Amphiphilic diblock copolymers bearing pendant aromatic acetal groups: Synthesis and tunable pH‐triggered assembly/disassembly transition behavior

A novel aromatic acetal‐based acid‐labile monomer 2‐phenyl‐5‐ethyl‐5‐acryloxymethyl‐1,3‐dioxacyclohexane (HEDPA) was synthesized and polymerized by reversible addition fragmentation chain transfer (RAFT) polymerization using alkynyl functional chain transfer agent (CTA‐Alk). Afterward, a series of amphiphilic diblock copolymers composed of fixed hydrophobic poly(2‐phenyl‐5‐ethyl‐5‐acryloxymethyl‐1,3‐dioxacyclohexane) (PDAEP) segments and various lengths of hydrophilic mPEG segments were prepared through click reaction between alkynyl‐terminated PDAEP and azido‐terminated mPEG. The self‐assembly behaviors of the diblock copolymers were investigated by dynamic light scattering (DLS), transmission electron microscopy (TEM), fluorescence spectroscopy, and ¹H NMR. These results indicated that the diblock copolymers could self‐assemble into nano‐sized micelles with PDAEP cores and PEG coronas in aqueous solution. DLS, fluorescence spectroscopy and UV–vis spectroscopy were used to monitor the pH‐triggered assembly/disassembly transition of the micelles. These results showed that the assembly/disassembly transition behaviors of the diblock copolymers micelles can be adjusted by changing the lengths of the mPEG segments. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 1537–1547     

Highly ordered nanoporous thin films by blending of PSt‐b‐PMMA block copolymers and PEO additives as structure directing agents

Herein, we present a simple method for producing nanoporous templates with a high degree of lateral ordering by self‐assembly of block copolymers. A key feature of this approach is control of the orientation of polymeric microdomains through the use of hydrophilic additives as structure directing agents. Incorporation of hydrophilic poly(ethylene oxide) (PEO) moieties into poly(styrene‐b‐methyl methacrylate) (PSt‐b‐PMMA) diblock copolymers gives vertical alignment of PMMA cylinders on the substrate after solvent annealing. Because of the miscibility between PEO and PMMA, PEO additives were selectively positioned within PMMA microdomains and by controlling the processing conditions, it was found that ordering of PSt‐b‐PMMA diblock copolymers could be achieved. The perpendicular orientation of PMMA cylinders was achieved by increasing the molecular size of the PEO additives leading to an increased hydrophilicity of the PMMA domains and consequently to control the orientation of microdomains in PSt‐b‐PMMA block copolymer thin films. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8041–8048, 2008     

Reversible addition–fragmentation chain transfer synthesis of amidine‐based,CO2‐responsive homo and AB diblock (Co)polymers comprised of histamine and their gas‐triggered self‐assembly in water

Well‐defined homopolymers of pentafluorophenyl acrylate (PFPA) and AB diblock copolymers of N,N‐dimethylacrylamide (DMA) and poly(ethylene glycol) methyl ether acrylate (PEGA) with PFPA were prepared by reversible addition–fragmentation chain transfer (RAFT) radical polymerization. Three PFPA homopolymers of different molecular weights were reacted with the commercially available amidine and guanidine species histamine (HIS) dihydrochloride and L ‐arginine methyl ester (ARG) dihydrochloride in the presence of S‐methyl methanethiosulfonate to yield, quantitatively, the corresponding amidine and guanidine‐based acrylamido homopolymers. Both the HIS and ARG homopolymers are known to reversibly bind CO₂ with, in the case of the former, CO₂ fixation being accompanied with a switch from a hydrophobic to hydrophilic state. The RAFT synthesis of PFPA‐DMA and PEGA‐PFPA diblock copolymers yielded well‐defined materials with a range of molar compositions. These precursor materials were converted to the corresponding HIS and ARG block copolymers whose structure was confirmed using ¹H NMR spectroscopy. Employing a combination of dynamic light scattering and transmission electron microscopy, we demonstrate that the DMA‐HIS and PEGA‐HIS diblock copolymers are able to undergo reversible and cyclable self‐directed assembly in aqueous media using CO₂ and N₂ as the triggers between fully hydrophilic and amphiphilic (assembled) states. For example, in the case of the 54:46 DMA‐HIS diblock, aggregates with hydrodynamic diameters of about 40.0 nm are readily formed from the molecularly dissolved state. © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2013     

The Origin of Hierarchical Structure Formation in Highly Grafted Symmetric Supramolecular Double‐Comb Diblock Copolymers

Involving supramolecular chemistry in self‐assembling block copolymer systems enables design of complex macromolecular architectures that, in turn, could lead to complex phase behavior. It is an elegant route, as complicated and sensitive synthesis techniques can be avoided. Highly grafted double‐comb diblock copolymers based on symmetric double hydrogen bond accepting poly(4‐vinylpyridine)‐block‐poly(N‐acryloylpiperidine) diblock copolymers and donating 3‐nonadecylphenol amphiphiles are realized and studied systematically by changing the molecular weight of the copolymer. Double perpendicular lamellae‐in‐lamellae are formed in all complexes, independent of the copolymer molecular weight. Temperature‐resolved measurements demonstrate that the supramolecular nature and ability to crystallize are responsible for the formation of such multiblock‐like structures. Because of these driving forces and severe plasticization of the complexes in the liquid crystalline state, this supramolecular approach can be useful for steering self‐assembly of both low‐ and high‐molecular‐weight block copolymer systems.     

Fluorinated AB diblock copolymers and their aggregates in organic solvents

This investigation reported the preparation of fluorinated and nonamphiphilic well‐defined poly(styrene)‐block‐poly(2,2,3,3,4,4,4‐heptafluorobutyl methacrylate) (PS‐b‐PHFBMA) diblock copolymers via atom transfer radical polymerization (ATRP). Their chemical composition, structure, and bulk morphology were thoroughly investigated. In addition, their self‐assembly behavior in a dilute organic mixture solution was investigated. It was found that that the ATRP could be used to prepare the well‐defined fluorinated and nonamphiphilic PS‐b‐PHFBMA diblock copolymers in a controlled manner. The results also showed that abundant morphologies including sphere, worm‐like structure, and vesicle could be formed with different volume ratios of these two solvents, which proves that the nonamphiphilic fluorinated diblock copolymers can self‐assemble in a dilute solution, and the aforementioned reason for self‐assembly was also discussed preliminarily in this work. Finally, the effect of temperature on the aggregates was investigated to verify whether the self‐assembly behavior was to some extent temperature sensitive. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Multiple morphologies of the aggregates from self‐assembly of diblock copolymer with relatively long corona‐forming block in dilute aqueous solution

Reported here is self‐assembly behavior in selective solvent of diblock copolymers with relatively long corona‐forming block compared to core‐forming block. Three diblock copolymers, poly(ethylene glycol) monomethyl ether‐b‐poly(methacryloyl‐L ‐leucine methyl ester), also denoted as MPEG‐b‐PMALM copolymer, were prepared by fixing MPEG block with an average number of repeating units of 115, whereas varying PMALM block with an average number of repeating unit of 44, 23, 9, respectively. Multiple morphologies, such as sphere, cylinder, vesicle, and their coexisted structures from self‐assembly of these diblock copolymers in aqueous media by changing block nonselective solvent and initial polymer concentration used in preparation, were demonstrated directly via TEM observation. These results herein might, therefore, demonstrate as an example that a wide range of morphologies can be accessed not only from “crew‐cut micelles” but also from “star‐micelles” by controlling over preparation strategies. © 2009 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 364–371, 2010     

Aqueous reversible addition‐fragmentation chain transfer dispersion polymerization of thermoresponsive diblock copolymer assemblies: Temperature directed morphology transformations

In this work, we demonstrate the formation of various 3D structures formed by a structural reorganization; a process not governed by self‐assembly. First, we packaged well‐defined diblocks, thermoresponsive poly(N‐isopropylacrylamide‐b‐styrene) or P(NIPAM‐b‐STY), into spherical particles made in situ using a reversible addition‐fragmentation chain transfer (RAFT) nanoreactor technique in water to obtain high polymer solids. The resultant spheres reorganized through a temperature stimulus to form equilibrium and kinetically trapped structures; we denote this process as temperature directed morphology transformation (TDMT). Cylinder and vesicle structures, other more unusual loop, buckled sphere and cauliflower (via ultrasound) structures were observed below the lower critical solution temperature (LCST) of PNIPAM. These structures were produced efficiently, rapidly, reproducibly at high polymer solids and can be stored for years in solution or be freeze‐dried and rehydrated without a change in structure, which becomes important in biological applications. We generated the first phase diagram for the TDMT changes of thermoresponsive diblock micelles in concentrated solutions (> 7% polymer solids) produced from narrow molecular weight diblock copolymers (PDI ～ 1.1). The sphere/cylinder and cylinder/vesicle transition in the phase diagram were surprisingly found to be predominantly dictated by the length of the hydrophilic block, poly(N‐isopropylacrylamide). © 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012     

Synthesis and bulk assembly behavior of linear–dendritic rod diblock copolymers

Dendritic rod structures can be formed via the branching of dendritic elements from a primary polymer backbone; such systems present an opportunity to create nanoscale material structures with highly functional exterior regions. In this work, we report for the first time the synthesis of a hybrid diblock copolymer possessing a linear–dendritic rod architecture. These block copolymers consist of a linear poly(ethylene oxide)–poly(ethylene imine) diblock copolymer around which poly(amido amine) branches have been divergently synthesized from the poly(ethylene imine) block. The dendritic branches are terminated with amine or ester groups for the full generations and half‐generations, respectively; however, the methyl ester terminal groups can also be readily converted into alkyl groups of various lengths, and this allows us to tune the hydrophilic/hydrophobic nature of the dendritic block and, therefore, the amphiphilic properties of the diblock copolymer and its tendencies toward microphase separation. The block copolymers exhibit semicrystallinity due to the presence of the poly(ethylene oxide) block; however, as the polymer fraction consisting of poly(ethylene oxide) decreases, the overall crystallinity also decreases, and it approaches zero at generation 2.0 and higher. The unfunctionalized block copolymers show weak phase segregation in transmission electron microscopy and differential scanning calorimetry at all generations. The addition of n‐alkyl chains increases phase segregation, particularly at high alkyl lengths. The generation 3.5 polymer with n‐dodecyl alkyl substitution has a rodlike or wormlike morphology consisting of domains of 4.1 nm, equivalent to the estimated cross section of the individual polymer chains. In this case, the nanometer scale of the polymer chains can be directly observed with transmission electron microscopy. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2784–2814, 2004     

Synthesis of chiral amphiphilic diblock copolymers via consecutive RAFT polymerizations and their aggregation behavior in aqueous solution

Two chiral amphiphilic diblock copolymers with different relative lengths of the hydrophobic and hydrophilic blocks, poly(6‐O‐p‐vinylbenzyl‐1,2:3,4‐Di‐O‐isopropylidene‐D ‐galactopyranose)‐b‐poly(N‐isopropylacrylamide) or poly(VBCPG)‐b‐poly(NIPAAM) and poly(20‐(hydroxymethyl)‐pregna‐1,4‐dien‐3‐one methacrylate)‐b‐poly(N‐isopropylacrylamide) or poly(MAC‐HPD)‐b‐poly(NIPAAM) were synthesized via consecutive reversible addition‐fragmentation chain‐transfer polymerizations of VBCPG or MAC‐HPD and NIPAAM. The chemical structures of these diblock copolymers were characterized by ¹H nuclear magnetic resonance spectroscopy. These amphiphilic diblock copolymers could self‐assemble into micelles in aqueous solution, and the morphologies of micelles were investigated by transmission electron microscopy. By comparison with the lower critical solution temperatures (LCST) of poly(NIPAAM) homopolymer in deionized water (32 °C), a higher LCST of the chiral amphiphilic diblock copolymer (poly(VBCPG)‐b‐poly(NIPAAM)) was observed and the LCST increased with the relative length of the poly(VBCPG) block in the copolymer from 35 to 47 °C, respectively. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7690–7701, 2008     

Novel polymers based on atom transfer radical polymerization of 2‐methoxyethyl acrylate

Atom transfer radical polymerization (ATRP) has been employed in the polymerization of 2‐methoxyethyl acrylate (MEA) initiated by ethyl 2‐bromoisobutyrate in bulk or in toluene solution at 90–95 °C with the catalytic systems Cu(I)Br/PMDETA or HMTETA. Kinetics investigations revealed that ATRP of MEA proceeds in a controlled manner with a first‐order plot of monomer consumption, an almost linear molecular weight evolution and polydispersities < 1.29 in the entire conversion range. Well‐defined diblock copolymers with PMMA, PMEA‐b‐PMMA have been produced by use of both PMEA and PMMA macroinitiators, however, for the latter the controlled conditions were somehow difficult to maintain. The amphiphilic behavior of the diblock copolymers lead to phase separation resulting in two glass transition temperatures as detected by DSC. Contact angle (Θ) investigations with water on PMEA, PMMA, and diblock copolymers surfaces reveal PMEA as an intermediate hydrophilic with Θ ～ 50°, whereas PMMA and the diblock copolymers all fall in the hydrophobic region with Θ > 70°. © 2006 Wiley Periodicals, Inc. J Polym Sci Part Polym Chem45: 333–340, 2007     

Synthesis of amphiphilic cationic copolymers poly[2‐(methacryloyloxy)ethyl trimethylammonium chloride‐co‐stearyl methacrylate] and their self‐assembly behavior in water and water‐ethanol mixtures

A series of amphiphilic cationic random copolymers, namely poly[2‐(methacryloyloxy)ethyl trimethylammonium chloride‐co‐stearyl methacrylate] or poly(MADQUAT‐co‐SMA), have been synthesized via conventional free‐radical copolymerization using 2,2′‐azobisisobutyronitrile (AIBN) as initiator and n‐dodecanethiol as chain transfer agent. The resultant products were then characterized by FT‐IR, ¹H NMR, MALDI‐TOF MS measurements. From the number‐average molecular weights of the copolymers, we can conclude that these copolymers have oligomeric structure with a limited number of hydrophilic and hydrophobic moieties in a short polymer chain. The reactivity ratios (r_MADQUAT = 0.83, r_SMA = 0.25) between the hydrophilic MADQUAT monomer and the hydrophobic SMA monomer were calculated by the Finemann and Ross method, which was based on the results of ¹H NMR analysis. The surface activity of the random copolymers was studied by the combination of surface tension and contact angle measurement, and the results indicated that these copolymers possess relatively high surface activity. The critical aggregation concentrations (cac) of the copolymers in aqueous solution were determined by fluorescence probe method as well as surface tension measurement. The different nanoparticles of poly(MADQUAT‐co‐SMA) copolymers formed in pure water or ethanol‐water mixture were proved by the particle size and size distribution in the measurement of dynamic light scattering (DLS). Furthermore, using transmission electron microscopy (TEM), we could observe various self‐assembly morphologies of these random copolymer. All these results show that the amphiphilic cationic random copolymers have a good self‐assembly behavior, even if they are ill‐defined copolymers. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 4670–4684, 2009     

Copolymers of 2,5‐bis[(4‐methoxyphenyl) oxycarbonyl]styrene with n‐butyl acrylate: Design,synthesis, and characterization

A series of rod–coil diblock copolymers, consisting of poly{2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene} as a rigid segment and poly(n‐butyl acrylate) as a flexible part, were successfully prepared through two inverse procedures by atom transfer radical polymerization. The copolymers were characterized by ¹H NMR and gel permeation chromatography and had high molecular weights and relatively narrow polydispersities (polydispersity index < 1.20). All the block copolymers synthesized had two distinct glass‐transition temperatures according to differential scanning calorimetry. A polarizing optical microscopy investigation demonstrated the liquid crystallinity of the diblock copolymers. The self‐assembly behaviors in dilute solutions was studied by transmission electron microscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5935–5943, 2005     

Construction of PIB‐b‐PDEAEMA well‐defined amphiphilic diblock copolymers via sequential living carbocationic and RAFT polymerization

A series of well‐defined amphiphilic diblock copolymers consisting of hydrophobic polyisobutylene (PIB) and hydrophilic poly(2‐(diethylamino)ethyl methacrylate) (PDEAEMA) segments was synthesized via the combination of living carbocationic polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization. Living carbocationic polymerization of isobutylene followed by end‐capping with 1,3‐butadiene was first performed at ?70 °C to give a well‐defined allyl‐Cl‐terminated PIB with a low polydispersity (M_w/M_n =1.29). This end‐functionalized PIB was further converted to a macromolecular chain transfer agent for mediating RAFT block copolymerization of 2‐(diethylamino)ethyl methacrylate at 60 °C in tetrahydrofuran to afford the target well‐defined PIB‐b‐PDEAEMA diblock copolymers with narrow molecular weight distributions (M_w/M_n ≤1.22). The self‐assembly behavior of these amphiphilic diblock copolymers in aqueous media was investigated by fluorescence spectroscopy and transmission electron microscope, and furthermore, their pH‐responsive behavior was studied by UV‐vis and dynamic light scattering. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2014 , 52, 1478–1486     

Direct Synthesis of Double Hydrophilic Statistical Di‐ and Triblock Copolymers Comprised of Acrylamide and Acrylic Acid Units via the MADIX Process

Double hydrophilic statistical, diblock and triblock copolymers comprised of acrylamide and acrylic acid units have been synthesized in aqueous medium using the MADIX process. Starting from an either monofunctional or difunctional xanthate, the resulting AB and ABA‐type double hydrophilic block copolymers (DHBC) exhibited molar masses predetermined by the initial monomer/xanthate precursor molar ratio and polydispersity indices in the range 1.2–1.5. Batch copolymerizations yielded well‐defined statistical copolymers that were chain‐extended for the synthesis of novel poly‐ (acrylic acid‐stat‐acrylamide)‐block‐polyacrylamide DHBC.     

Synthesis of amphiphilic star block copolymers via diethyldithiocarbamate‐mediated living radical polymerization

(AB)_f star block copolymers were synthesized by the radical polymerization of a poly(t‐butyl acrylate)‐block‐poly(methyl methacrylate) diblock macroinitiator with ethylene glycol dimethacrylate in methanol under UV irradiation. Diblock macroinitiators were prepared by diethyldithiocarbamate‐mediated sequential living radical copolymerization initiated by (4‐cyano‐4‐diethyldithiocarbamyl)pentanoic acid under UV irradiation. The arm number (f) was controlled by the variation of the initial concentration of the diblock initiator. It was found from light scattering data that such star block copolymers (f ≥ 344) not only took a spherical shape but also formed a single molecule in solution. Subsequently, we derived amphiphilic [arm: poly(acrylic acid)‐block‐poly(methyl methacrylate)] star block copolymers by the hydrolysis of poly(t‐butyl acrylate) blocks. These amphiphilic star block copolymers were soluble in water because the external blocks were composed of hydrophilic poly(acrylic acid) chains. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 3321–3327, 2006     

Polyisobutylene‐b‐Poly(N,N‐diethylacrylamide) well‐defined amphiphilic diblock copolymer: Synthesis and thermo‐responsive phase behavior

Polyisobutylene‐b‐poly(N,N‐diethylacrylamide) (PIB‐b‐PDEAAm) well‐defined amphiphilic diblock copolymers were synthesized by sequential living carbocationic polymerization and reversible addition‐fragmentation chain transfer (RAFT) polymerization. The hydrophobic polyisobutylene segment was first built by living carbocationic polymerization of isobutylene at ?70 ° C followed by multistep transformations to give a well‐defined (M_w/M_n = 1.22) macromolecular chain transfer agent, PIB‐CTA. The hydrophilic poly(N,N‐diethylacrylamide) block was constructed by PIB‐CTA mediated RAFT polymerization of N,N‐diethylacrylamide at 60 ° C to afford the desired well‐defined PIB‐b‐PDEAAm diblock copolymers with narrow molecular weight distributions (M_w/M_n ≤1.26). Fluorescence spectroscopy, transmission electron microscope, and dynamic light scattering (DLS) were employed to investigate the self‐assembly behavior of PIB‐b‐PDEAAm amphiphilic diblock copolymers in aqueous media. These diblock copolymers also exhibited thermo‐responsive phase behavior, which was confirmed by UV‐Vis and DLS measurements. © 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015 , 53, 1143–1150     

Radiation‐induced fabrication of polymer nanoporous materials from microphase‐separated structure of diblock copolymers as a template

Polymer nanoporous materials with periodic cylindrical holes were fabricated from microphase‐separated structure of diblock copolymers consisting of a radiation‐crosslinking polymer and a radiation‐degrading polymer through simultaneous crosslinking and degradation by γ‐irradiation. A polybutadiene‐block‐poly(methyl methacrylate) (PB‐b‐PMMA) diblock copolymer film that self‐assembles into hexagonally packed poly(methyl methacrylate) cylinders in polybutadiene matrix was irradiated with γ‐rays. Solubility test, IR spectroscopy, and TEM and SEM observations for this copolymer film in comparison with a polystyrene‐block‐poly(methyl methacrylate) diblock copolymer film revealed that poly(methyl methacrylate) domains were removed by γ‐irradiation and succeeding solvent washing to form cylindrical holes within polybutadiene matrix, which was rigidified by radiation crosslinking. Thus, it was demonstrated that nanoporous materials can be prepared by γ‐irradiation, maintaining the original structure of PB‐b‐PMMA diblock copolymer film. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 5916–5922, 2007     

Improving mechanical properties and chemical resistance of ink‐jet printer color filter by using diblock polymeric dispersants

The diblock copolymers of polystyrene and poly(tert‐butyl acrylate) (PSt‐b‐PtBA) with various molecular weights and hydrophobic/hydrophilic (styrene/acrylic acid) chain length were prepared by atom transfer radical polymerization (ATRP). Selective hydrolysis of the diblock copolymers (PSt‐b‐PtBA) resulted in amphiphilic block copolymers of polystyrene and poly(acrylic acid) (PSt‐b‐PAA). The amphiphilic block copolymers of PSt‐b‐PAA with average molecular weight (M_n) <7500 were proved to be critical in dispersing the pigments of UV curable ink‐jet inks for manufacturing the color filter. Incorporating DB2 diblock copolymer dispersants with styrene/acrylic acid ratio at 1.5 allowed more UV curable compositions in the red and blue inks without deteriorating pigment dispersing stability and jetting properties of the ink‐jet inks. The ink drops can be precisely ejected into the tiny color area. Better properties of the cured red stripe such as nanoindentation hardness and chemical resistance were found. The competing absorption of UV light by the blue pigment hindered the through cure of monomers near the interface between glass substrate and the blue stripe. This leads to lower hardness and poor chemical resistance of the UV cured blue stripe. © 2005 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 43: 3337–3353, 2005     

Synthesis,characterization, and property of amphiphilic fluorinated abc‐type triblock copolymers

Novel amphiphilic fluorinated ABC‐type triblock copolymers composed of hydrophilic poly(ethylene oxide) monomethyl ether (MeOPEO), hydrophobic polystyrene (PSt), and hydrophobic/lipophobic poly(perfluorohexylethyl acrylate) (PFHEA) were synthesized by atom transfer radical polymerization (ATRP) using N,N,N′,N″,N″‐pentamethyldiethylenetriamine (PMDETA)/CuBr as a catalyst system. The bromide‐terminated diblock copolymers poly(ethylene oxide)‐block‐polystyrene (MeOPEO‐b‐PSt‐Br) were prepared by the ATRP of styrene initiated with the macroinitiator MeOPEO‐Br, which was obtained by the esterification of poly(ethylene oxide) monomethyl ether (MeOPEO) with 2‐bromoisobutyryl bromide. A fluorinated block of poly(perfluorohexylethyl acrylate) (PFHEA) was then introduced into the diblock copolymer by a second ATRP process to synthesize a novel ABC‐type triblock copolymer, poly(ethylene oxide)‐block‐polystyrene‐block‐poly(perfluorohexylethyl acrylate) (MeOPEO‐b‐PSt‐b‐PFHEA). These block copolymers were characterized by means of proton nuclear magnetic resonance (¹H NMR) and gel permeation chromatography (GPC). Water contact angle measurements revealed that the polymeric coating of the triblock copolymer (MeOPEO‐b‐PSt‐b‐PFHEA) shows more hydrophobic than that of the corresponding diblock copolymer (MeOPEO‐b‐PSt). Bovine serum albumin (BSA) was used as a model protein to evaluate the protein adsorption property and the triblock copolymer coating posseses excellent protein‐resistant character prior to the corresponding diblock copolymer and polydimethylsiloxane. These amphiphilic fluoropolymers can expect to have potential applications for antifouling coatings and antifouling membranes. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011     

Fully biodegradable polymeric micelles based on hydrophobic‐ and hydrophilic‐functionalized poly(lactide) block copolymers

Novel amphiphilic diblock copolymers from a combination of hydrophobic‐functional poly(lactides) (PLAs) with hydrophilic‐functional PLAs or poly(malic acid), respectively, toward fully biodegradable materials for medical applications, such as micellar drug delivery systems, are reported for the first time. The presented PLA‐based polymeric micelles are characterized by their small size below 100 nm, low critical micellar concentrations, good in vitro stabilities at room and body temperature, and efficient incorporation capability of hydrophobic compounds, particularly with regard to potential drug substances. Moreover, the advantage of being totally degradable with different rates at different pH values, as investigated in medical cancer treatment, is demonstrated. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3244–3254, 2010