Aggregation behaviors of amine-oxide gemini surfactants

The micellar aggregation of a series of gemini surfactants [N, N’-dimethyl-N, N’-bis(2-alkylamideethyl)-ethylenediamine oxide (alkyl?=?C₁₁H₂₃, C₁₃H₂₇, C₁₅H₃₁)] in aqueous media has been investigated. The results show that there is an excellent agreement among the critical micelle concentration (CMC) values obtained by surface tension and steady-state fluorescence methods. Because of the occurrence of self-coiling or the formation of pre-micellization, the CMC values, the I₁/I₃ values, and the micelle aggregation numbers (N_agg) at CMC (N_m) increase with the hydrophobic alkyl chain length increasing. Besides, vesicles are observed above the CMC for all these surfactants.     

Thermodynamic and spectroscopic studies on cationic surfactant tetradecyltrimethylammonium bromide in aqueous solution of trisubstituted ionic liquid 1, 2-dimethyl-3-octylimidazolium chloride at different temperatures

In this work, the effects on micellar behavior of long chain cationic surfactant tetradecyltrimethylammonium bromide (TTAB) upon the addition of trisubstituted ionic liquid (IL), 1, 2-dimethyl-3-octylimidazolium chloride [odmim][Cl] at temperatures, 298.15–318.15 K has been studied. Different techniques such as conductance, surface tension, fluorescence and ¹H NMR have been employed to understand the interactional mechanisms. The values of critical micelle concentration (cmc) and various thermodynamic parameters have been calculated from conductivity measurements. The surface parameters like effectiveness of decrease in surface tension (Π_cmc), minimum surface area occupied per surfactant monomer (A_min), maximum surface excess concentration (Γ_max), and adsorption efficiency (pC₂₀) have been evaluated by surface tension measurements. Micellar aggregation number (N_agg) has been determined by quenching of pyrene. Further to understand interactions in post micellar region, ¹H NMR measurements have been performed. It has been observed that the lipophilicity of interacting ion modified the thermodynamic and aggregation properties of TTAB.     

Interactions Between the Cationic Surfactants Bearing Different Polar Head Groups: Interfacial,Conductivity, NMR,and Fluorescence Studies

Interfacial tension (γ), conductivity (κ), nuclear magnetic resonance (NMR), and fluorescence measurements have been carried out to study the mixed interfacial and micellar behavior of cationic surfactants cetyltributylphosphonium bromide (CTBB) and the cetyltrimethylammonium bromide (CTAB). From the γ versus log C _s plots, the values of critical micellar concentration (cmc) and various interfacial parameters were computed. From κ measurements, the equivalent conductivities of the monomers (Λ _mon), the micelles (Λ _mic) states and the degree of counterion dissociation (δ) have been evaluated. The cmc values have been analyzed in the context of the pseudophase separation model and regular solution theory. The interaction parameters, β^m and β^σ, in the mixed micelle as well as in the mixed monolayer, respectively, also have been computed. The self‐diffusion coefficients for the micelles have been evaluated by using NMR spectroscopy. From the fluorescence quenching method, the mean micellar aggregation number (N _agg) of the pure and mixed micelles has been obtained from the slope of the ratio of fluorescence intensities in the absence and in the presence of quencher (ln (I _1,0/I ₁) versus [Q] plots. It was found that the incorporation of CTBB into the mixed micelle decreases the N _agg. The microviscosity of the fluorescence probe Rhodamine (RB) was monitored by using fluorescence polarization measurements. The values of fluorescence anisotropies (r) indicate that the penetration of CTBB monomer into CTAB micelles produced less rigid mixed micelles.     

Monitoring the Discontinuous Dodecamer–Icosamer Transition of a Calix[4]arene-Derived Surfactant by Time-Resolved Small-Angle X-ray Scattering

Calix[4]arene-derived surfactants form monodisperse micelles with a well-defined aggregation number (N_agg) of 4, 6, 8, 12, or 20, corresponding to the Platonic solids. This feature is in strong contrast to conventional micelles. In this study, a transition from a dodecamer (N_agg=12) to an icosamer (N_agg=20) was induced by a rapid increase in the NaCl concentration (C_NaCl) using a stopped-flow device and directly observed by time-resolved small-angle X-ray scattering. The N_agg remained unchanged during the first 60 s after the increase in C_NaCl , and then abruptly increased to 20. This feature resembles phase transitions in supersaturated or supercooled states, or highly cooperative phenomena. We surmise that this finding may be due to the fact that only a few N_agg values are thermodynamically allowed when N_agg is sufficiently small. This is the first observation of such an induction time in micellar aggregation.     

Effects of stereocomplexation on the physicochemical behavior of PLA/PEG block copolymers in aqueous solution

A series of polylactide/poly(ethylene glycol) (PLA/PEG) block copolymers were synthesized by ring‐opening polymerization of L ‐ or D ‐lactide in the presence of mono‐ or di‐hydroxyl PEG. The effects of stereocomplexation on the physicochemical behavior of PLA/PEG copolymers in aqueous solution were investigated by varying the degree of stereocomplexation or PLLA/PEG to PDLA/PEG ratio. In mixture solutions of insoluble and soluble copolymers, stereocomplexation strongly affects the solubility of the copolymers. In mixture solutions of soluble copolymers, both the size and aggregation number (N_agg) of the aggregates vary as a function of the degree of stereocomplexation. It is suggested that the size variation of the aggregates with increasing the degree of stereocomplexation is dependent on N_agg changes which are determined by two effects: the self‐adjusting of the aggregates so as to minimize the free energy and thus to increase the N_agg, and the kinetics of aggregation which tend to form more aggregates and thus to decrease the N_agg. Combination of the two opposite effects well explains the diverse variations of N_agg and size of the aggregates as a function of the degree of stereocomplexation. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012     

Mixed micelle behavior of poly(ethylene glycol) alkyl ethers with series of monomeric cationic, phosphonium cationic, and zwitterionic surfactant

The steady state fluorescence measurements have been carried out for the binary mixtures of poly(ethylene glycol) alkyl ethers (C _i E _j ) with series of monomeric cationic (MC), zwitterionic (ZI), and phosphonium cationic (PC) surfactants over the whole mole fraction range by using pyrene as fluorescence probe. The cmc values for all the binary mixtures, thus, determined have been further evaluated by using the regular solution theory. The various micellar parameters such as regular solution interaction parameter (β), micropolarity (I ₁/I ₃), and mean micelle aggregation number (N _agg) have been determined. A strong influence of hydrophobicity of both nonionic as well as cosurfactant (CS) components has been observed on the nature of mixed micelles. The presence of bulky head groups of PC surfactants significantly contributes towards the unfavorable mixing.     

Mesoscopic simulation of alkylimidazoline self-aggregation in aqueous solution

A dissipative particle-dynamics method was used to simulate the self-aggregation behavior of 15 alkylimidazoline surfactants of different structures. The effects of concentration and structure of hydrophilic and lipophilic groups of the alkylimidazolines on the configuration and aggregation number (N_agg) of the micelles were also explored. Results show that the concentration of the alkylimidazoline has a significant influence on the configuration of the micelles generated. More specifically, alkylimidazolines of different concentrations are found to generate different structures (spherical, rod-shaped, layered, and interlaced) in aqueous solution. At low (1–10?wt%) and medium (40?wt%) concentrations, the micelles generated in aqueous solution are spherical and rod-shaped, respectively. At higher concentrations (80?wt%), the micelles generated present interlaced shapes with rod-shaped and layered micelles when the length of the lipophilic chain is greater than C₁₃ or the hydrophilic group is H_c. N_agg is strongly dependent on alkylimidazoline concentration and increases as concentration increases. N_agg is also greatly dependent on the structure of the hydrophilic and lipophilic groups present: it increases as the chain length of the lipophilic group increases but decreases as that of the hydrophilic group increases.     

Interfacial and aggregation properties of aqueous sodium <Emphasis Type="Italic">N</Emphasis>-dodecanoylsarcosinate solutions at different pH

The pH dependence of an anionic surfactant, sodium N-dodecanoylsarcosinate (SLAS), has been studied by measuring interfacial tension, fluorescence, dynamic light scattering, etc., in aqueous solutions with phosphate and borate buffers. The interfacial tension (γ) of SLAS decreases remarkably with a pH decrease and is constant at pH > 7.3. The observed values for the critical micelle concentration (cmc) and the surfactant concentration at which its γ value is reduced by 20 mN/m from that of pure water (C ₂₀) decrease with a pH decrease, while those also become constant at pH > 6.5 and >7.3, respectively. On the other hand, the interfacial excess of SLAS increases at pH < 7.3. These interfacial behaviors have been further investigated by the addition of Tl⁺ which replaces Na⁺ of SLAS. The observed γ values of LAS⁻ with the different counter cations are in the order of H⁺ < Tl⁺ < Na⁺. In order to reveal aggregation properties of SLAS, the aggregation number (N _agg), the micropolarity, the hydrodynamic radius (R _h) of micelle, and the fluorescence anisotropy of Rhodamine B (r) have been evaluated at various pHs. The N _agg value shows a decreasing tendency with a pH increase. The I ₁/I ₃ ratio and the R _h values do not strongly depend on pH. The r value decreases until pH 7 and remains constant at pH > 7.0. These interfacial and micelle properties have been discussed in detail considering the electrostatic interaction and the molecular structures of the hydrophilic headgroup.     

Studying Effect of Typical Nonplanar Cyclic Alcohols (n = 5‐7) on Micellization of Sodium Dodecyl Sulfate (SDS) in Aqueous Solution and Locating Their Solubilization Site in SDS Micelles

Cyclic alcohols (n = 5‐7) are compounds of distinctive nonplanar structure. Effect of the alcohols on micellization of sodium dodecyl sulfate (SDS) in aqueous solution are examined by determining the critical micelle concentration (CMC) by conductometry and the micelle aggregation numbers (N_agg) by fluorometry, respectively. In general, the CMC of SDS decreases with increase in volume of a cyclic alcohol in water and increases further after attaining a minimum value. The N_agg of SDS varies little with small addition of a cyclic alcohol, but decreases when added in sufficient volume. Both the changes of the CMC and N_agg with carbon number in the ring of the alcohols occur irregularly due to their steric reasons and nonplanar nature. The irregularity makes a difference between the cyclic alcohols and their chain counterparts. Based on ¹H NMR chemical shift measurements, the cyclic alcohols are found to be solubilized in the palisade layer in SDS micelles.     

Self-Aggregation of Cationic Dimeric and Anionic Monomeric Surfactants with Nonionic Surfactant in Aqueous Medium

Spectrofluorometric measurements have been used to elaborate the self-aggregation of mixture of anioinic, sodium dodecylbenzenesulfonate (SDBS), and cationic gemini, alkanediyl-α, ω-bis (tetradecyldimethylammonium bromide) (14-4-14) with nonionic surfactant, polyoxyethylene 10 cetyl ether (Brij-56). The critical micelle concentration (cmc) of the binary mixtures has been investigated. Application of the regular solution theory (RST) to the experimental data yield the interaction parameter at mixed micelles (β), indicate an attractive interaction and reflect the synergistic behavior in both Brij-56/SDBS and Brij-56/14-4-14 systems. The micelle aggregation number (N _agg) was measured using a steady state fluorescence quenching method. The N _agg values of the mixed surfactant system were larger than those of pure components. The micropolarity of various combinations and the binding constants (K _sv) were determined from the ratio of intensity of peaks (I ₁/I ₃) of pyrene fluorescence emission spectrum and its quenching, respectively.     

Influence of Surfactant and Charged Monomer Concentrations on Micro-Block Length of Associative Polymers by Micellar Polymerization

In the micellar polymerization to prepare associative polyelectrolyte, the influence of solution environment on hydrophobical micro-block length has been investigated. The results revealed that the aggregation number (N_agg) of surfactant micelles and micro-block length (N_H) of polymers closely related to electrolyte concentration in polymerization solution, and all of the surfactant and charged monomer concentration can change the free counterion concentration (C_aq) to affect N_agg and N_H. Therefore, the N_H with traditional calculation method which N_agg is looked as constant value was not accurate enough. Subsequently, we studied the attribution of N_H to rheological properties. The results indicated that the micro-block length can increase obviously the reversible network strength in solution to make a few contribution of thickening properties of associative polymer.     

Synthesis and Micellar Behaviors of an Anionic Polymerizable Surfactant

A novel anionic polymerizable surfactant sodium (5‐acryloyl‐2‐(dodecyloxy)phenyl) methane sulfonate has been synthesized from phenol, acrylic acid and bromododecane by esterification, Frise rearrangement, sulfomethylation reaction and Williamson etherification. The parameters of the micellar behaviors are as follows: The CMC was 150 ppm at 40 °C; The surface absorption amounts Γ_m was 3.208 × 10^?6 mol m^?2; The molecular areas A_m was 0.550 × 10^?18m² at the interface of air‐water respectively; The aggregation number (N_agg) at C = CMC of this surfactant was 12.     

End‐functionalization of polystyrene by malto‐oligosaccharide generating aggregation‐tunable polymeric reverse micelle

This article describes that glucose, maltose, maltotriose, maltotetraose, maltopentaose, and maltohexaose ( a , b , c , d , e , and f , respectively) were introduced into the initiating chain‐end of polystyrene (PSt) through the 2,2,6,6‐tetramethylpiperidine‐1‐oxyl (TEMPO)‐mediated radical polymerization. A series of glycoconjuaged TEMPO‐adducts, 1a–f , was synthesized and used as the initiators for the polymerization of styrene (St) for 6 h at 120 °C to afford the end‐functionalized PSt's with the acetyl saccharides, 2a–f , in the yields of 37–43%. For 2a–f obtained by the polymerizations using the [St]/[ 1 ] of 125, 250, and 500, the number‐average molecular weights determined by size exclusion chromatography (SEC), M_n,SEC's, were 4800–6300, 8800–10,600, and 18,400–25,200, respectively, which fairly agreed with the predicted values. The end‐functionalized PSt's with saccharides, 3a–f , which were obtained from the deacetylation of 2a–f using sodium methoxide in dry THF, formed the polymeric reverse micelles consisting of a saccharide‐core and a PSt‐shell in chloroform and toluene. The static laser light scattering (SLS) measurements provided the average molar mass of the aggregates in toluene, M_w,SLS's, which ranged from 7.50 × 10⁴ to 1.77 × 10⁵ for 3a , from 1.90 × 10⁵ to 4.93 × 10⁵ for 3b , from 4.41 × 10⁵ to 7.21 × 10⁵ for 3c , from 5.85 × 10⁵ to 8.51 × 10⁵ for 3d , from 7.55 × 10⁵ to 8.53 × 10⁵ for 3e , and from 8.54 × 10⁵ to 9.26 × 10⁵ for 3f . The aggregation numbers, N_agg's, which were calculated from the M_w,SLS's, were from 7 to 24 for 3a , from 20 to 37 for 3b , from 34 to 89 for 3c , from 39 to 116 for 3d , from 41 to 145 for 3e , and from 31 to 146 for 3f . It was confirmed that the aggregation property, such as the M_w,SLS or N_agg values, was strongly related to the polymerization degrees of St (DP's) or the number of the glucose residues (n's) for 3a–f . © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 4864–4879, 2006     

Unlike surfactant–polymer interactions of sodium dodecyl sulfate and sodium dodecylbenzene sulfonate with water-soluble polymers

Single and mixed micelle formation by sodium dodecyl sulfate (SDS) and sodium dodecylbenzene sulfonate (SDBS) and their mixtures in pure water and in the presence of water-soluble polymers such as Synperonic 85 (triblock polymer, TBP), hydroxypropylcellulose (HPC), and carboxymethylcellulose sodium salt (CMC) were studied with the help of conductivity, pyrene fluorescence, cyclic voltammetry, and viscosity measurements. Conductivity measurements showed a single aggregation process for pure surfactants and their mixtures both in pure water as well as in the presence of water-soluble polymers. Triple breaks corresponding to two aggregation processes for SDS, SDBS, and their mixture in the presence of TBP were observed from fluorescence measurements. The first one demonstrated the critical aggregation process due to the adsorption of surfactant monomers on TBP macromolecule. The second one was attributed to the participation of surfactant–polymer aggregates formed at the first one, in the micelle formation process. The aggregation number ( N _agg) of single and mixed micelles and diffusion coefficient ( D) of electroactive probe were computed from the fluorescence and cyclic voltammetry measurements, respectively. Both parameters, along with the viscosity results, indicated stronger SDS–polymer interactions in comparison to SDBS–polymer interactions. Mixed surfactant–polymer interactions showed compensating effects of both pure surfactants. The nature of mixed micelles was found to be ideal in all cases, as evaluated by applying the regular solution and Motomura's approximations.     

Aggregation behavior and intermicellar interactions of cationic Gemini surfactants: Effects of alkyl chain,spacer lengths and temperature

The aggregation behavior of the cationic Gemini surfactants C_mH_2m+1N(CH₃)₂(CH₂)_S (CH₃)₂ N C_mH_2m+1,2Br^? with m = 12, 14 and s = 2, 4 were studied by performing surface tension, electrical conductivity, pulsed field gradient nuclear magnetic resonance (PFG-NMR), and cyclic voltammetry (CV) measurements over the temperature range 298 K to 323 K. The critical micelle concentration (CMC), surface excess (Г_max), mean molecular surface area (A_min), degree of counter ion dissociation (α), and the thermodynamic parameters of micellization were determined from the surface tension and conductance data. An enthalpy–entropy compensation effect was observed and all the plots of enthalpy–entropy compensation exhibit excellent linearity. The micellar self-diffusion coefficients (D_m) and intermicellar interaction parameters (k_d) were obtained from the PFG-NMR and CV measurements. These results are discussed in terms of the intermicellar interactions, the effects of the chain and spacer lengths on the micellar surface charge density, and the phase transition between spherical and rod geometries. The intermicellar interaction parameters were found to decrease slightly with increasing temperature for 14–4–14, which suggests that the micellar surface charge density decreases with increasing temperature. The mean values of the hydrodynamic radius, R_h, and the aggregation number, N_agg, of the Gemini surfactants’ m–4–m micelles were calculated from the micellar self-diffusion coefficient. Moreover, the N_agg values were calculated theoretically. The experimental values of N_agg increase with increases in the chain length and are in good agreement with both previous results and our theoretical results.     

Monitoring the Discontinuous Dodecamer–Icosamer Transition of a Calix[4]arene‐Derived Surfactant by Time‐Resolved Small‐Angle X‐ray Scattering

Calix[4]arene‐derived surfactants form monodisperse micelles with a well‐defined aggregation number (N _agg) of 4, 6, 8, 12, or 20, corresponding to the Platonic solids. This feature is in strong contrast to conventional micelles. In this study, a transition from a dodecamer (N _agg=12) to an icosamer (N _agg=20) was induced by a rapid increase in the NaCl concentration (C _NaCl) using a stopped‐flow device and directly observed by time‐resolved small‐angle X‐ray scattering. The N _agg remained unchanged during the first 60 s after the increase in C _NaCl , and then abruptly increased to 20. This feature resembles phase transitions in supersaturated or supercooled states, or highly cooperative phenomena. We surmise that this finding may be due to the fact that only a few N _agg values are thermodynamically allowed when N _agg is sufficiently small. This is the first observation of such an induction time in micellar aggregation.     

Synthesis of maltopentaose‐conjugated surface‐active styrenic monomers and their micellar homopolymerization in water

Maltopentaose (Mal₅)‐conjugated surface‐active styrenic monomers 1a , 1b , and 1c are described, which contain hydrophobic spacers, such as C1, C5, and C7 alkylene chains, respectively. The glycomonomers 1a‐c were synthesized by the direct β‐N‐glycosyl reaction of styrene derivatives with aminoalkyl groups 4a‐c onto Mal₅ in dry methanol, followed by the N‐acetylation with acetic anhydride. The self‐assembling properties for the aqueous solutions of 1a‐c were characterized by surface tension measurements and light scattering experiments, providing the physicochemical parameters for the formed 1a‐c micelles including the critical micelle concentration, apparent hydrodynamic radius (R_h,app), and weight average aggregation number (N_agg). The transmission electron microscope observations revealed the most important result in this study that 1a produced loose spherical micelles with the number average diameter (d_n) of 26 nm, while both 1b and 1c formed worm‐like micelles with the polymerizable core and the Mal₅ shell, whose number average contour lengths (l_ns) were 130 nm and 68 nm, respectively. The radical homopolymerizations of 1a‐c in water provided a substantial result in this study that 1b and 1c , that is, the glycomonomers forming the worm‐like micelles, showed a very high homopolymerizability in water. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1671–1679     

Interfacial and Thermodynamic Properties of Anionic‐Nonionic Mixed Surfactant System: Influence of Hydrophobic Chain Length of the Nonionic Surfactant

The influence of hydrophobic chain length in nonionic surfactants on interfacial and thermodynamics properties of a binary anionic‐nonionic mixed surfactant was investigated. In this study, nonionic surfactants lauric‐monoethanolamide (C₁₂ MEA) and myrisitic‐monoethanolamide (C₁₄ MEA) were mixed with an anionic surfactant, α‐olefin sulfonate (AOS). The critical micelle concentration (cmc), maximum surface excess (Γ_max), and minimum area per molecule (A_min) were obtained from surface tension isotherms at various temperatures. The thermodynamic parameters of micellization and adsorption were also computed. Micellar aggregation number (N_agg), micropolarity, and binding constant (K_sv) of pure and mixed surfactant system was calculated by fluorescence measurements. Rubingh's method was applied to calculate interaction parameters for the mixed surfactant systems.     

Synthesis of nickel sulfide and nickel–iron sulfide nanoparticles from nickel dithiocarbamate complexes and their photocatalytic activities

[ Ni(dtc)₂] (dtc = N-(pyrrole-2-ylmethyl)-N-thiophenemethyldithiocarbamate ( 1 ), N-methylferrocenyl-N-(2-phenylethyl)dithiocarbamate ( 2 ), N-furfuryl-N-methylferrocenyldithiocarbamate ( 3 ), and (N-[pyrrole-2-ylmethyl]-N-thiophenemethyldithiocarbamato-S,S′)(thiocyanato-N)(triphenylphosphine)nickel(II) ( 4 ) complexes were prepared and characterized by elemental analysis, infrared, ultraviolet–visible, and nuclear magnetic resonance (¹H and ¹³C) spectroscopies. The data were consistent with the formation of square planar nickel(II) complexes, which was confirmed by single-crystal X-ray diffraction studies on 2 and 4 . Fe···Fe interactions exhibited by complex 2 led to supramolecular aggregation. The structure of 4 reveals intermolecular and intramolecular C-H···Ni anagostic interactions. The anion-sensing properties of 2 were studied with halide ions by cyclic voltammetry. It was observed that 2 acts as sensor for bromide. Complexes 1 , 2 , and 3 , were utilized to prepare nickel sulfide, nickel–iron sulfide-1, and nickel–iron sulfide-2, respectively. The composition, structure, morphology, and optical properties of nickel sulfide and nickel–iron sulfides were examined using powder X-ray diffraction, transmission electron microscopy, energy-dispersive X-ray spectroscopy, ultraviolet–visible, fluorescence, and infrared spectroscopy. Powder X-ray diffraction patterns of nickel sulfide, nickel–iron sulfide-1, and nickel–iron sulfide-2 indicate the formation of orthorhombic Ni₉S₈, cubic NiFeS₂, and cubic Ni₂FeS₄, respectively. The photocatalytic activities of as-prepared nickel sulfide and nickel–iron sulfide-1 nanoparticles were investigated for photodegradation of methylene blue and rhodamine-B under ultraviolet irradiation. Nickel–iron sulfide-1 nanoparticles show slightly higher photodegradation efficiency compared with the nickel sulfide nanoparticles.     

Quantification of ATRP initiator density on polymer latex particles by fluorescence labeling technique using copper‐catalyzed azide‐alkyne cycloaddition

We developed a novel fluorescence labeling technique for quantification of surface densities of atom transfer radical polymerization (ATRP) initiators on polymer particles. The cationic P(St‐CPEM‐C₄DMAEMA) and anionic P(St‐CPEM) polymer latex particles carrying ATRP‐initiating chlorine groups were prepared by emulsifier‐free emulsion polymerization of styrene (St), 2‐(2‐chloropropionyloxy)ethyl methacrylate (CPEM), and N‐n‐butyl‐N,N‐dimethyl‐N‐(2‐methacryloyloxy)ethylammonium bromide (C₄DMAEMA). ATRP initiators on the surface of polymer particles were converted into azide groups by sodium azide, followed by fluorescent labeling with 5‐(N,N‐dimethylamino)‐N′‐(prop‐2‐yn‐1‐yl)naphthalene‐1‐sulfonamide (Dansyl‐alkyne) by copper‐catalyzed azide‐alkyne cycloaddition (CuAAC). The reaction time required for both azidation of ATRP‐initiating groups and successive fluorescence labeling of azide groups with Dansyl‐alkyne by CuAAC were investigated in detail by FTIR and fluorescence spectral measurement, respectively. The ATRP initiator densities on the cationic P(St‐CPEM‐C₄DMAEMA) and anionic P(St‐CPEM) particle surfaces were estimated to be 0.21 and 0.15 molecules nm^?2, respectively, which gave close agreement with values previously determined by a conductometric titration method. The fluorescence labeling through click chemistry proposed herein is a versatile technique to quantify the surface ATRP initiator density both on anionic and cationic polymer particles. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 4042–4051