Macroinitiator For Atom Transfer Radical Polymerization Research Articles

Synthesis of amphiphilic ABA triblock copolymer bearing PIB and perfluorocyclobutyl aryl ether-containing segments via sequential living carbocationic polymerization and ATRP

A series of amphiphilic ABA triblock copolymers containing polyisobutylene (PIB) and poly(p-(2-(4-biphenyl)perfluorocyclobutoxy)phenyl methacrylate) (PBPFCBPMA) segments was synthesized via sequential living carbocationic polymerization and atom transfer radical polymerization (ATRP). Living carbocationic polymerization of isobutylene was initially performed at -78 degrees C in n-hexane-CH3Cl followed by end-capping with 1,3-butadiene to provide a well-defined diallyl-Cl-terminated PIB with a narrow molecular weight distribution (M-w/M-n = 1.26). The PIB functionalized at both ends was further transformed into Br-PIB-Br, an ATRP macroinitiator bearing one ATRP initiating group at each end. The target triblock copolymers of PBPFCBPMA-b-PIB-b-PBPFCBPMA with a relatively narrow molecular weight distribution (M-w/M-n <= 1.42) were obtained via ATRP of BPFCBPMA at 70 degrees C in tetrahydrofuran initiated by Br-PIB-Br. The self-assembly behavior of these triblock copolymers in n-hexane, acetone, and 1,1,1-trifluoroacetone was investigated by transmission electron microscopy. It was found that large spherical compound micelles with PIB blocks as coronas were formed in n-hexane, whereas large compound micelles with fluorine-containing PBPFCBPMA blocks as coronas were formed in acetone and 1,1,1-trifluoroacetone.

Poly(ε‐caprolactone)‐graft‐poly(N‐isopropylacrylamide) amphiphilic copolymers prepared by a combination of ring‐opening polymerization and atom transfer radical polymerization: Synthesis, self‐assembly, and thermoresponsive property

ABSTRACTThermoresponsive graft copolymers of ε‐caprolactone and N‐isopropylacrylamide were synthesized by a combination of ring‐opening polymerization and the sequential atom transfer radical polymerization (ATRP). The copolymer composition, chemical structure, and the self‐assembled structure were characterized. The graft length and density of the copolymers were well controlled by varying the feed ratio of monomer to initiator and the fraction of chlorides along PCL backbone, which is acting as the macroinitiator for ATRP. In aqueous solution, PCL‐g‐PNIPAAm can assemble into the spherical micelles which comprise of the biodegradable hydrophobic PCL core and thermoresponsive hydrophilic PNIPAAm corona. The critical micelle concentrations of PCL‐g‐PNIPAAm were determined under the range of 6.4–23.4 mg/L, which increases with the PNIPAAm content increasing. The mean hydrodynamic diameters of PCL‐g‐PNIPAAm micelles depend strongly on the graft length and density of the PNIPAAm segment, allowing to tune the particle size within a wide range. Additionally, the PCL‐g‐PNIPAAm micelles exhibit thermosensitive properties and aggregate when the temperature is above the lower critical solution temperature. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014, 131, 41115.

Effect of atom transfer radical polymerization macroinitiator on properties of poly(meth)acrylate-based pentablock type of thermoplastic elastomers

We report well controlled synthesis of novel tri-component [polyisobutylene (PIB), poly(n-butyl acrylate) (PnBA) and poly(methyl methacrylate) (PMMA)] pentablock copolymers (PMMA-b-PnBA-b-PIB-b-PnBA-b-PMMA) by Atom Transfer Radical Polymerization (ATRP) using PIB as a macroinitiator. The surface properties (hydrophobicity, in vitro oxidative stability and cellular interaction) and the bulk properties (phase separation and mechanical properties) of the PIB-containing pentablock copolymers were compared with PMMA-b-PnBA-b-PDMS-b-PnBA-b-PMMA (where PDMS = polydimethylsiloxane) and conventional PMMA-b-PnBA-b-PMMA copolymers synthesized by PDMS and PnBA macroinitiators respectively. It is revealed that type of ATRP macroinitiator (with low glass transition temperature) influences the properties of resultant pentablock copolymers in terms of phase separation, mechanical properties in vitro oxidative stability, cytocompatibility and cell proliferation. Pentablock copolymers synthesized by PIB macroinitiator exhibited superior overall properties compared to pentablock copolymers synthesized by PDMS macroinitiator and neat triblock copolymer synthesized by PnBA macroinitiator. Among the copolymers tested, one with composition PIB:PnBA:PMMA = 10:64:26 (w/w) exhibited best mechanical property, oxidative stability and cytocompatibility. The newly designed PIB-containing pentablock copolymer may be useful where softness, flexibility, processability and biostability/cytocompatibility are desired.

Synthesis, Characterization, and Aqueous Lubricating Properties of Amphiphilic Graft Copolymers Comprising 2-Methoxyethyl Acrylate

Amphiphilic anionic and cationic graft copolymers possessing poly(2-hydroxyethyl methacrylate) (PHEMA) backbone and poly(methacrylic acid), poly(2-methoxyethyl acrylate-co-methacrylic acid), and poly(2-methoxyethyl acrylate-co-2-(dimethylamino)ethyl methacrylate) grafts are constructed by merging reversible addition–fragmentation chain transfer (RAFT) polymerization, copper-mediated atom transfer radical polymerization (ATRP), and a selective deprotection reaction. Initially, multifunctional ATRP macroinitiators based on PHEMA backbone are prepared by RAFT polymerization. Then ATRP of the corresponding monomers followed by deblocking reaction leads to well-defined amphiphiles with narrow molecular weight distributions (PDI ≤ 1.29) and varying content of methacrylic acid. The graft copolymers showed effective surface adsorption and lubrication for self-mated poly(dimethylsiloxane) (PDMS) contacts in physiological salt concentration. This is indebted from “dilution” of the charges along the grafted chains by balancing neutral/charged repeating units to minimize the accumulated charge repulsion on neutral surface. Improved lubricating properties of the graft copolymers compared to the block copolymer counterparts further support superior stability of graft copolymers on surfaces.

Sub-5 nm Domains in Ordered Poly(cyclohexylethylene)-block-poly(methyl methacrylate) Block Polymers for Lithography

A series of poly(cyclohexylethylene)-block-poly(methyl methacrylate) (PCHE–PMMA) diblock copolymers with varying molar mass (4.9 kg/mol ≤ Mn ≤ 30.6 kg/mol) and narrow molar mass distribution were synthesized through a combination of anionic and atom transfer radical polymerization (ATRP) techniques. Heterogeneous catalytic hydrogenation of α-(hydroxy)polystyrene (PS-OH) yielded α-(hydroxy)poly(cyclohexylethylene) (PCHE-OH) with little loss of hydroxyl functionality. PCHE-OH was reacted with α-bromoisobutyryl bromide (BiBB) to produce an ATRP macroinitiator used for the polymerization of methyl methacrylate. PCHE–PMMA is a glassy, thermally stable material with a large effective segment–segment interaction parameter, χeff = (144.4 ± 6.2)/T – (0.162 ± 0.013), determined by mean-field analysis of order-to-disorder transition temperatures (TODT) measured by dynamic mechanical analysis and differential scanning calorimetry. Ordered lamellar domain pitches (9 ≤ D ≤ 33 nm) were identified by small-angle X-ray sc...

Synthesis and characterization of novel polysiloxane based ABA-type triblock copolymers using ATRP

Abstract Novel polysiloxane based ABA-type triblock copolymers having a secondary amine at the junction point were synthesized using a combination of ring opening equilibration polymerization (ROEP), Michael addition and atom transfer radical polymerization (ATRP). Polysiloxane based bifunctional ATRP macroinitiators were synthesized and subsequently used for controlled radical polymerization of t-butyl acrylate (t-BA) and sulfobetaine methacrylate (SBMA). Gel permeation chromatography (GPC) analysis of the triblocks based on t-BA showed high chain end functionality, due to the disappearance of peaks related to the macroinitiator. ROEP can be used to control the block length of the polysiloxane while ATRP can be used to control the chain length of the outer blocks, making the ABA- type triblock a unique material with secondary amine functionality which can be used for further reaction.

Synthesis and properties of novel biomimetic and thermo-responsive dextran-based biohybrids

A new class of biodegradable, biomimetic and thermo-responsive dextran/synthetic glycopolymer biohybrids (dextran-graft-poly(lactobionamidoethyl methacrylate)-block-poly(di(ethylene glycol) methyl ether methacrylate), dextran-g-(PLAMA-b-PDEGMA)), was synthesized by the direct atom transfer radical polymerization (ATRP) of unprotected lactobionamidoethyl methacrylate (LAMA) glycomonomer and di(ethylene glycol) methyl ether methacrylate (DEGMA) monomer. The dextran macroinitiator for ATRP was prepared by partial esterification of the hydroxyl groups of the polysaccharide with 2-bromo-2-methylpropionic acid (BrMPA). The biohybrids containing PDEGMA segments exhibited a lower critical solution temperature (LCST) behavior, which changed from unimers to aggregates in solutions. Moreover, it was demonstrated that these biohybrids had specific biomolecular recognition with ricinus communis agglutinin 120 (RCA120) in comparison with bovine serum albumin (BSA). Furthermore, these biohybrids showed good biocompatibility in the cytotoxicity assays. This hopefully provides a platform for targeted drug delivery and studying the biomolecular recognition between sugar and lectin.

Synthesis and characterization of novel polysiloxane based ABA-type triblock copolymers using ATRP

Novel polysiloxane based ABA-type triblock copolymers having a secondary amine at the junction point were synthesized using a combination of ring opening equilibration polymerization (ROEP), Michael addition and atom transfer radical polymerization (ATRP). Polysiloxane based bifunctional ATRP macroinitiators were synthesized and subsequently used for controlled radical polymerization of t-butyl acrylate (t-BA) and sulfobetaine methacrylate (SBMA). Gel permeation chromatography (GPC) analysis of the triblocks based on t-BA showed high chain end functionality, due to the disappearance of peaks related to the macroinitiator. ROEP can be used to control the block length of the polysiloxane while ATRP can be used to control the chain length of the outer blocks, making the ABA- type triblock a unique material with secondary amine functionality which can be used for further reaction.

Novel supramolecular block copolymer containing organic–inorganic pentablock copolymer by ATRP of styrene and vinyl acetate using polydimethylsiloxane/cyclodextrin inclusion complexes as macroinitiator

Organic–inorganic pentablock copolymers have been synthesized via atom transfer radical polymerization (ATRP) of styrene (St) and vinyl acetate (VAc) monomers at 60 °C using CuCl/N,N,N′,N″,N″-pentamethyldiethylenetriamine as a catalyst system initiated from boromoalkyl-terminated poly(dimethylsiloxane) (PDMS)/cyclodextrins macroinitiator (Br-PDMS/γ-CD). Br-PDMS-Br was reacted with γ-CD in different conditions with inclusion complexes being characterized through hydrogen nuclear magnetic resonance (1H NMR) and differential scanning calorimetry (DSC). Resulting Br-PDMS-Br/γ-CD inclusion complexes were taken as macroinitiators for ATRP of St and VAc. Well-defined poly(styrene)-b-poly(vinyl acetate)-b-poly(dimethylsiloxane/γ-cyclodextrin)-b-poly(vinyl acetate)-b-poly(styrene) (PSt-b-PVAc-b-PDMS/γ-CD-b-PVAc-b-PSt) pentablock copolymer was characterized by 1H NMR, gel permeation chromatograph (GPC) and DSC. There was a good agreement between the number-average molecular weight calculated from 1H NMR spectra and that of theoretically calculated. Pentablock copolymers consisting of Br-PDMS-Br/γ-CD inclusion complex as central blocks (inorganic block) and PVAc and PSt as terminal blocks were synthesized by this technique. PSt-b-PVAc-b-PDMS/γ-CD-b-PVAc-b-PSt pentablock copolymer can undergo a temperature-induced reversible transition upon heating of the copolymer complex from white complex at 22 °C to green complex in 55 °C which characterized with XRD and 1H NMR. XRD showed a change in crystallinity percent of St peak with changing the temperature which calculated by Origin75 software.

Brush-like amphiphilic copolymers based on polylactide and poly(ethylene glycol): Synthesis, self-assembly and evaluation as drug carrier

A series of novel amphiphilic poly(poly(ethylene glycol) methacrylate)-block-poly(l-lactide)-block-poly(poly(ethylene glycol) methacrylate) (P(PEGMA)-b-PLLA-b-P(PEGMA)) copolymers were synthesized by combination of ring-opening polymerization (ROP) and atom transfer radical polymerization (ATRP). First, two α,ω-telechelic PLLA ATRP macroinitiators were prepared in two steps via ROP of l-lactide using a difunctional initiator, and subsequent reaction of the hydroxyl end groups with 2-bromoisobutyryl bromide. Then, the ATRP of poly(ethylene glycol) methacrylate was carried out using PLLA macroinitiators. The resulting brush-like triblock copolymers were characterized by 1H NMR, size exclusion chromatography and DOSY NMR. The aggregation behavior of the copolymers in aqueous medium was investigated by fluorescence spectroscopy, dynamic light scattering (DLS), and transmission electron microscopy (TEM). The critical aggregation concentration was in the range of 0.08–0.12 g L−1. The diameter of the nanoparticles (NPs), determined by DLS, was around 100 nm. TEM images showed that these nano-sized objects were spherical in shape. Preliminary studies with a hydrophobic model drug, namely clofazimine, exhibited that such NPs could be potential candidates for drug delivery carrier.

Synthesis of Poly (methyl methacrylate)/Zinc Oxide Nanocomposite with Core-Shell Morphology by Atom Transfer Radical Polymerization

A method to prepare zinc oxide (ZnO) nanoparticles with a covalently bonded poly(methyl methacrylate) (PMMA) shell by surface initiated atom transfer radical polymerization (ATRP) was reported. First, the initiator for ATRP was covalently bonded onto the surface of zinc oxide nanoparticles through our novel method. Firstly, the surface of ZnO nanoparticle was treated with 3-aminopropyl triethoxysilane, a silane coupling agent, and then this functionalization nanoparticle was reacted with α-chloro phenyl acetyl chloride to prepare atom transfer radical polymerization macroinitiator. The metal-catalyzed radical polymerization of MMA with ZnOmacroinitiator was performed using a copper catalyst system to give the ZnO-based nanoparticles hybrids linking PMMA segments (poly (methyl methacrylate)/zinc oxide nanocomposite). These hybrid nanoparticles had an exceptionally good dispersability in organic solvents and were subjected to detailed characterization using FTIR, TEM and TGA and DSC analyzed.

Synthesis of chitin-graft-polystyrene via atom transfer radical polymerization initiated from a chitin macroinitiator

In this study, we synthesized chitin-graft-polystyrene by graft polymerization of styrene from a chitin macroinitiator via atom transfer radical polymerization (ATRP). First, the chitin macroinitiators for ATRP were synthesized by acylation of chitin with 2-bromopropionyl bromide in 1-allyl-3-methylimidazolium bromide (AMIMBr) ionic liquid. Because the products, which were obtained from reactions using 20 and 30 equiv. of 2-bromopropionyl bromide per repeating unit of chitin, were soluble in DMSO, the degrees of substitution (DS) values were calculated by 1H NMR measurement in DMSO-d6 to be 1.66 and 1.86, respectively. Then, graft polymerization of styrene from the obtained chitin macroinitiator with DS = 1.86 was performed by ATRP using N,N,N′,N′′,N′′-pentamethyldiethylene triamine and CuBr as the catalytic system. The yields of the products increased with increasing the feed ratios of styrene to chitin macroinitiator initiating site. To estimate the Mn values of the grafted polystyrenes (PSs), furthermore, separation of the PS chains from the chitin main-chain was conducted using alkaline hydrolysis. Their GPC traces were monomodal and the Mn values calculated using polystyrene standards increased with increasing the feed ratios of styrene to initiating sites.

Synthesis of biodegradable thermoplastic copolymers based on starch by atom transfer radical polymerization (ATRP): Monolayer chain growth on starch

AbstractModification of starch is increasingly being studied and starch is used for applications in which synthetic polymers have traditionally been the materials of choice. In this work the surface of starch was successfully modified by the polymerization of polystyrene and polyacrylamide by atom transfer radical polymerization (ATRP) method in dispersion medium. For this propose the bromoactylated starch was prepared by the reaction between hydroxyl groups of starch and the bromoacetyl bromide in DMA/LiCl (5%) in the presence of pyridine. The bromoactylated starch acts as macroinitiator in ATRP of styrene. The polymer chains' growth on surface of starch was clearly showed by the AFM images. Other analyses were used in this work such as FT‐IR, DSC, and TGA.

Synthesis of defined polyhedral oligosilsesquioxane-containing diblock and triblock methacrylate copolymers by atom transfer radical polymerization

Defined diblock and triblock copolymers composed of methyl methacrylate-co-glycidyl methacrylate block and 3-{3,5,7,9,11,13,15-hepta(2-methylpropyl)-pentacyclo[9.5.1.13,9.15,15.17,13]-octasiloxan-1-yl}propyl methacrylate block(s), i.e., P(MMA-co-GMA)-b-PiBuPOSSMA and PiBuPOSSMA-b-P(MMA-co-GMA)-b-PiBuPOSSMA, were synthesized by atom transfer radical polymerization (ATRP). First, monofunctional and bifunctional P(MMA-co-GMA) copolymers were synthesized by ATRP. Subsequently, these copolymers were successfully used as macroinitiators for ATRP of POSS-containing methacrylate monomer. The process showed high initiation efficiency of macroinitiators and led to products with low dispersity. The synthesized block copolymers were characterized by size exclusion chromatography, 1H-NMR spectroscopy and their glass transition temperatures were determined by differential scanning calorimetry. © 2012 Wiley Periodicals, Inc. J. Appl. Polym. Sci., 2013

Self-Healing Polymer Films Based on Thiol–Disulfide Exchange Reactions and Self-Healing Kinetics Measured Using Atomic Force Microscopy

Self-healing polymeric materials with branched architectures and reversible cross-linking functionalities at the periphery of branches were synthesized by atom transfer radical polymerization (ATRP). Poly(n-butyl acrylate) grafted star polymers were prepared by chain extension ATRP from cross-linked cores comprised of poly(ethylene glycol diacrylate). These polymers were further used as macroinitiators for the consecutive chain extension ATRP of bis(2-methacryloyloxyethyl disulfide) (DSDMA), in which way disulfide reversible cross-links (SS) were introduced at the branch peripheries. The SS cross-linked polymers were then cleaved under reducing conditions to form thiol (SH)-functionalized soluble star polymers. The SH-functionalized star polymer solutions were deposited on silicon wafer substrates and converted to insoluble SS re-cross-linked films via oxidation. The self-healing of prepared polymer films was studied by continuous atomic force microscopy (AFM) imaging of cuts micromachined with the AFM tip and by optical microscopy. The re-cross-linked star polymer (X3) showed a rapid spontaneous self-healing behavior, with the extent of healing dependent on the initial film thickness and the width of the cut. The self-healing behavior observed for this sample was attributed to the regeneration of SS bonds via thiol–disulfide exchange reactions. This study demonstrated the suitability of grafted multiarm polymer architectures as building blocks of self-healing polymeric materials and pointed to the importance of low intrinsic viscosity of material and high accessibility of functional groups responsible for healing.

Toughening of epoxy resin with poly(methyl methacrylate) grafted silica core-shell particles

AbstractStructurally well-defined core-shell particles were prepared by modifying the surface of silica with initiators for atom transfer radical polymerization (ATRP), and followed by using these initiator-modified particles as ATRP macro-initiators for methyl methacrylate. These particles were characterized with Fourier-transform infrared spectroscopy (FT-IR), thermo-gravimetric analysis (TGA) and scanning electron microscopy (SEM). The tethered polymer chains on the grafted silica particles were cleaved with hydrofluoric acid and measured with gel permeation chromatography (GPC). The results showed that poly(methyl methacrylate) (PMMA) chains grew from the particle surfaces in form of individual particles comprising of a hard silica core and a well-defined, densely grafted outer polymer layer. Diglycidyl ether of bisphenol-A (DGEBA) based epoxy resin was toughened with various doses of the synthesized PMMA-grafted silica particles. Resulting composite materials were characterized by tensile testing, SEM, dynamic mechanical analysis (DMA) and TGA. The results indicated that the incorporation of the core-shell particles improved the toughness of the composites without any significant deterioration of its thermal properties.

Functional Polyether-based Amphiphilic Block Copolymers Synthesized by Atom-transfer Radical Polymerization

This review deals with the synthesis, physical properties, and applications of amphiphilic block copolymers based on hydrophilic poly(ethylene oxide) (PEO) or hydrophobic poly(propylene oxide) (PPO). Oligomeric PEO and PPO are frequently functionalized by converting their OH end groups into macroinitiators for atom-transfer radical polymerization. They are then used to generate additional blocks as part of complex copolymer architectures. Adding hydrophobic and hydrophilic blocks, respectively, leads to polymers with amphiphilic character in water. They are surface active and form micelles above a critical micellization concentration. Together with recent developments in post-polymerization techniques through quantitative coupling reactions (‘click’ chemistry) a broad variety of tailored functionalities can be introduced to the amphiphilic block copolymers. Examples are outlined including stimuli responsiveness, membrane penetrating ability, formation of multi-compartmentalized micelles, etc.

Grafting of 2-Diethylaminoethyl Methacrylate onto Silk by ATRP

In order to develop silk underwear fabric with good anti-bacterial property, silk was grafted using 2-diethylaminoethyl methacrylate (DEAEMA) by atom transfer radical polymerization (ATRP) method. The amino groups and hydroxyl groups on the side chains of the silk fibroin was reacted with 2-bromoisobutyryl bromide (BriB-Br) to obtain efficient macroinitiator for ATRP. And the macroinitiator was grafted with DEAEMA in water/ethanol media using CuBr/N,N,N',N",N" -pentamethyldiethylenetriamine (PMDETA) as catalyst system. The effects of monomer concentration, the proportion of CuBr and PMDETA, grafting temperature and time on the silk grafting were discussed, and the optimal grafting technology was obtained. FT-IR characterization of the grafted silk showed a peak corresponding to DEAEMA, which indicated that DEAEMA was grafted onto the surface of silk. The quaternized grafted silk had good anti-bacterial property to S. aureus and E. coli. . And the bacteria repellency of the grafted silk had good washing durability.

A novel fluorine-containing graft copolymer bearing perfluorocyclobutyl aryl ether-based backbone and poly(methyl methacrylate) side chains

A series of novel graft copolymers consisting of perfluorocyclobutyl aryl ether-based backbone and poly(methyl methacrylate) side chains were synthesized by the combination of thermal [2π + 2π] step-growth cycloaddition polymerization of aryl bistrifluorovinyl ether monomer and atom transfer radical polymerization (ATRP) of methyl methacrylate. A new aryl bistrifluorovinyl ether monomer, 2-methyl-1,4-bistrifluorovinyloxybenzene, was first synthesized in two steps from commercially available reagents, and this monomer was homopolymerized in diphenyl ether to provide the corresponding perfluorocyclobutyl aryl ether-based homopolymer with methoxyl end groups. The fluoropolymer was then converted to ATRP macroinitiator by the monobromination of the pendant methyls with N-bromosuccinimide and benzoyl peroxide. The grafting-from strategy was finally used to obtain the novel poly(2-methyl-1,4-bistrifluorovinyloxybenzene)-g-poly(methyl methacrylate) graft copolymers with relatively narrow molecular weight distributions (M w /M n ≤ < 1.46) via ATRP of methyl methacrylate at 50 °C in anisole initiated by the Br-containing macroinitiator using CuBr/dHbpy as catalytic system. These fluorine-containing graft copolymers can dissolve in most organic solvents. This is the first example of the graft copolymer possessing perfluorocyclobutyl aryl ether-based backbone.

A pH- and temperature-sensitive macrocyclic graft copolymer composed of PEO ring and multi-poly(2-(dimethylamino) ethyl methacrylate) lateral chains

A novel method for the synthesis of macrocyclic graft copolymers was developed through combination of anionic ring-opening polymerization (AROP) and atom transfer radical polymerization (ATRP). A linear α,ω-dihydroxyl poly(ethylene oxide) with pendant acetal protected hydroxyl groups (l-poly(EO-co-EEGE)) was prepared first by the anionic copolymerization of ethylene oxide (EO) and ethoxyethyl glycidyl ether (EEGE). Then l-poly(EO-co-EEGE) was cyclized. The crude cyclized product containing the linear byproduct was hydrolyzed and purified by being treated with α-CD. The pure cyclic copolymer [c-poly(EO-co-Gly)] was esterified by reaction with 2-bromoisobutyryl bromide, and then used as ATRP macroinitiators to initiate polymerization of 2-(dimethylamino) ethyl methacrylate (DMAEMA), and a series of pH- and temperature-sensitive macrocyclic graft copolymers composed of a hydrophilic PEO as the ring and PDMAEMA as side chains (c-PEO-g-PDMAEMA) were obtained. The behavior of pH- and temperature-sensitive macrocyclic copolymers was studied in aqueous solution by fluorescence and dynamic light scattering (DLS). The critical micellization pH values of macrocyclic graft copolymers and their corresponding linear graft copolymers (l-PEO-g-PDMAEMA) were measured. Under the same conditions, the cyclic graft copolymer with the shorter side chains gave the higher critical micellization pH value. The c-PEO-g-PDMAEMA showed the lower critical micellization pH value than the corresponding l-PEO-g-PDMAEMA. The average hydrodynamic diameters (D h) of the micelles were measured by DLS with the variation of the aqueous solution pH value and temperature.