NIR-Triggered Generation of Reactive Oxygen Species and Photodynamic Therapy Based on Mesoporous Silica-Coated LiYF4 Upconverting Nanoparticles

To date, the increase in reactive oxygen species (ROS) production for effectual photodynamic therapy (PDT) treatment still remains challenging. In this study, a facile and effective approach is utilized to coat mesoporous silica (mSiO₂) shell on the ligand-free upconversion nanoparticles (UCNPs) based on the LiYF₄ host material. Two kinds of mesoporous silica-coated UCNPs (UCNP@mSiO₂) that display green emission (doped with Ho³⁺) and red emission (doped with Er³⁺), respectively, were successfully synthesized and well characterized. Three photosensitizers (PSs), merocyanine 540 (MC 540), rose bengal (RB), and chlorin e6 (Ce6), with the function of absorption of green or red emission, were selected and loaded into the mSiO₂ shell of both UCNP@mSiO₂ nanomaterials. A comprehensive study for the three UCNP@mSiO₂/PS donor/acceptor pairs was performed to investigate the efficacy of fluorescence resonance energy transfer (FRET), ROS generation, and in vitro PDT using a MCF-7 cell line. ROS generation detection showed that as compared to the oleate-capped and ligand-free UCNP/PS pairs, the UCNP@mSiO₂/PS nanocarrier system demonstrated more pronounced ROS generation due to the UCNP@mSiO₂ nanoparticles in close vicinity to PS molecules and a higher loading capacity of the photosensitizer. As a result, the three LiYF₄ UCNP@mSiO₂/PS nanoplatforms displayed more prominent therapeutic efficacies in PDT by using in vitro cytotoxicity tests.     

A Novel Near-IR Absorbing Ruthenium(II) Complex as Photosensitizer for Photodynamic Therapy and its Cetuximab Bioconjugates

A novel Ru(II) cyclometalated photosensitizer (PS), Ru-NH₂ , for photodynamic therapy (PDT) of formula [Ru(appy)(bphen)₂]PF₆ (where appy=4-amino-2-phenylpyridine and bphen=bathophenanthroline) and its cetuximab (CTX) bioconjugates, Ru-Mal-CTX and Ru-BAA-CTX (where Mal=maleimide and BAA=benzoylacrylic acid) were synthesised and characterised. The photophysical properties of Ru-NH₂ revealed absorption maxima around 580 nm with an absorption up to 725 nm. The generation of singlet oxygen (¹O₂) upon light irradiation was confirmed with a ¹O₂ quantum yield of 0.19 in acetonitrile. Preliminary in vitro experiments revealed the Ru-NH₂ was nontoxic in the dark in CT-26 and SQ20B cell lines but showed outstanding phototoxicity when irradiated, reaching interesting phototoxicity indexes (PI) >370 at 670 nm, and >150 at 740 nm for CT-26 cells and >50 with NIR light in SQ20B cells. The antibody CTX was successfully attached to the complexes in view of the selective delivery of the PS to cancer cells. Up to four ruthenium fragments were anchored to the antibody (Ab), as confirmed by MALDI-TOF mass spectrometry. Nonetheless, the bioconjugates were not as photoactive as the Ru-NH₂ complex.     

Click synthesis of glycosylated porphyrin-cored PAMAM dendrimers with specific recognition and thermosensitivity

Glycoporphyrin dendrimers have received increasing attentions due to their distinct physical and chemistry properties, such as fluorescence and water solubility. They also acted as a promising photodynamic therapy (PDT) sensitizer and used in the study of carbohydrate-protein interaction. In this study, different generations of porphyrin-cored dendrimers consisting of glycosylated siloxane-poly (amido amine) typed dendron (PP-Si-PAMAM-D_m-Lac, m?=?1, 2, and 3), multifunctional specific-targeting sensitizers, had been synthesized via click reaction. The structure of PP-Si-PAMAM-D_m-Lac was characterized by ¹H NMR, GPC, FT-IR, UV-vis and fluorescence analyses. This glycoporphyrin dendrimers, not only obtained high fluorescence quantum yield and singlet oxygen production efficiency, but also showed specific recognition of lectin and remarkable temperature-responsive property (20–80 °C). These properties proved a facile click synthetic strategy of glycosylated siloxane-poly (amido amine) typed dendrimers with multiple functions as a promising tumor-selective photsensitizer (PS) for PDT and also allow applications in highly sensitive fluorescent probes over a larger temperature window.     

Fabrication of alumina based electrically conductive polymer composites

Novel electrically conductive composites were synthesized by incorporating Cu coated alumina (Cu‐Al₂O₃) powder prepared via electroless plating technique as filler (0–21wt %) into polystyrene‐b‐methylmethacrylate (PS‐b‐PMMA) and polystyrene (PS) matrices. XRD analysis depicted maximum Cu crystallite growth (26.116 nm～ plating time 30 min) onto Al₂O₃ along with a significant change in XRD patterns of composites with Cu‐Al₂O₃ inclusion. SEM–EDX analyses exhibited uniform Cu growth onto Al₂O₃ and confirmed presence of Cu, Al, Pd in Cu‐Al₂O₃, and C, O, Al, Cu, and Pd in PS‐b‐PMMA and PS composites. Increasing filler loadings exhibited increased electrical conductivity (5.55 × 10^?5S/cm for PS‐b‐PMMA; 5.0 × 10^?6S/cm for PS) with increased Young's modulus (1122MPa for PS‐b‐PMMA; 1053.9MPa for PS) and tensile strength (27.998MPa for PS‐b‐PMMA; 30.585MPa for PS) and decreased % elongation. TGA demonstrated increased thermal stability and DTG revealed two‐step degradation in composites while DSC depicted pronounced increment in T_g of Cu‐Al₂O₃/PS‐b‐PMMA with increased filler loading. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 42939.     

Synthesis and characterization of polystyrene‐supported glucosamine resin and its adsorption behavior for Au(III)

A novel chelating resin, crosslinking polystyrene‐supported glucosamine (PS‐GA), was prepared and its structure was confirmed by FTIR, elemental analysis, and X‐ray photoelectron spectroscopy. The adsorption properties of PS‐GA for Au(III) were investigated. PS‐GA resin possessed excellent enriching property to Au(III) ions and adsorption proportion E% could reach to about 90 shortly after 3 h. The adsorption dynamics of Au(III) showed that the adsorption was controlled by liquid film diffusion and the apparent activation energy E_a was 12.91 kJ mol^?1. Both Langmuir model and Freundlich model could describe the isothermal process of Au(III), and ΔG, ΔH, ΔS values were calculated. The mechanism of adsorption for Au(III) was confirmed by FTIR, SEM, and XPS. The results showed that redox reaction occurred and both coordination and ion‐exchange existed simultaneously in the adsorption. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 100: 4581–4586, 2006     

Drug Carrier for Photodynamic Cancer Therapy

Photodynamic therapy (PDT) is a non-invasive combinatorial therapeutic modality using light, photosensitizer (PS), and oxygen used for the treatment of cancer and other diseases. When PSs in cells are exposed to specific wavelengths of light, they are transformed from the singlet ground state (S₀) to an excited singlet state (S₁–S_n), followed by intersystem crossing to an excited triplet state (T₁). The energy transferred from T₁ to biological substrates and molecular oxygen, via type I and II reactions, generates reactive oxygen species, (¹O₂, H₂O₂, O₂*, HO*), which causes cellular damage that leads to tumor cell death through necrosis or apoptosis. The solubility, selectivity, and targeting of photosensitizers are important factors that must be considered in PDT. Nano-formulating PSs with organic and inorganic nanoparticles poses as potential strategy to satisfy the requirements of an ideal PDT system. In this review, we summarize several organic and inorganic PS carriers that have been studied to enhance the efficacy of photodynamic therapy against cancer.     

Camphene/polystyrene solutions: A rheological approach for material processing industry

Rheological properties of polymer–camphene solutions are very relevant as they affect their stability, and they have many implications in operation costs. This work elucidates the rheological properties of polystyrene (PS–camphene) solutions with industrial applications. Unfortunately, the assessment of the very low shear viscosities of camphene-based materials (below 0.005 Pa s) is still a challenge with commercial rheometers. Flow curves, stress growth tests, and small amplitude oscillatory shear (SAOS) measurements were carried out as a function of PS concentration (0, 2.5, 5.0, 10, and 20 wt % PS) to understand the rheological behavior of these systems. Results indicate that liquid camphene has a shear-thinning behavior (flow index = 0.99) when the increase of polymer concentration involves changes in the structure of these systems (flow index = 0.10 for 20 wt % PS). An increase in PS concentration leads to a forwarding in the shear-thinning zone, and the Newtonian region (from ∼1 s⁻¹, for 0 wt % PS, to 10⁻³ s⁻¹ for 20 wt % PS). Eventually, these results evidence the high dependence of η_∞ on PS concentration (from ∼1.16 ± 0.01 Pa s, for 0 wt % PS, to 631.5 ± 0.2 Pa s for 20 wt % PS). © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47953.     

Analyses of structurally modified quasi‐solid‐state electrolytes using electrochemical impedance spectroscopy for dye‐sensitized solar cells

Electrochemical properties of structurally modified quasi‐solid‐state electrolytes were examined using porous substrates (PSs). The PS was prepared into two categories by a phase inversion method with a brominated poly(phenylene oxide) (BPPO): the sponge and finger types. Effects of the humidification and cosolvent compositions on the morphology of the PS were analyzed by scanning electron microscopy. In all cases of the PSs, a higher V_OC was observed of about 0.1 V than that of a liquid electrolyte owing to a suppressed back electron charge transfer. In addition, the PS prepared by the polymer solution of 1 : 4 : 1 (BPPO : N‐methyl‐2‐pyrrolidone : butyl alcohol) with the humidification process showed better photovoltaic properties in terms of the current density and conversion efficiency owing to the appropriate combinations of pore size, tortuosity, and interconnectivity. Effects of the pore structures were intensively examined using electrochemical impedance spectroscopy. The impedance results revealed that large pores at the surface layers are advantageous for a lower R_S and R_TiO2. Meanwhile, the straight inner structure is beneficial for the facile I^?/I₃^? diffusion, thus lowering R_Pt. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 39739.     

Phase separation temperatures in the polystyrene—poly(α-methyl styrene)—methylcyclohexane system

The phase separation temperatures (PST) in the ternary system polystyrene (PS) (M_w = 1.75 × 10⁴ g mol⁻¹ — poly(α-methyl styrene) (PαMS) (M_w = 6.0 × 10⁴) — methylcyclohexane (MCH) and the binary systems PS-MCH and PαMS-MCH have been determined by using a He---Ne laser light-scattering apparatus over the total polymer weight fraction (W_{PS + PαMS}) range of 0.018 to 0.80 and various polymer blend ratios. The PST determined at a scattering angle of 0° agreed with those at 90° for the binary systems over polymer concentrations of 0.1 to 0.7 and for the ternary over W_{PS + PαMS} of higher than 0.3. Deviations of the PST determined at an angle of 90° from those at 0° were observed in the ternary system when W_{PS + PαMS} was lower than 0.3. Two phase separation temperatures, at which the intensity scattered from zero angle changed discontinuously, are observed at concentrations lower than W_{PS + PαMS} = 0.042 in the ternary system. The PST in the ternary system decreases monotonically with increasing W_{PS + PαMS} over 0.3 to 0.7. The phase diagram for the PS-PαMS-MCH system at W_{PS + PαMS} = 0.8 is characterized by a maximum PST around − 14°C.     

Biocompatible palm stearin‐based polyesteramide as polymer carrier for solid dispersion

Palm stearin‐based polyesteramide (PSPEA) was synthesized by reacting PS with diethanolamine, followed by azelaic acid at functionality molar ratio (OH: COOH) ranged 1:0.84 to 1:0.95 at 150–190 °C. FTIR, ¹H‐nuclear magnetic resonance, ¹³C‐nuclear magnetic resonance, and gel permeation chromatography were used to elucidate the chemical structure and M_w distribution of the PSPEA. PSPEA 4000 (acid value = 0.61 mg KOH/g sample, hydroxyl value = 51.97 mg KOH/g sample) was used in combination with stearic acid‐based PEA to prepare mefenamic acid (MA) solid dispersion. The solid dispersion demonstrated sixfold and twofold enhancement in T_50% and cumulative drug release as compared to pure MA. The differential scanning calorimetry and scanning electron microscopy analyses revealed solubilization of MA in PEA and transformation of MA into amorphous. In vitro cytotoxicity studies confirmed the safety profile of PSPEA against 3T3 fibroblast cell lines. This work demonstrated that the biocompatible PSPEA possesses surface tension lowering and anticrystallization effects have the potential as polymer carrier for pharmaceutical dosage forms. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45892.     

Synthesis and phase behavior of new cholesteric liquid‐crystalline copolymers containing chiral mesogenic groups derived from menthol derivatives

The synthesis of a new chiral mesogenic monomer ( M₁ ), a nematic monomer ( M₂ ), and a series of side chain cholesteric copolymers ( P₂ – P₆ ) containing the mesogenic menthyl groups is described. The chemical structures of the compounds were confirmed by FTIR and ¹H NMR. The mesomorphic properties and phase behavior were investigated by differential scanning calorimetry, thermogravimetric analysis, and polarizing optical microscopy. M ₁ showed an enantiotropic cholesteric phase, and M₂ revealed a nematic phase. The homopolymers P₁ and P₇ , respectively, displayed a chiral smectic A (S_A) phase and a nematic phase, while the copolymers P₂ – P₆ exhibited the Grandjean texture of the cholesteric phase. T_g, T_i, and ΔT of P₁ – P₇ increased with increasing the concentration of M₂ in the polymers. All of the obtained polymers displayed very good thermal stability and the wide mesophase temperature range. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Conjugated Polymers with Aggregation-Induced Emission Characteristics for Fluorescence Imaging and Photodynamic Therapy

Accurate diagnosis and treatment have been extensively developed in the field of biomedicine, which put forward higher requirements for the development of biomedical materials with high efficiency and selectivity. Among them, conjugated polymers featuring aggregation-induced emission (AIE) characteristics (AIE conjugated polymers) have stood out in recent years owing to their unique properties, such as intense solid emission, high light-harvesting ability, efficient energy transfer, and high ¹O₂ generation ability, which empower them with effective biomedical functions in fluorescence imaging (FLI), photodynamic therapy (PDT), FLI-guided PDT, two-photon excited photodynamic therapy (2PE-PDT), etc. In this review, we highlight recent progress in AIE conjugated polymers and their applications in anticancer and antibacterial areas based on FLI and PDT, and summarize the mechanism of color-tuned fluorescence emission and efficient ¹O₂ generation ability. The challenges and perspectives for the future development of AIE conjugated polymers are also discussed.     

Synthesis,characterization, and kinetic study of functional polystyrenes

In this study, functionalization of polystyrene (PS) (M_n = 2.5 × 10⁵) was carry out with maleic anhydride in the presence of boron trifluoride dietyhletherade (BF₃ OEt₂) as catalyst and then functional PS was subjected to condensation reaction with phenyl hydrazine. The structures of both of them were determined by using FTIR, ¹H‐NMR, elemental analysis, thermogravimetric analysis (TGA) and differential thermal analysis (DTA) techniques. Some physical properties of these two products were investigated and the kinetic parameters of solid state decomposition reactions were determined from TGA curves. The intrinsic viscosity [η] values of modified PS and condensation products (cPs) found to be 1.024 and 0.7036 dL g^?1, respectively. According to TGA, the weight losses of modified PS and cPs were found to be 84.03 and 81.86%, respectively, at 500°C. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci 2007     

Hybridized 4-Trifluoromethyl-(1,2,3-triazol-1-yl)quinoline System: Synthesis,Photophysics, Selective DNA/HSA Bio-interactions and Molecular Docking

The synthesis, structural analysis, and evaluation of the photophysical properties of twelve novel 2-aryl(heteroaryl)-6-(4-alkyl(aryl)-1H-1,2,3-triazol-1-yl)-4-(trifluoromethyl)quinolines ( 6-8 ), where aryl(heteroaryl)=Ph, 4-Me-C₆H₄, 4-F-C₆H₄ and 2- furyl; 4-alkyl(aryl)=−CH₂OH, −(CH₂)₅CH₃ and Ph, are reported. Hybrid scaffolds 6 – 8 were synthesized at 77–95 % yields by regioselective copper-catalysed azide-alkyne cycloaddition (CuAAC) reaction of unpublished 6-azido-4-(trifluoromethyl)quinolines ( 2 ) with selected terminal alkynes ( 3 – 5 ). Azido intermediates 2 were obtained from the reaction of 6-amino-4-(trifluoromethyl)quinolines ( 1 ) and sodium azide at good yields (78–87 %). Compounds 6 – 8 were structurally fully characterized by ¹H−, ¹³C− and ¹⁹F− and ¹H−¹³C 2D-NMR (HSQC, HMBC) spectroscopy, X-ray diffraction (SC-XRD) and HRMS analysis. Moreover, the photophysical properties, DNA- and HSA-binding experiments (bio-interactions), and molecular docking studies for compounds 6 – 8 were performed. These are discussed and compared with similar compounds from recent research.     

Enhancing performance of optical sensor through the introduction of polystyrene and porous structures

Simple and promising approaches for developing high‐performance Fe³⁺ sensors were proposed. Polyvinyl chloride (PVC) membrane containing pyrene as a fluorescent indicator was prepared via solvent‐cast method. Upon immersion into 1.0 mM Fe³⁺ solution, the fluorescence emission of the membrane decreased with the ratio of fluorescence intensities before and after (F₀/F) immersion of 1.25. The sensitivity enhancement was achieved through the introduction of polystyrene (PS) onto PVC and the introduction of porous structures. Polyvinyl chloride‐graft‐polystyrene copolymers (PVC‐g‐PS) were synthesized via Atom Transfer Radical Polymerization using PVC as macroinitiator. The grafting percentages of PS on PVC calculated from Nuclear Magnetic Resonance Spectroscopy were 17 and 41. The membrane prepared from low molecular weight copolymer showed higher sensing ability than that from PVC with the F₀/F value of 1.39. The increase in PS chain length did not significantly affect the fluorescence quenching. A Stern–Volmer quenching relationship was found with K_sv of 3.96 × 10² M^?1. The effect of porous structures on fluorescence quenching was studied by introducing Triton X‐100 as a porogen to PVC/pyrene solution. Attenuated total reflection Fourier transform infrared spectroscopy and Scanning Electron Microscopy analyses confirmed a complete removal of Triton X‐100 after 3 days of immersion in water. The porous membrane demonstrated an enhanced sensing performance with the F₀/F value of 1.46. PVC‐g‐PS/pyrene membrane exhibited highly sensitive and selective responses toward Fe³⁺ over Cu²⁺, Mg²⁺, Co²⁺, Zn²⁺, Ni²⁺, and Ag⁺. In addition, a good reversibility after five cycles of quenching and regeneration was obtained. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 41759.     

In situ compatibilization of polystyrene/polyolefin elastomer blends by the Friedel–Crafts alkylation reaction

Blends of polystyrene (PS) with polyolefin elastomer (POE) were prepared by a reactive extrusion method. In order to increase the compatibility of the two blending components, a Lewis acid catalyst, aluminium chloride (AlCl₃), was adopted to initiate the Friedel–Crafts alkylation reaction. Fourier‐transform infrared (FTIR) spectra of the PS/POE/AlCl₃ blends extracted with butanone verified the graft structure between the PS and POE. Because the in situ generated PS‐graft‐POE copolymers acted as compatibilizers, the mechanical properties of PS/POE blends were greatly improved. For example, after compatibilization, the Charpy impact strength of an 80/20 (wt%) PS/POE blend was increased from 6.29 to 8.50 kJ m^?2. Scanning electron microscopy (SEM) showed that the size of the droplets decreased from 9–10 µm to less than 2 µm with the addition of AlCl₃. Gel permeation chromatography (GPC) showed competition between the grafting reaction and the degradation of blending components in the presence of AlCl₃. Copyright © 2005 Society of Chemical Industry     

Ba0.9Ca0.1TiO3: microwave-assisted hydrothermal synthesis and piezoelectric properties

ABSTRACT

This communication reports the microwave-assisted hydrothermal synthesis of the x?=?0.1 member of the solid solution Ba_1–xCa_xTiO₃ (BCT) materials, its structural and microstructural characterisation and the piezoelectric properties. Using this novel – ‘fast chemistry’ – synthetic procedure, this material can be obtained in much shorter periods of time in comparison with conventional solid-state methodologies: just a few minutes instead of days. Under microwave irradiation in aqueous basic solutions, the material produced is a polycrystalline and nanosized powder which was processed as a ceramic disc in order to measure piezoelectric properties. A maximum d₃₃ value of 118?pC/N is obtained for this sample with a poling electric field of 1.5?KV?mm^?1, a value similar to those reported for conventionally made BCT materials.     

Structural and emission properties of Eu3+‐doped alkaline earth zinc‐phosphate glasses for white LED applications

Quaternary alkaline earth zinc‐phosphate glasses in molar composition (40 ? x)ZnO – 35P₂O₅ – 20RO – 5TiO₂ – xEu₂O₃ (where x=1 and R=Mg, Ca, Sr, and Ba) were prepared by melt quenching technique. These glasses were studied with respect to their thermal, structural, and photoluminescent properties. The maximum value of the glass transition temperature (T_g) was observed for BaO network modifier mixed glass and minimum was observed for MgO network modifier glass. All the glasses were found to be amorphous in nature. The FT‐IR suggested the glasses to be in pyrophosphate structure, which matches with the theoretical estimation of O/P atomic ratio and the maximum depolymerization was observed for glass mixed with BaO network modifier. The intense emission peak was observed at 613 nm (⁵D₀→⁷F₂) under excitation of 392 nm, which matches well with excitation of commercial n‐UV LED chips. The highest emission intensity and quantum efficiency was observed for the glass mixed with BaO network modifier. Based on these results, another set of glass samples was prepared with molar composition (40 ? x)ZnO – 35P₂O₅ – 20BaO – 5TiO₂ – xEu₂O₃ (x=3, 5, 7, and 9) to investigate the optimized emission intensity in these glasses. The glasses exhibited crystalline features along with amorphous nature and a drastic variation in asymmetric ratio at higher concentration (7 and 9 mol%) of Eu₂O₃. The color of emission also shifted from red to reddish orange with increase in the concentration of Eu₂O₃. These glasses are potential candidates to use as a red photoluminsecent component in the field of solid‐state lighting devices.     

Synthesis of polypyrrole nanoparticles in natural rubber–polystyrene blend via emulsion polymerization

Nanoparticles of polypyrrole (PPy) in 40/60 wt % natural rubber (NR)–polystyrene (PS) blends were synthesized by emulsion polymerization using ferric sulfate [Fe₂ (SO₄)₃], sodium dodecyl sulfate (SDS), and n‐amyl alcohol as the oxidant, surfactant, and cosurfactant, respectively. The NR/PS/PPy blends were characterized by Fourier transform infrared spectroscopy (FTIR), elemental analysis, thermogravimetric analysis (TGA), and field emission scanning electron microscopy (FESEM). FESEM micrographs showed that NR/PS/PPy blends were homogeneous, and PPy nanoparticles were well distributed throughout the binary matrix of NR/PS. The size of PPy particles in the blends was in the range of 26–80 nm. The electrical conductivities of the pellets prepared from NR/PS/PPy blends increased as the composition of PPy nanoparticles was increased, which were in the range of 8.9 × 10^?8 – 2.89 × 10^?4 S/cm. Thermal stability of the blends increased as the content of PPy was increased, as shown by TGA thermograms. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012     

Synthesis and properties of polystyrene‐b‐poly(ethylene oxide)‐b‐polystyrene triblock copolymers

A series of well‐defined and property‐controlled polystyrene (PS)‐b‐poly(ethylene oxide) (PEO)‐b‐polystyrene (PS) triblock copolymers were synthesized by atom‐transfer radical polymerization, using 2‐bromo‐propionate‐end‐group PEO 2000 as macroinitiatators. The structure of triblock copolymers was confirmed by ¹H‐NMR and GPC. The relationship between some properties and molecular weight of copolymers was studied. It was found that glass‐transition temperature (T_g) of copolymers gradually rose and crystallinity of copolymers regularly dropped when molecular weight of copolymers increased. The copolymers showed to be amphiphilic. Stable emulsions could form in water layer of copolymer–toluene–water system and the emulsifying abilities of copolymers slightly decreased when molecular weight of copolymers increased. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 727–730, 2006