w/M_n ∼ 1.5-2.4) MWDs were obtained respectively with and without nBu₄N⁺Y⁻. However, in toluene, the MWDs of the polystyrenes obtained respectively with and without nBu₄N⁺Y⁻/nR′₄P⁺Br⁻ were moderately narrow (M_w/M_n = 1.33-1.5) and extremely narrow (M_w/M_n = 1.05-1.17). Livingness of this polymerization in CH₂Cl₂ was confirmed via monomer-addition experiment as well as from the study of molecular weights of obtained polystyrenes prepared simply by varying monomer to initiator ratio. A possible mechanistic pathway for this polymerization was suggested based on the results of the ¹H NMR spectroscopic analysis of the model reactions as well as the end group analysis of the obtained polymer.     

[As8W48O184], a new crown-shaped heteropolyanion: Electrochemistry and electrocatalytic properties towards reduction of nitrite

The electrochemical behavior of the new crown-shaped heteropolyanion [As₈W₄₈O₁₈₄]⁴⁰⁻ was investigated. Compared to the analogous complex [P₈W₄₈O₁₈₄]⁴⁰⁻, [As₈W₄₈O₁₈₄]⁴⁰⁻ displayed a close similar behavior. As previously reported for [P₈W₄₈O₁₈₄]⁴⁰⁻, [As₈W₄₈O₁₈₄]⁴⁰⁻ is found to be stable in a large range of pH, roughly from 0 to 8 and found to be slightly more soluble than [P₈W₄₈O₁₈₄]⁴⁰⁻. Comparison between the cyclic voltammetry curves of the two complexes reveals that the potentials of the redox waves of [As₈W₄₈O₁₈₄]⁴⁰⁻ are slightly shifted towards the positive values. Contrary to the high dependence of [P₈W₄₈O₁₈₄]⁴⁰⁻ to buffer capacity of the supporting electrolyte, interestingly, [As₈W₄₈O₁₈₄]⁴⁰⁻ displays less sensitivity. The numerous possibilities for chemical applications opened up by the electrochemistry of this new complex are exemplified here by the good linear relationship between the peak potentials of the redox waves as a function of pH and, by the electrocatalytic reduction of nitrite.     

Effects of Ni2+ concentration on the composition,structure, magnetic properties,and DC-bias superposition characteristics of NiCuZn ferrites

Ni_xCu_0.2Zn_yFe_1.98O₄ (x = 0.16, 0.26, 0.35, 0.43, 0.50; y = 0.8?x) ferrites were prepared via solid-state reaction. The influence of Ni²⁺ concentration on ferrites composition, microstructure, magnetic properties and DC-bias superposition characteristics was studied by XRD, SEM, XPS, and VSM. Then, the effect of magnetic properties on the DC-bias superposition characteristics was analyzed. The results showed that the ferrites sintered at 900 °C for 3 h were all in pure spinel phase with an average grain size of 7.5 μm and a relative density of about 5.15 g cm^?3. With the increase in Ni²⁺ concentration, the saturation magnetization (M_s) and coercivity (H_c) of ferrites increased, but the magnetocrystalline anisotropy constant (K₁) first increased and then decreased. And the M_s, H_c, and K₁ of the specimen with x = 0.43 were 63.62 emu·g^?1, 27.36 Oe, and 1813.17 Oe·emu·g^?1, respectively. In particular, the specimen of x = 0.50 achieved the best DC superposition characteristics, where the H_70% was about 220 A m^?1. The incremental permeability of the specimens decreased rapidly at a bias magnetic field <400 A m^?1. The variation mainly originated from the domain wall displacement, and the rate of decrease was influenced by both M_s and K₁. At a bias magnetic field ≥400 A m^?1, the incremental permeability of the specimens decreased slowly, mainly because the number of domain walls decreased until disappearing, and the specimens tended to become a single domain structure. And the rate of decrease of incremental permeability was mainly affected by K₁.     

Free-radical propagation and termination kinetics of the butyl acrylate dimer studied by pulsed laser polymerization techniques

The propagation and termination rate coefficients for bulk polymerization of the butyl acrylate dimer (BA dimer) are determined by pulsed laser techniques. The rate coefficient for propagation, k_p, is deduced for temperatures from 20 to 90 °C via the pulsed laser polymerization-size exclusion chromatography (PLP-SEC) method at pulse repetition rates between 1 and 10 Hz. The Arrhenius parameters were found to be: E_A(k_p) = (34.2 ± 1.0) kJ mol⁻¹ and A(k_p)/L mol⁻¹ s⁻¹ = (1.08 ± 0.49) × 10⁷ L mol⁻¹ s⁻¹. The termination rate coefficient, k_t, has been measured via SP-PLP-ESR, single pulse-pulsed laser polymerization in conjunction with time-resolved electron spin resonance detection of radical concentration. The resulting Arrhenius parameters as deduced from the temperature range −15 to +30 °C are: E_A(〈k_t〉) = (22.8 ± 3.7) kJ mol⁻¹ and log(A/L mol⁻¹ s⁻¹) = 10.6 ± 1. The chain-length dependence of k_t was studied at 30 °C. For short chains a significant dependence was found which may be represented by an exponent α = 0.79 in the power-law expression k_t(i) = k_t⁰i^−α.     

Long terminal linear alkyl group as internal crystallization accelerating moiety of poly(l-lactide)

Poly(l-lactide) (PLLA) polymers having terminal n-alkyl groups with a wide variety of lengths (C₀–C₂₂) were synthesized by ring-opening polymerization of l-lactide in the presence of coinitiators of l-lactic acid (C₀), 1-hexanol (C₆), 1-dodecanol (C₁₂), and 1-docosanol (C₂₂) and their segmental mobility and non-isothermal and isothermal crystallization behavior were investigated by differential scanning calorimetry (DSC) and wide-angle X-ray diffractometry (WAXD). Glass transition and cold crystallization temperatures of melt-quenched samples during heating decreased with an increase in the length of terminal n-alkyl groups. The enhanced PLLA segmental mobility and hydrophobic interaction-based accelerated PLLA nucleation by the presence of terminal long n-alkyl groups should have caused the accelerated non-isothermal and isothermal crystallization of PLLA segments traced by cold crystallization temperature during heating and by radial growth rate of spherulites, respectively. The crystallization accelerating effect became higher with the length of terminal n-alkyl groups. The effects of the length of terminal n-alkyl group on the crystalline growth mechanism of PLLA at the lowest crystallizable temperature was insignificant, whereas the effects of the length of terminal n-alkyl group on the nucleation mechanism of PLLA chains were significant and insignificant for PLLA having M_n of 6–7 × 10³ of 2 × 10⁴ g mol⁻¹, respectively. WAXD measurements revealed that the transition crystallization temperature at which crystalline modification changes from δ-form to α-form was affected by the length of terminal n-alkyl group for PLLA having M_n of 6–7 × 10³ g mol⁻¹, but was not altered by the length of terminal n-alkyl group for PLLA having M_n of 2 × 10⁴ g mol⁻¹.