Synthesis and properties of copolymers of methyl methacrylate with 2,3,4,5,6‐pentafluoro and 4‐trifluoromethyl 2,3,5,6‐tetrafluoro styrenes: An intrachain interaction between methyl ester and fluoro aromatic moieties

2,3,4,5,6‐Pentafluoro and 4‐trifluoromethyl 2,3,5,6‐tetrafluoro styrenes were readily copolymerized with methyl methacrylate (MMA) by a free radical initiator. The copolymers were soluble in tetrahydrofuran and acetone. The films obtained were transparent and flexible. The glass transition temperatures (T_gs) of the copolymers were found positively deviated from the Gordon–Taylor equation. The positive deviation could be accounted for by dipole–dipole intrachain interaction between the methyl ester group of MMA and the highly fluorinated aromatic moiety, which resulted in a decrease in the segmental mobility of the polymer chains and the enhanced T_g values of the copolymers. The water absorption of PMMA was greatly decreased by copolymerization of MMA with the highly fluorinated styrenes. With as little as 10 mol % of pentafluoro styrene content in the copolymer, the water absorption was decreased to one‐third of that for pure PMMA. The fluorinated styrenes‐MMA copolymers were thermally stable up to 420 °C under air and nitrogen atmospheres. With 50 mol % of MMA in the copolymer, the copolymer was still stable up to 350 °C. Since these copolymers contain a large number of fluorine atoms, the light absorption in the region of the visible to near infrared is decreased in comparison with nonfluorinated polymers. Thus, these copolymers may be suitable for application in optical devices, such as optical fibers and waveguides. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Facile syntheses,morphologies, and optical absorptions of P3HT coil‐rod‐coil triblock copolymers

Here we report syntheses, photophysical properties, and morphologies of a series of coil‐rod‐coil ABA triblock copolymers containing highly regioregular poly(3‐hexylthiophene) (P3HT) as the central rod block. A new methodology, based on the coupling reaction between living polymeric anions [polystyrene, polyisoprene, and poly(methyl methacrylate)] and aldehyde terminated P3HT, was successfully developed to synthesize the triblock copolymers with low polydispersities. This coupling reaction was effective for building blocks with a variety of molecular weights; therefore, a good variation in compositions of the triblock copolymers could be feasibly achieved. The non‐P3HT coil segments and the solvents were found to exhibit noticeable effects on morphologies of the spin‐coated thin films. Attachment of the coil segments to P3HT did not change the optical absorption of the P3HT segment as the block copolymers were dissolved in solution regardless the chemical structure and the molecular weight of the coil segment. Interestingly, different UV–vis absorption behaviors were observed for the spin‐coated thin films of the block copolymers, which closely related to their morphologies. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3311–3322, 2010     

Interphase development in a three‐component polymer system with asymmetric mobility

We report a study on the interphase evolution in a system composed by three polymeric components with markedly different mobility distributed between two layers. One of the layers is a low‐T_g blend containing a low molecular weight polystyrene (PS) as a plasticizer (low‐M PS) and PS chains with much higher molecular weight (high‐M PS). The counterpart is a high‐T_g layer composed by polyphenylene oxide. The system was annealed at several temperatures between T_g of the polymer layers and the subsequent interphase development probed by optical sectioning with confocal Raman microspectroscopy. The profiles obtained revealed the existence of two diffusion fronts that advance in opposite directions, both showing a similar response with time and temperature. These fronts act as well‐defined boundaries that structure the interphase into three well‐defined regions with almost constant PS volume fraction. We discuss this particular phenomenology proposing a simple diffusion model that describes the main interphase features. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 48: 627–633, 2010     

Multiwalled carbon nanotubes covalently functionalized with poly(N‐vinylcarbazole) via RAFT polymerization: Synthesis and nonliner optical properties

The poly(N‐vinylcarbazole)‐grafted MWNTs (MWNT‐PVK) hybrid materials were synthesized in the presence of S‐1‐Dodecyl‐S′‐(α, α′‐dimethyl‐α″‐acetic acid) trithiocarbonate (DDAT)‐covalently functionalized multiwalled carbon nanotubes (MWNT‐DDAT) as reversible addition–fragmentation chain transfer (RAFT) agent. Incorporation of the PVK moieties onto the MWNTs surface can considerably improve the solubility and processability of MWNTs. For all MWNT‐PVK hybrid materials, they are soluble in some common organic solvents such as toluene, THF, chloroform, DMF and others. In contrast to the UV/Vis spectrum of DDAT‐PVK, which was synthesized by use of DDAT as RAFT agent under the same synthetic condition, in the visible region, the absorption spectrum of MWNT‐PVK exhibited a typical electronic absorption characteristics of solubilized carbon nanotubes, in which the absorbance decreases gradually in the range of 350–600 nm. At the same level of linear transmission the MWNT‐PVK with 79.2% PVK moieties in the material structure possesses best optical limiting performance in comparison with the other MWNT‐PVK composites, MWNTs and C₆₀. The significant NLO responses manifest the MWNT‐PVK materials suitable candidate for viable optical limiting devices. Light scattering, originating from the thermal‐induced microplasmas and/or microbubbles, is responsible for the optical limiting. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3161–3168, 2010     

On‐chip,dynamic, and cryogenic temperature monitoring via PDMS micro‐bead coatings

Polydimethylsiloxane (PDMS) microshells/beads coated onto an electrical current‐carrying wire are demonstrated for on‐chip, dynamic, cryogenic temperature measurement via monitoring optical whispering‐gallery mode (WGM) frequency shifts. PDMS is found to be capable of supporting WGM resonance at cryogenic temperatures down to 95 K, limited by the present lab‐built cryogenic working environment. The effect of the polymeric sensor diameter on temperature sensitivity is explored and discussed. The sensors are tested for their real‐time temperature monitoring capabilities and accuracy in the cryogenic temperature regime of 95–140 K, and a comparison to a theoretical model, where the electrical resistivity of nichrome wire at cryogenic temperature is also experimentally determined, is examined. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2016 , 54, 1118–1124     

Conjugation of arginine–glycine–aspartic acid peptides to thermoreversible N‐isopropylacrylamide polymers

Thermoreversible polymeric biomaterials are finding increased acceptance in tissue engineering applications. One drawback of the polymers is their synthetic nature, which does not allow direct interaction of mammalian cells with the polymers. This limitation may be alleviated by grafting arginine–glycine–aspartic acid (RGD) containing peptides onto the polymer backbone to facilitate interactions with cell‐surface integrins. Toward this goal, N‐isopropylacrylamide (NiPAM)‐based thermoreversible polymers containing amine‐reactive N‐acryloxysuccinimide (NASI) groups were synthesized. Conjugation of RGD‐containing peptides to polymers was demonstrated with ¹H NMR spectroscopy and reverse‐phase high‐pressure liquid chromatography. The conjugation reaction was optimal at 4 °C and pH of 8.0, and increased with the increasing NASI content of polymers. With a peptide grafting ratio of 0.25 mol %, there was no significant change in the lower critical solution temperature of the polymers. Finally, the NASI‐containing polymers, cast as films, on tissue culture polystyrene, were shown to conjugate to RGD‐containing peptides and support C2C12 cell attachment. We conclude that NASI‐containing thermoreversible polymers are amenable for grafting biomimetic peptides to impart cell adhesiveness to the polymers. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3989–4000, 2003     

A novel donor–donor polymeric dyad of Poly(3‐hexylthiophene‐block‐oligo(anthracene‐9,10‐diyl): Synthesis,solid‐state packing,and electronic properties

A new polymeric dyad of oligo‐anthracene‐block‐poly(3‐hexylthiophene) (Oligo‐ANT‐b‐P3HT) has been synthesized as a donor–donor dyad building block for organic photovoltaics. The polymer dyad and oligomer of anthracene‐9,10‐diyl (Oligo‐ANT) are prepared by Grignard Metathesis. The higher order of crystallinity and molecular chains ordering at solid phase reveal the intrinsic optical and electrical properties of polymeric dyad resulting in relatively higher light harvesting ability compared to the oligo(anthracene‐9,10‐diyl). The UV‐visible spectrum of (Oligo‐ANT‐b‐P3HT) in solution shows broad absorption with two sets of absorption from both anthracene and thiophene core units, covering a wide range of the visible spectrum. The test devices of the blends of polymeric dyad with fullerene C₆₁ (PCBM) show improved photovoltaic performance with a power conversion efficiency of 3.26% upon subjecting to pre‐fabrication thermal treatments. With optimized morphology of the interpenetrating network and the shorter fluorescence lifetime of the annealed dyad/PCBM blends, the effective charge transfer from the donor dyad to PCBM has evidenced. Thus, these studies will allow further synthetic advances to make potential high crystalline polymeric dyads with significantly improved light harvesting capability. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2016 , 54, 3032–3045     

ASAXS study of styrene‐grafted sulfonated poly(vinylidene fluoride) membranes

Small‐angle and wide‐angle X‐ray scattering and anomalous small‐angle X‐ray scattering were used to investigate proton‐conducting membranes prepared by radiation‐induced styrene grafting and sulfonation of commercial poly(vinylidene fluoride) (PVDF‐g‐PS) films. The membranes retain the lamellar and highly oriented structure of the original PVDF films even through excessive grafting and sulfonation. The sulfonate groups aggregate in the central part of the amorphous layers, where they form a weakly ordered structure that does not show any preferred orientation. This structure is suggested to be lamellar with alternate metal‐sulfonated hydrate and PVDF‐g‐PS layers. The lamellar period is 15.1 Å. © 2000 John Wiley & Sons, Inc. J Polym Sci B: Polym Phys 38: 1734–1748, 2000     

Diels–Alder modification of poly(ethylene terephthalate‐co‐anthracene‐2,6‐carboxylate) with N‐substituted maleimides

Dimethyl 2,6‐anthracene dicarboxylate is used as a comonomer in the synthesis of functional copolymers that are subject to modification with Diels–Alder reactions. The formation of poly(ethylene terephthalate‐co‐2,6‐anthracenate), containing less than 20 mol % of the anthracene‐2,6‐dicarboxylate structural units, provides materials that are tractable and soluble. The anthracene units of the copolymers undergo Diels–Alder reactions with N‐substituted maleimides. The grafting of N‐alkylmaleimides affords soluble, hydrophobic polymers, whereas grafting with maleimide‐terminated poly(ethylene glycol) affords hydrophilic polymers. Because this reaction proceeds below the melting point of the copolymers, the procedure can be applied to thin films, whereby the surface properties are modified. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 40: 3256–3263, 2002     

Thermal behavior of poly(vinylbenzyl chloride)‐grafted poly(ethylene‐co‐tetrafluoroethylene) films

The effect of the degree of grafting (DOG) on the thermal behavior of poly(vinylbenzyl chloride)‐grafted poly(ethylene‐co‐tetrafluoroethylene) (ETFE‐g‐PVBC) films was investigated by differential scanning calorimetry (DSC), X‐ray diffraction (XRD), dynamic mechanical analysis ( DMA), FT‐IR, and thermogravimetric analysis (TGA) instruments. Several ETFE‐g‐PVBC films with various degrees of grafting, including 10, 24, 41, 60, and 94%, were prepared using a radiation grafting technique. The DSC and XRD results of the ETFE‐g‐PVBC films revealed that the crystallinity of the films decreased as the DOG increased. The DMA and FT‐IR results of the films indicated that a crosslinking reaction occurred at temperatures above 250 °C. In the thermal properties of the grafted films, an increase in the DOG led to an increase in the decomposition temperature. The activation energy (E_a) of the thermal decomposition was calculated using Kissinger's equation from TGA results. The E_a value of the PVBC graft chain was found to increase as the DOG increased, indicating that the crosslinking reaction of ETFE‐g‐PVBC films increased with an increase in the DOG during the thermal degradation process. © 2014 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2014 , 52, 517–525     

Synthesis of polymeric core–shell particles using surface‐initiated living free‐radical polymerization

An easy and novel approach to the synthesis of functionalized nanostructured polymeric particles is reported. The surfactant‐free emulsion polymerization of methyl methacrylate in the presence of the crosslinking reagent 2‐ethyl‐2‐(hydroxy methyl)‐1,3‐propanediol trimethacrylate was used to in situ crosslink colloid micelles to produce stable, crosslinked polymeric particles (diameter size ～ 100–300 nm). A functionalized methacrylate monomer, 2‐methacryloxyethyl‐2′‐bromoisobutyrate, containing a dormant atom transfer radical polymerization (ATRP) living free‐radical initiator, which is termed an inimer (initiator/monomer), was added to the solution during the polymerization to functionalize the surface of the particles with ATRP initiator groups. The surface‐initiated ATRP of different monomers was then carried out to produce core–shell‐type polymeric nanostructures. This versatile technique can be easily employed for the design of a wide variety of polymeric shells surrounding a crosslinked core while keeping good control over the sizes of the nanostructures. The particles were characterized with scanning electron microscopy, transmission electron microscopy, optical microscopy, dynamic light scattering, and Raman spectroscopy. © 2007 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1575–1584, 2007     

Low‐band gap copolymers containing thienothiadiazole units: Synthesis,optical, and electrochemical properties

Novel low‐band gap alternating copolymers consisting of 9,9‐bis(2‐ethylhexyl)fluorene and 4,6‐di(2‐thienyl)thieno[3,4‐c][1,2,5]thiadiazole and its 3,3″‐dialkyl derivatives were synthesized by Suzuki copolymerization reaction, and their photophysical and electrochemical properties were studied. The copolymers possess small optical band gap 1.3–1.4 eV. The absorption covers the whole visible spectral region. The long‐wavelength absorption maxima in thin films located at approximately 750–785 nm are significantly red shifted compared with those in solution, indicating strong intermolecular interactions. The introduction of alkyl chains to the thiophene units increases the molecular weights of soluble fractions and solubility of the final copolymers, leading to the improved processability of thin films. Polymer solutions exhibited solvatochromism and thermochromism, which is strongly supported by the involvement of the alkyl chains. The copolymers exhibited ambipolar redox properties and reversible electrochromic behavior. The electronic properties are influenced only slightly by alkyl substituents. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2743–2756, 2010     

Conformation and luminescence characteristics of nanopoly[2‐metoxy‐5‐(2′‐ethyl‐hexyloxy)‐p‐phenylene vinylene] in two‐dimensional arrays

With anodic alumina with an ordered nanopore array used as a template, poly[2‐metoxy‐5‐(2′‐ethyl‐hexyloxy)‐p‐phenylene vinylene] (MEH–PPV) was embedded into the nanopores, and then two‐dimensional arrays of light‐emitting nanopolymers were prepared. By the measurement and analysis of photoluminescence and photoluminescence excitation spectra of the samples, it was demonstrated that the optical properties of the nano‐MEH–PPV arrays were obviously different from those of MEH–PPV films. The conformations of the MEH–PPV chains in the nanopores, films, and solutions and their effects on the optical properties were examined. It was determined experimentally that the conformations of the MEH–PPV chains in the solutions were maintained in the nano‐MEH–PPV arrays. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3037–3041, 2006     

Synthesis of UV‐cured acrylic–silica hybrid nanocomposites from dendritic acrylic oligomer and acrylic‐functionalized silica

An acrylic–silica hybrid polymeric nanocomposite, comprising well‐distributed silica nanoparticles in acrylic matrix, has been synthesized at a markedly rapid rate from a dendritic acrylic oligomer (DAO) and an acrylic‐functionalized silica (A‐silica) via UV‐curing. A‐silica was made by functioning colloidal silica nanoparticles with 3‐methacryloxypropyltrimethoxysilane (MATMS) and DAO was formed by reacting 1,5‐diamino‐2‐methylpentane (MPMDA) with trimethylopropane triacrylate (TMPTA). The MATMS has been found either doubly or singly bonded to silica nanoparticles but not triply bonded, and the inclusion of MATMS into the siloxane network structure increases the size of silica nanoparticles. The well distribution of A‐silica and its good compatibility with DAO cause an increase in T_d of the acrylic–silica hybrid material. Silica nanoparticles are too small to cause any significant light scattering, and do not have deleterious effects on transparency. The “hybrid‐on‐polyethylene terephathalate” films exhibited satisfactory hardness and surface roughness because of silica nanoparticles. The preparation as well as the characterization of the constituting species and the final hybrid material are described in detail. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 8149–8158, 2008     

The preparation of amphiphilic core‐shell nanospheres by using water‐soluble macrophotoinitiator

The amphiphilic poly(AM‐co‐SA)‐ITXH macrophotoinitiator was synthesized by precipitation photopolymerization under UV irradiation with isopropylthioxanthone (ITX) as free radical photoinitiator. A novel method has been developed to prepare amphiphilic core‐shell polymer nanospheres via photopolymerization of methyl methacrylate (MMA) in aqueous media, with amphiphilic copolymer macrophotoinitiator poly(AM‐co‐SA)‐ITXH. During polymerization, the amphiphilic macroradicals underwent in situ self‐assembly to form polymeric micelles, which promoted the emulsion polymerization of the monomer. Thus, amphiphilic core‐shell nanospheres ranging from 70 to 140 nm in diameter were produced in the absence of surfactant. The conversion of the monomer, number average molecular weights (M_n), and particle size were found to be highly dependent on the macrophotoinitiator and monomer concentration. The macrophotoinitiator and amphiphilic particles were characterized by FTIR, UV‐vis, ¹H NMR, TEM, DSC, and contact angle measurements. The results showed the particles had well‐defined amphiphilic core‐shell structure. This new method is scientifically and technologically significant because it provides a commercially viable route to a wide variety of novel amphiphilic core‐shell nanospheres. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 936–942, 2010     

Synthesis and characterization of donor–acceptor poly(3‐hexylthiophene) copolymers presenting 1,3,4‐oxadiazole units and their application to photovoltaic cells

We have used Grignard metathesis polymerization to prepare poly(3‐hexylthiophene)‐based copolymers containing electron‐withdrawing 4‐tert‐butylphenyl‐1,3,4‐oxadiazole‐phenyl moieties as side chains. We characterized these copolymers using ¹H and ¹³C nuclear magnetic resonance spectroscopy, thermogravimetric analysis, and gel permeation chromatography. The band gap energy of copolymer was determined from the onset of the optical absorption. The quenching effects were observed in the photoluminescence spectra of the copolymers incorporating pendant electron‐deficient 1,3,4‐oxadiazole moieties on the side chains. The photocurrents of devices were enhanced in the presence of an optimal amount of the 1,3,4‐oxadiazole moieties, thereby leading to improved power conversion efficiencies. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3331–3339, 2010     

Synthesis of polymeric microspheres from a Merrifield resin by surface‐initiated nitroxide‐mediated radical polymerization

Polymeric microspheres were prepared from a Merrifield resin via nitroxide‐mediated radical polymerization. Polystyrene, poly(acetoxystyrene), and poly[styrene‐b‐(methyl methacrylate‐co‐styrene)], poly(acetoxystyrene‐b‐styrene), and poly(styrene‐co‐2‐hydroxyethyl methacrylate) copolymers were demonstrated to graft onto 2,2,6,6‐tetramethyl‐1‐piperidinyloxy nitroxide bound Merrifield resins. The polymerization control was enhanced both on the surface and in solution by the addition of sacrificial nitroxide. The significant increase in the particle diameter (more than a fivefold volume increase for polystyrene brushes) showed that polymer growth was not only on the surface but also within the particles, and this diameter increase could be adjusted through changes in the molecular weight of the polymers. The microspheres were characterized by elemental analysis, IR spectroscopy, particle size analysis, and optical microscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 2145–2154, 2005     

Synthesis,photoluminescence, and electrochromism of polyamides containing (3,6‐di‐tert‐butylcarbazol‐9‐yl)triphenylamine units

A new carbazole‐derived, triphenylamine (TPA)‐containing aromatic dicarboxylic acid monomer, 4,4′‐dicarboxy‐4″‐(3,6‐di‐tert‐butylcarbazol‐9‐yl)TPA, was synthesized, and it led to a series of electroactive aromatic polyamides with main‐chain TPA and pendent 3,6‐bis(tert‐butyl)carbazole units by reacting it with various aromatic diamines via the phosphorylation polyamidation technique. The polyamides were amorphous with good solubility in many organic solvents and could be solution‐cast into flexible and strong films. They showed high glass‐transition temperatures (282–335 °C) and high thermal stability (10% weight loss temperatures >480 °C). The electroactive polymer films had well‐defined and reversible redox couples with good cycle stability in acetonitrile solutions. The polymer films also exhibited fluorescent and multielectrochromic behaviors. The anodically electrochromic polyamide films had moderate coloration efficiency (～100 cm²/C) and high optical contrast ratio of transmittance change (Δ%T) up to 47% at 813 nm and 48% at 414 nm for the green coloring. After hundreds of cyclic switches, the polymer films still retained good redox and electrochromic activity. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Iridium complex grafted to 3,6‐carbazole‐alt‐tetraphenylsilane copolymers for blue electrophosphorescence

We designed a 3,6‐dibromo‐9‐hexyl‐9H‐carbazole derivative with the blue emissive iridium complex bis[2‐(4,6‐difluorophenyl)pyridyl‐N,C^2′](picolinato)iridium(III) (FIrpic) linked at the alkyl terminal. Based on this monomer, novel 3,6‐carbazole‐alt‐tetraphenylsilane copolymers grafted with FIrpic were synthesized by palladium‐catalyzed Suzuki coupling reaction, and the content of FIrpic in the polymers could be controlled by feed ratio of the monomers. The polymer films mainly show blue emission from FIrpic, and the emission intensity from the polymer backbones is much weaker compared with the doped analogues, which demonstrates an efficient energy transfer from polymeric host to covalently bonded guest. The phase separation in the polymers was suppressed, which can be identified by atomic force microscopy and designed electroluminescent (EL) devices. EL devices based on the polymers exhibited blue phosphorescence from FIrpic. The luminous efficiency of preliminary devices reached 2.3 cd/A, and the efficiency roll‐off at high current densities was suppressed. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 1859–1865, 2010     

Effect of residual water and free volume on the glass‐transition temperature and heat capacity in polystyrene/poly(vinyl acetate‐co‐butyl acrylate) structured latex films

The dynamic heat capacity and glass‐transition temperature of polystyrene (PS)/poly(vinyl acetate‐co‐butyl acrylate) (VAc–BA) (50:50 w/w) structured latex films as a function of annealing time at 70, 77, and 85 °C were examined with modulated‐temperature differential scanning calorimetry. The PS and poly(vinyl acetate‐co‐n‐butyl acrylate) components were considered to be the cores and shells, respectively, in the structured latex. The dynamic heat capacity decreased with time. The glass‐transition temperatures of the PS and VAc–BA phases shifted to higher values after annealing. The results of thermogravimetry showed that there existed about 1.8% residual water in the films. The mean free volume and relative concentration of holes at room temperature (before and after annealing) and 85 °C, as a function of time, were obtained with positron annihilation lifetime spectroscopy (PALS). The PALS results indicated no significant change in free volume during annealing. It is believed that the loss, by diffusion, of residual water mainly caused a decrease in heat capacity and an increase in the glass‐transition temperatures. As little as 1.8% residual water in the structured latex films had a significant influence on the thermal properties. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1659–1664, 2001