Few layer COFs was incorporated with rGO to provide composite cathode materials with improved energy storage capability.

A series of well-defined asymmetric centipede-like copolymers, containing polyacrylate backbone, hydrophilic poly(ethylene glycol), and hydrophobic polystyrene side chains, was synthesized by successive atom transfer radical polymerization. The grafting-through strategy was first employed for the preparation of poly-[poly(ethylene glycol) methyl ether acrylate] comb copolymer. The grafting-from route was used following for the synthesis of the final amphiphilic centipede-like copolymer, poly[poly(ethylene glycol) methyl ether acrylate]g-polystyrene. At each grafting point, two different chains are connected and the spacing between the grafting points is constant. Polystyrene side chains were connected to the polyacrylate backbone through stable C-C bonds instead of ester connections. The molecular weights of both the backbone and the side chains were controllable. The molecular weight distributions were in the range of 1.24-1.38. The critical micelle concentrations of these amphiphilic centipede-like graft copolymers in water were determined by fluorescence probe technique. The morphologies of the micelles formed from these centipede-like graft copolymers were preliminarily explored by TEM and were found to be spheres.

A new acrylamide monomer bearing isopropylamide and N,N-diethylamino ethyl groups in the side chain, i.e., N-(2-(diethylamino)ethyl)-N-(3-(isopropylamino)-3-oxopropyl)acrylamide (DEAE-NIPAM-AM), was synthesized through Aza-Michael addition reaction followed by amidation with acryloyl chloride. The homopolymers, poly(N-(2-(diethylamino)ethyl)-N-(3-(isopropylamino)-3-oxopropyl)-acrylamide)s [poly(DEAE-NIPAM-AM)], with controlled molecular weights and relatively narrow molecular weight distributions were then prepared via RAFT polymerization. The lower critical solution temperature (LCST) of the homopolymer was examined to be influenced by molecular weight, salt concentration, and pH value of aqueous solution. The LCST of the homopolymer could be tuned in a wide temperature window by changing the pH value of aqueous solution, and it increased with the decrease of pH value. Particularly, CO 2 gas as a unique pH stimulus can also reversibly adjust the solubility of homopolymer without the addition of acids or bases. S timuli-responsive polymers able to respond to external stimuli have attracted increasing attention since these kinds of polymers have broad applications in areas from material science to biology. 1 For relevant applications, however, the change in behavior of a macromolecule (protein and nucleic acid) is often not the result of a single factor but a combination of environmental changes. 2 To mimic this feature, formulation of multistimulus responsive polymers by incorporating different stimulus-sensitive moieties has spurred significant interest. 3 Among them, temperature and pH dual-responsive polymers were widely studied due to the convenience in adjusting environmental pH and temperature and the ease in the preparation of "smart materials" on the basis of temperature and pH dual-responsive polymers. In general, block and random copolymers are relatively common in doubleresponsive systems by simply connecting moiety with pHstimulus property with the other segment with temperaturestimulus behavior. 3−9 For the block copolymer, time-consuming steps in the preparation and purification are usually required to obtain well-defined and pure block copolymers. In addition, the self-assembly of some certain block copolymers in solution is often observed due to the mutual incompatibility of different blocks, which might retard their relative applications. 3,4 pHand temperature-

A series of well‐defined double‐hydrophilic graft copolymers, consisting of poly(N‐isopropylacrylamide)‐b‐poly(ethyl acrylate) (PNIPAM‐b‐PEA) backbone and poly(2‐(dimethylamino)ethyl acrylate) (PDMAEA) side chains, were synthesized by the combination of single‐electron‐transfer living radical polymerization (SET‐LRP) and atom‐transfer radical polymerization (ATRP). PNIPAM‐b‐PEA backbone was first prepared by sequential SET‐LRP of N‐isopropylacrylamide and 2‐hydroxyethyl acrylate at 25 °C using CuCl/tris(2‐(dimethylamino)ethyl)amine as catalytic system followed by the transformation into the macroinitiator by treating the pendant hydroxyls with 2‐chloropropionyl chloride. The final graft copolymers with narrow molecular weight distributions were synthesized by ATRP of 2‐(dimethylamino)ethyl acrylate initiated by the macroinitiator at 40 °C using CuCl/tris(2‐(dimethylamino)ethyl)amine as catalytic system via the grafting‐from strategy. These copolymers were employed to prepare stable colloidal gold nanoparticles with controlled size in aqueous solution without any external reducing agent. The morphology and size of the nanoparticles were affected by the length of PDMAEA side chains, pH value, and the feed ratio of the graft copolymer to HAuCl4. © 2009 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 47: 1811–1824, 2009

π-Conjugated nanofibers of controlled length and composition show promising potential applications from biomedicine to optoelectronics. However, efficient preparation of uniform nanofibers from π-conjugated polymers with precise control over length and composition poses an outstanding challenge. Herein, we report the synthesis of a suite of block copolymers (BCPs) containing πconjugated crystalline oligo(p-phenylene ethynylene) (OPE) segments of different chain lengths and a poly(N-isopropylacrylamide) (PNIPAM) or a poly(2-vinylpyridine) (P2VP) block (OPE 5 -b-PNIPAM 47 , OPE 7 -b-PNIPAM 47 , OPE 9 -b-PNIPAM 47 , and OPE 9 -b-P2VP 56 ; subscripts indicate the number of repeat units). The length of OPE segment significantly affected the self-assembly OPE-based BCPs. OPE 5 -b-PNIPAM 47 chains were molecularly dissolved in ethanol. Although OPE 7 -b-PNIPAM 47 formed fiber-like micelles of uniform width initially, these micelles were not frozen at room temperature (23 °C), leading to the transformation from regular fiber-like micelles to irregular spherical aggregates upon aging for 7 days. Polydisperse fiber-like micelles of uniform width with kinetically frozen morphology at 23 °C were formed for OPE 9 -b-PNIPAM 47 in ethanol by a direct heating−cooling cycle. The results were supported by the observations in dynamic light scattering, UV−vis, and fluorescence measurements, which indicated the resistance of OPE-based micelles toward micelle dissolution increased with the rising of OPE chain length. By the self-seeding approach of living crystallization-driven self-assembly (CDSA), uniform continuous micelles of controlled length (∼40 nm−1.2 μm) consisting of an OPE core and PNIPAM or P2VP shell can be obtained although micelles of OPE 9 -b-PNIPAM 47 and OPE 9 -b-P2VP 56 exhibited different resistance toward micelle dissolution. Significantly, a series of uniform segmented OPE-based fiber-like comicelles and their hybrid nanostructures with excellent length and composition tunability can be achieved by the seeded growth approach of living CDSA. Overall, we provided a facile access to the fabrication of OPE-based nanofibers with precise control over their length and composition along with instructive information about the influence of structure of π-conjugated block on the CDSA of BCPs containing a crystalline π-conjugated segment.

A series of well-defined amphiphilic graft copolymers consisting of hydrophilic poly(acrylic acid) backbone and hydrophobic poly(propylene oxide) side chains were synthesized by sequential reversible addition-fragmentation chain transfer (RAFT) polymerization and atom transfer nitroxide radical coupling (ATNRC) chemistry followed by selective hydrolysis of poly(tert-butyl acrylate) backbone. A new Br-containing acrylate monomer, tert-butyl 2-((2-bromopropanoyloxy)methyl) acrylate, was first prepared, and it can be polymerized via RAFT in a controlled way to obtain a well-defined homopolymer with narrow molecular weight distribution (M w /M n =1.06). Grafting-onto strategy was employed to synthesize PtBA-g-PPO well-defined graft copolymers with narrow molecular weight distributions (M w /M n =1.05-1.23) via ATNRC reaction between Br-containing PtBA-based backbone and poly(propylene oxide) with 2,2,6, 6-tetramethylpiperidine-1-oxyl (TEMPO) end group using CuBr/PMDETA or Cu/PMDETA as catalytic system. The final PAA-g-PPO amphiphilic graft copolymers were obtained by the selective acidic hydrolysis of PtBA backbone in acidic environment without affecting the side chains. The critical micelle concentrations in aqueous media were determined by a fluorescence probe technique. Diverse micellar morphologies were formed with varying the content of hydrophobic PPO segment.

A series of well-defined ferrocene-based amphiphilic graft copolymers, consisting of poly(N-isopropylacrylamide)-b-poly(ethyl acrylate) (PNIPAM-b-PEA) backbone and poly(2-acryloyloxyethyl ferrocenecarboxylate) (PAEFC) side chains, were synthesized by the combination of single-electron-transfer living radical polymerization (SET-LRP) and atom transfer radical polymerization (ATRP). A new ferrocene-based monomer, 2-(acryloyloxy)ethyl ferrocenecarboxylate (AEFC), was prepared first and it can be polymerized via ATRP in a controlled way using methyl 2-bromopropionate as initiator and CuBr/PMDETA as catalytic system in DMF at 40 C. PNIPAM-b-PEA backbone was synthesized by sequential SET-LRP of NIPAM and HEA at 25 C using CuCl/Me 6 TREN as catalytic system followed by the transformation into the macroinitiator by treating the pendant hydroxyls with a-bromoisobutyryl bromide. The targeted well-defined graft copolymers with narrow molecular weight distributions (M w /M n \ 1.20) were synthesized via ATRP of AEFC initiated by the macroinitiator. The electro-chemical behaviors of PAEFC homopolymer and PNIPAM-b-(PEA-g-PAEFC) graft copolymer were studied by cyclic voltammetry. Micellar properties of PNIPAM-b-(PEA-g-PAEFC) were investigated by transmission electron microscopy and dynamic light scattering.

A series of well-defined double hydrophilic graft copolymers, consisting of poly(N-isopropylacrylamide)-b-poly(ethyl acrylate) (PNIPAM-b-PEA) backbone and poly(2-(diethylamino)ethyl methacrylate) (PDEA) side chains, were synthesized by successive atom transfer radical polymerization (ATRP). The backbone was firstly prepared by sequential ATRP of N-isopropylacrylamide and 2-hydroxyethyl acrylate at 25 8C using CuCl/tris(2-(dimethylamino)ethyl)amine as catalytic system. The obtained diblock copolymer was transformed into macroinitiator by reacting with 2chloropropionyl chloride. Next, grafting-from strategy was employed for the synthesis of poly(N-isopropylacrylamide)-b-[poly(ethyl acrylate)-g-poly(2-(diethylamino)ethyl methacrylate)] (PNIPAM-b-(PEA-g-PDEA)) double hydrophilic graft copolymer. ATRP of 2-(diethylamino)ethyl methacrylate was initiated by the macroinitiator at 40 8C using CuCl/hexamethyldiethylenetriamine as catalytic system. The molecular weight distributions of double hydrophilic graft copolymers kept narrow. Thermo-and pH-responsive micellization behaviors were investigated by fluorescence spectroscopy, 1 H NMR, dynamic light scattering, and transmission electron microscopy. Unimolecular micelles with PNIPAM-core formed in acidic environment (pH ¼ 2) with elevated temperature (!32 8C); whereas, the aggregates turned into vesicles in basic surroundings (pH ! 7.2) at room temperature.