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A new strategy combing quantitative reactions and reversible-covalent chemistry is proposed for sequential synthesis of a series of sequence-controlled polymers with different sequences. Using a Michael addition reaction between acrylate and thiol, an aminolysis reaction of five-membered cyclic dithiocarbonate and a thiol substitution reaction of bromomaleimide and thiol, AB-, AB'C- and AB'CD-sequenced molecules are synthesized via AB, AB'C and AB'CD sequential monomer additions, respectively. These three molecules all have furan-protected maleimido group at one end, and the other end of AB-, AB'C- and AB'CD-sequenced molecules is amine, thiol and anthracene groups, respectively. Due to the fact that the furan-protected maleimido group can be efficiently transformed to maleimide group at high temperature via retro Diels-Alder reaction, AB-, AB'C- and AB'CD-sequenced molecules polymerize into sequence-controlled polymers with corresponding sequences at 120 °C. Through this strategy, the synthesis of molecular modules does not require separation and purification, and sequence-controlled polymers with specific sequence can be synthesized in a one-pot process via adding different monomers and adjusting reaction condition.

By combination of high trapping radical efficiency of thioketone with resonance of allylic radicals, a novel mediated agent, 1, 3, 3-triphenylprop-2-ene-1-thione (TPPT) has been successfully synthesized. 1H NMR method was used to trace the TPPT-mediated radical polymerization of butyl acrylate (BA) at 50 °C, we observed that the disappearance rates of BA, TPPT and initiator, dimethyl 2,2′-azobis (2-methylpropionate) (AIBME) have the following order: BA > AIBME > TPPT, monomer conversion increases gradually with proceeding of the polymerization and approximately 84% of conversion was obtained within 24 h of the polymerization. The molecular weights of the obtained PBA are not varied obviously with the conversion, but the molecular weight distributions are narrow. The matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) studies reveal three polymerization mechanisms. The TPPT can efficiently capture the growing PBA radicals to form PBA-TPPT• radicals, and this highly stable radicals are able to be cross-terminated by the growing PBA• radicals or primary radicals to form the dormant chains. Although the reversed reaction of reaction 1 is very slow, the extension polymerization of the PBA can undergo to form block copolymers. The molecular weight of the formed PBA is influenced by the feed molar ratio of BA/TPPT and TPPT/AIBME.

Polymerization-induced self-assembly (PISA) is an efficient and robust strategy to fabricate polymeric nano-objects. PISA enables us to prepare polymeric nano-objects in situ during the course of polymerization in concentrated solution (up to 50% w/w), making industrial production of polymeric assemblies in large-scale possible. In this work, reversible addition-fragmentation chain transfer (RAFT) dispersion copolymerization of styrene (St) and N-methacryloxysuccinimide (NMAS) was conducted with poly(2-hydroxyethyl acrylate) (PHEA) as a macro-chain transfer agent (macro-CTA) in methanol. Compared with the PHEA-mediated alcoholic dispersion polymerization of St, RAFT dispersion copolymerization of St and NMAS promoted morphology transition of nano-objects to form higher order morphologies (such as worms and vesicles). Moreover, the introduction of NMAS units into the solvophobic blocks provided functional handles for post-PISA modification of the resultant nano-objects via the active ester-amine reaction. The reaction of 1,6-hexanediamine with NMAS units in P(St-co-NMAS) blocks was conducted to afford cross-linked nano-objects with robust structural stability.

Graft copolymers with pendant macrocycles were synthesized via “graft onto” method. First, cyclic polystyrene (PS) was achieved by the combination of atom transfer radical polymerization (ATRP) and Cu-catalyzed azide–alkyne cycloaddition (CuAAc), and then an alkynyl group was introduced to cyclic PS. Meanwhile, poly(3-azide-2-hydroxypropyl methacrylate) (PGMA-N 3 ) was synthesized by ATRP of glycidyl methacrylate (GMA) and successive ring-opening of pendant epoxide ring with NaN 3 . The graft copolymer was achieved by the following click reaction between PGMA-N 3 and alkynyl-containing cyclic PS. GPC and 1 H NMR were utilized to characterize the obtained graft copolymers, and a maximal grafting density of 20% was observed. Thermal behaviors of linear PS, cyclic PS and PGMA grafted with cyclic PS (PGMA-g-cPS) were investigated by differential scanning calorimeter (DSC), and T g of PGMA-g-cPS is higher than those of linear and cyclic PS.

Various morphologies including spherical micelles, nanowires and vesicles have been prepared by reversible addition-fragmentation chain transfer (RAFT) dispersion polymerization of styrene (St) in methanol using S-1-dodecyl-S -(α,α′-dimethyl-α″-acetic acid) trithiocarbonate (TC)-terminated poly(ethylene oxide) (PEO-TC) and 2,2′-azobis(isobutyronitrile) (AIBN) as chain transfer agent and initiator, respectively. GPC, 1H NMR, TEM and laser light scattering (LLS) were used to track the polymerization. The results showed that the block copolymers PEO-b-polystyrene (PEO-b-PS) were formed firstly in homogenous polymer solution, and then the spherical micelles were produced via polymerization-induced self-assembling. Continuous polymerization of the PS blocks induced the transition of spherical micelles into other morphologies. The polymerization-induced self-assembling and reorganization (PISR) were induced by chain length ratio increase of PS to PEO blocks. The concentration of St in methanol is also important factor to influence the formation of morphologies.

Hyperbranched poly(2-((bromobutyryl)oxy)ethyl acrylate) (HPBBEA) was grafted onto the exterior surface of mesoporous silica nanoparticles (MSNs) by surface-initiated self-condensing atom transfer radical vinyl polymerization (SCATRVP). The MSNs with ATRP initiator anchored on the exterior surface (MSN-Br) were prepared by the reaction of 5,6-dihydroxyhexyl-functionalized MSNs (MSN-OH) with α-bromoisobutyryl bromide. Afterwards, MSN-Br was utilized as initiator in the SCATRVP of inimer BBEA, resulting in core–shell nanoparticles with MSN core and HPBBEA shell (MSN-g-HPBBEA). The molecular weight of HPBBEA increased with the increasing ratio of BBEA to MSN-Br. In view of the high density of bromoester groups on the surface of HPBBEA shell, MSN-HPBBEA was used to initiate the successive polymerization of (2-dimethylamino-ethylmethacrylate) (DMAEMA), forming core–shell nanoparticles MSN-g-HPBBEA-g-PDMAEMA. The resultant products were characterized by FT-IR, NMR, HRTEM and thermogravimetric analysis (TGA), etc. The pH-responsive property of MSN-g-HPBBEA-g-PDMAEMA was characterized by measuring the hydrodynamics radius at different pH values, and this core–shell nanostructure may have potential applications in biomedicine and biotechnology.

The thin films of a symmetric crystalline-coil diblock copolymer of poly(L-lactic acid) and polystyrene (PLLA-b-PS) formed lamellae parallel to the substrate surface in melt. When annealed at temperatures well above the glass transition temperature of PLLA block (T-g(PLLA)), the PLLA chains started to crystallize, leading to reorientation of lamellae. Such reorientation behavior exhibited dependence on the correlation between the crystallization temperature (T-c), the glass transition temperature of PS (T-g(PS)), the peak melting point of PLLA crystals (T-m(PLLA)), and the end melting point of PLLA crystals (T-m,end(PLLA)). When annealed at (T-c =) 80 degrees C (T-c < T-g(PS) < T-ODT, order-disorder transition temperature), 123 degrees C (T-g(PS) < T-c < T-m(PLLA) < T-ODT). 165 degrees C (T-g(PS) < T-m(PLLA) < T-c < T-m,end(PLLA) < T-ODT), the parallel lamellae became perpendicular to the substrate surface, exclusively starting at the edge of surface relief patterns. Meanwhile, the corresponding lamellar spacing was significantly enhanced.

Dendritic–linear–dendritic triblock copolymers composed of linear polystyrene (PSt) and poly(amidoamine) dendrons have been successfully synthesized. Two bromines-terminated PSt with Mn = 13,000 was prepared by atom transfer radical polymerization (ATRP) using α,α′-dibromo-p-xylene as initiator. Then the terminal bromines at both ends of PSt chains were replaced by one imine group of piperazine (PZ), and further Michael addition reaction of terminal PZ with excess 1,3,5-triacryloylhexahydro-1,3,5-triazine (TT) produced the first generation (G1) of the triblock copolymer. Continuous growth of dendrons from G1.5 to G4 at the both ends of PSt chains was carried out by the iterative Michael addition reactions with excess PZ and following TT. The ABA triblock copolymers composed of the G1–G4 dendrons and the linear PSt were obtained. Structures of the triblock polymers were characterized by GPC and 1H NMR spectra. Thermal phase transitions of the polymers were studied by DSC measurements, and all of the copolymers displayed a glass transition temperature.

The three generations dendrimer-like copolymers C(PSt(PLLA(PSt–PNAS)2)2)3 and C(PSt(PLLA(PSt–PNAS)2)2)4 have been successfully synthesized by combination of ATRP and ROP. Diethanol amine and 2,2-bis(methylene-2-bromoisobutyrate) propionyl chloride (BMBIBPC) were used as divergent reagents, respectively, before preparations of the second and the third generations. The resultant polymers were characterized by GPC and 1H NMR. Then the outermost PSt–PNAS in the dendrimer-like copolymers was cross-linked via substitution reaction of NAS with ethylene diamine, and at the same time, the PLLA segments in the second generation were decomposed in dilute THF or CHCl3 solution, forming hollow particles. The resultant morphologies were characterized by SEM and DLS methods, and spherical particles with various sizes were observed. The hollow particles may have potential applications in catalysis and bioengineering.

Novel amphiphilic block copolymers, poly(ethylene oxide)- b -poly( p -nitrophenyl methacrylate) (PEO- b -PNPMA) with controlled molecular weights and narrow molecular weight distribution were successively synthesized by ATRP of NPMA using PEO–Br as initiator. Self-assembling of the diblock copolymer PEO 113 - b -PNPMA 28 in the different solvent mixtures yielded various morphologies of star micelle-like aggregates, such as spheres, vesicles, cauliflower-like aggregates and rod-like aggregates, which are determined by the nature of the common solvents and the selective solvents. Thus the critical selective solvent contents and the solvent contents in PNPMA-rich phase were measured, and they have the following order: ethanol > methanol > water, and THF > CH 3 NO 2 > DMSO. The probable self-assembling mechanism is discussed. This method is convenient for preparation of multiple morphological star micelle-like aggregates in solution, especially from the amphiphilic block copolymers with relatively longer block shell.

Reversible addition–fragmentation chain transfer (RAFT) polymerization was used to graft polystyrene (PS) onto silica nanoparticles. A novel route was used to prepare the RAFT agent, 2-butyric acid dithiobenzoate (BDB) by substitution of dithiobenzoate magnesium bromide with sodium 2-bromobutyrate under alkali condition in aqueous solution. Epoxy groups were covalently attached to silica nanoparticles by condensation reaction of 3-glycidyloxypropyltrimethoxysilane (GPS) with the hydroxyl on the silica particle surface. RAFT agent functionalized nanoparticles were produced by ring-open reaction of the epoxy group with the carboxyl group of BDB. Then, PS chains with controlled molecular weights and narrow polydispersities (less than 1.1) were grown from the RAFT agent anchored nanoparticle surface. FT-IR, transmission electron microscopy (TEM) and thermogravimetric analysis (TGA) results showed that PS chains grew from silica particles by surface RAFT polymerization.

Well-ordered nanostructured polymeric supramolecular thin films were fabricated from the supramolecular assembly of poly(styrene-block-4-vinylpyridine) (PS-b-P4VP)(H+) and poly(methyl methacrylate)-dibenzo-18-crown-6-poly(methyl methacrylate) (PMCMA). A depression Of cylindrical nanodomains was formed by the block of P4VP(H+) and PMCMA associates surrounded by PS. The repulsive force aroused from the incompatibility between the block of P4VP(H+) and PMCMA was varied through changing the molecule weight (M-w) of PMCMA, the volume fraction of the block of P4VP(H+), and annealing the film at high temperature. Increasing the repulsive force led to a change of overall morphology from ordered nanoporous to featureless structures. The effects of solvent nature and evaporation rate on the film morphology were also investigated. Further evolution of surface morphologies from nanoporous to featureless to nanoporous structures was observed upon exposure to carbon bisulfide vapors for different treatment periods. The wettability of the film surface was changed from hydrophilicity to hydrophobicity due to the changes of the film surface microscopic composition.

Functionalized star polymers with tetraaniline on their surface have been successfully prepared by substitution reaction of N-succinimidyl-terminated star polymers with tetraaniline. A novel functional initiator bearing N-succinimidyl group was used in atom transfer radical polymerization (ATRP) of styrene, and polystyrenes (PSts) having N-succinimidyl groups with narrow molecular weight distribution were obtained. The star polymers with reactive N-succinimidyl groups on their surface were synthesized by ATRP of divinylbenzene (DVB). The N-succinimidyl-terminated PSt, polymer stars with surface N-succinimidyl groups and the PSt-b-tetraaniline stars were characterized by 1H NMR spectroscopy, FT-IR and gel permeation chromatography.

Linear pH-sensitive poly(amido amine)s were synthesized via Michael addition polymerization of N-aminoethyl piperazine (AEPZ) or 4-aminomethyl piperidine (AMPD) with 1,12-dodecylene diacrylamide (DDA). Successive Michael addition reaction of acryl-terminated poly(ethylene oxide) (A-PEO) with the secondary amine of linear poly(DDA–AEPZ) that has one secondary amine in every repeating unit afforded PEO-grafted poly(amido amine). Variation of grafting degree could be obtained conveniently via tuning the feed molar ratio of acryl/secondary amine. When this ratio equals to 1.2, all the secondary amines on the backbone of poly(DDA–AEPZ) (or poly(DDA–AMPD)) were consumed and the comb-shaped polymers were formed. The amphiphilic comb-shaped poly(DDA–AEPZ)-g-PEO was molecularly dissolved in water at pH 2.0 (w/v=0.25%), and micelles were formed when pH value of aqueous solution was adjusted to 6.5. 1H NMR data verify the formation of micelles due to the disappearance of signals attributed to poly(DDA–AEPZ). The formation of micelles can be confirmed further by TEM photos, they show that all the particles are approximately spherical and their number-average diameter is around 95 nm.

A new method to graft a large number of long polymer chains or small functional molecules onto multi-walled carbon nanotubes (MWNTs) indirectly is reported. First, MWNTs were slightly functionalized by reversible addition–fragmentation chain transfer (RAFT) copolymerization of styrene and maleic anhydride using the dithioester groups attached to MWNTs as RAFT agents. The highly reactive maleic anhydride groups could further react with a large number of long polymer chains or small functional molecules with hydroxyl or amino group easily. The resulted MWNTs have good solubility in organic solvents and water; the perfect structure of MWNTs is altered very little from the information of Raman spectra.

The free-radical polymerizations of methyl acrylate (MA) have been systematically studied under 60 Co γ-ray irradiation using benzyl propane(dithioate) ( a ), benzyl phenylethane(dithioate) ( b ), benzyl benzenecarbodithioate ( c ), benzyl 4-cyanobenzenecarbodithioate ( d ) and benzyl 4-methoxybenzenecarbodithioate ( e ) as control agents. The results indicate that Z-group of dithioester plays an important role in the polymerization behavior. When Z-group is alkyl or alkyl derivative, in the case of dithioester a and b , the polymerizations reveal quite good living characteristics except for a similar inhibition period of about 40 min, which may be attributed to the lower propagation rate coefficients during the initialization period. However, for dithioesters c , d and e , aryl as Z-group, the polymerizations show very strong inhibitions in the processes. The strong inhibition may be associated with the formation of probable 3 or 4-arm structure compounds. It is worth noting that it is the first report for dithioester a to be used as control agent in ‘controlled/living’ free radical polymerization under γ-ray irradiation.

A novel trithiocarbonate, S,S′-bis(1-(((5-ethyl-2,2-dimethyl-1,3-dioxane-5-yl)methoxy)carbonyl)propyl) trithiocarbonate (CTA-H), was synthesized in the presence of the anion-exchange resin with OH − form. And then it was used as the chain transfer agent in RAFT polymerizations of styrene (St), the polymers with controllable molecular weights and narrow molecular weight distributions were synthesized. After the terminal acetonide groups was deprotected in the presence of a cation-exchange resin with H + form, the polystyrene (PSt) with two hydroxyl groups in both chain ends was easily afforded. Then it was used as macro initiator in the cation ring open polymerization (CROP) of 1,3-dioxepane (DOP), and the well-defined H-shaped block copolymers, (PDOP) 2 PSt(PDOP) 2 , were successfully prepared. The H-shaped structure was characterized by its IR, GPC and 1 H NMR spectra, and also those of the hydrolysis products.

Hexa-armed star block copolymers, s-[poly(l-lactide)-b-poly(styrene-co-N-acryloxysuccinimide)]6 (s-[PLLA-b-poly(St-co-NAS)]6) with triphenylene core have been successively prepared by the combination of ring-opening polymerization and atom transfer radical copolymerization, and they were used in the self-assembly in tetrahydrofuran, and the micelles with triphenylene core and PLLA as inner layer as well as poly(St-co-NAS) as shell were formed. After shell was cross-linked, PLLA was hydrolyzed in aqueous NaOH solution, the hollow spheres were formed. The structures, molecular weight and polydispersity index of the polymers were characterized by their 1H NMR and FT-IR spectra, as well as GPC. Their morphologies were studied by TEM. The influence factors on the formation of various morphologies are under investigation.

Comb-shaped graft copolymers with poly(methyl acrylate) as a handle were synthesized by reversible addition–fragmentation chain transfer (RAFT) polymerization and ring-opening polymerization (ROP) techniques in three steps. First, copolymers of poly(styrene-co-chloromethyl styrene), poly(St-co-CMS), were prepared by RAFT copolymerization of St and CMS using 1-(ethoxycarbonyl)prop-1-yl dithiobenzoate (EPDTB) as RAFT agent. Second, the polymerization of MA using poly(St-co-CMS)-SC(S)Ph as macromolecular chain transfer agent produced block copolymer poly(St-co-CMS)-b-PMA. Third, cationic ring-opening polymerization of THF was performed using poly(St-co-CMS)-b-PMA/AgClO4 as initiating system to produce comb-shaped copolymers. The structures of the poly(St-co-CMS), poly(St-co-CMS)-b-PMA and final comb-shaped copolymers were characterized by 1H NMR spectroscopy and gel permeation chromatography (GPC).

An amphiphilic rod-coil ABC triblock copolymers using rigid oligo( para -phenyleneethynylene) (OPE) as the middle rod segment, poly(ethylene oxide)- block -oligo( para -phenyleneethynylene)- block -polystyrene (PEO- b -OPE- b -PS), was designed and successfully synthesized. In the synthetic route, a kind of macroinitiator, PEO- b -OPE-Br was achieved by stepwise coupling of iodo-terminated poly(ethylene oxide) and oligo( para -phenyleneethynylene) with amino end group, capping with 2-bromopropionyl bromide. Subsequently, from this macroinitiator atom transfer radical polymerization (ATRP) of styrene was performed to obtain PEO- b -OPE- b -PS. The resulting copolymers were characterized by nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). All these novel copolymers were affirmed to have well-defined structures and narrow molecular weight distributions.

With the aim to get a clear understanding of this category of polymerizations, the Michael addition polymerizations of trifunctional amines, i.e. 4-aminomethyl piperidine (AMPD), N-methyl ethylenediamine (MEDA), and 1-(2-aminoethyl) piperazine (AEPZ), with an equimolar diacrylamide, N,N′-methylene diacrylamide (MDA), were investigated. Similar to the polymerizations of these amines with an equimolar diacrylate, novel linear poly(amido amine)s containing secondary and tertiary amines in the backbones are obtained from these polymerizations as reflected by 13C NMR (INVGATE). In situ monitoring the polymerization processes using NMR shows that the reactivity sequence of three types amines in the trifunctional amines is 2° amine (original)>1° amine≫2° amine (formed), and the 2° amine (formed) is kept out of the reaction. But these results are different from those reported for the polymerizations of the similar amines with an equimolar divinyl sulfone and some diacrylates. The molecular weights and properties of poly(amindo amine)s obtained were characterized by GPC, DSC and TGA, respectively.

Star polymers based on styrene/divinyl benzene (St/DVB) and PSt- b -poly( N -isopropyl acrylamide) (NIPAAM)/DVB have been successively prepared by ‘arm-first’ method via reversible addition-fragmentation chain transfer (RAFT) polymerization. The linear macro RAFT agent PSt-SC(S)Ph was prepared by RAFT polymerization of St using benzyl dithiobenzoate and AIBN as RAFT agent and initiator. Successive RAFT polymerization of NIPAAM with PSt-SC(S)Ph as macro RAFT agent to afford diblock copolymer, PSt-b-PNIPAAM-SC(S)Ph. The coupling reactions of PSt-SC(S)Ph or PSt-b-PNIPAAM-SC(S)Ph in the presence of DVB produced the star copolymers, C(PSt) n or C(PSt-b-PNIPAAM) n . The molar ratio of DVB/PSt-SC(S)Ph and polymerization time influenced the yields, molecular weight and distribution of the star-shaped polymers, which was characterized by 1 H NMR and IR spectra, GPC measurements as well as DLS.

Highly ordered honeycomb-like macroporous films were obtained via self-assembly of a two-armed polymer with a crown ether core under controlled conditions. A possible mechanism is speculated, primarily based on the strong affinity between the crown ether cores. The pore size and arrangement are sensitive to the solvent evaporation rate and the solution concentration. Upon spontaneous drying, the pore diameter (D) depends on the concentration (c) by a relation of D=518c(-0.610).

A novel reversible addition–fragmentation chain transfer (RAFT) agent, S,S′-bis(2-hydroxylethyl-2′-butyrate)trithiocarbonate (BHEBT), was first successfully synthesized in the presence of an anion-exchange resin with OH− form, and then it was used as chain transfer agent in RAFT polymerizations of styrene or methyl acrylate, the dihydroxyl-terminated polymers with controlled molecular weights and narrow molecular weight distributions were produced, which was confirmed by GPC, 1H NMR spectra and kinetic analysis. Furthermore, these obtained telechelic polymers with trithiocarbonate group in the middle of the chains were used as macro chain transfer agents in the further RAFT polymerizations, and well-defined telechelic dihydroxyl-terminated triblock copolymers have been prepared successively. The structures were confirmed by their IR and 1H NMR spectra.

We report a novel method to prepare graft copolymers of PS-g-PEGM with controlled backbone length, grafting sites and spacing length. This method involves three steps: first step, styrene was controlled to insert into the main chain of polytrithiocarbonate at the trithiocarbonate sites, the experimental results show that not only the chain length of the backbone, but also the length of polystyrene (PS) space chain between neighboring trithiocarbonate units can be well-controlled; second step, ‘grafting points’ maleic anhydride units were inserted into the backbone chain between St unit and trithiocarbonate unit; third step, poly(ethylene glycol methyl ether) (PEGM) chains were grafted onto the main chain by esterification reaction of maleic anhydride with PEGM to form graft copolymers of PS-g-PEGM with controlled backbone length, spacing length and well-defined grafting sites.

A new graphite/polystyrene composite was produced with cationic grafting polymerization of styrene initiated by CO+ClO−4 group on the surface of expanded graphite (EG). The structures of EG and the graphite/polystyrene composite were studied with SEM and optical micrograph. The spectra of XRD and IR were used not only for confirming whether the polymerization reaction took place, but also for determining whether the polystyrene in the composite covered the surface of EG particles or intercalated into EG particles. The electrical conductivity, thermal phase transitions and mechanical properties were also discussed.

Monte Carlo simulations were used to investigate the compatibilizing effects of diblock copolymers in A/B/A–B diblock copolymer ternary blends and triblock copolymers in A/B/triblock copolymer ternary blends, respectively. The volume fraction of homopolymer A was 19% and was the dispersed phase. The simulation results show that diblock copolymers with longer A-blocks are more efficient as compatibilizers, and symmetric triblock copolymers with a shorter middle block length are easily able to bridge each other through the association of the end blocks. This kind of triblock copolymers have relatively high ability to retard phase separation as compatibilizers.

Monte Carlo method was applied to simulate self-condensing vinyl polymerization (SCVP) in the presence of multifunctional initiator with unequal reactive rate constants. Simulations showed that, with the increase of reactivity of multifunctional initiator, the molecular weight distribution decreases, the fraction of multi-armed hyperbranched polymers increases, and the best reactivity ratio of multifunctional initiator to inimor is 10/1; the reactivity difference of two active sites in inimer has strong effects on the molecular weight distribution and degree of branching. The branch degree and fraction of branch-points depend on both the conversion of double bonds and reactivity difference of two active centers in inimer, and have no relation with the adding of multifunctional initiator. The density distribution of degree of branching further shows common self-similarity in SCVP.

Block copolymers, poly(LLA- b -St)s and triblock copolymes, poly(LLA- b -St- b -MMA)s have been synthesized by the combination of the atom transfer radical polymerization (ATRP) with ring-opening polymerization (ROP) using bifunctional initiator β-hydroxylethyl α-bromoisobutyrate (HEBIB) without intermediate function transformation. The molecular weight (MW) and the molecular weight distribution (MWD) can be controlled. The structures of the copolymers were confirmed by 1 H NMR spectroscopy and GPC.

Two functional crown ether initiator, bis[4′-(2-bromobutyryl)]dibenzo-18-crown-6 (BBDC) was synthesized through the condensation of dibenzo-18-crown-6 with 2-bromobutyric acid in the presence of polyphosphoric acid. Atom transfer radical polymerizations of styrene (St), methyl acrylate, methyl methacrylate and butyl acrylate were carried out in bulk to produce the polymers with well-controlled molecular weights and narrow molecular weight distributions (1.12–1.32). Based on 1H NMR results, both the two bromides of BBDC initiated the polymerizations. The well-defined two-armed polymers were self-assemblized in the presence of potassium cations. Their morphologies of the film obtained were studied by atomic force microscopy with tapping mode.

Novel narrow distributed nanospheres with polystyrene shells and cross-linked poly(methacrylamide) (polyMMA) cores were fabricated. The cross-linking of the poly(p-nitrophenyl methacrylate) (polyNPMA) cores of micelles, formed by the self-assembly of well-defined block copolymer (poly(styrene-b-p-nitrophenyl methacrylate) (poly(St-b-NPMA))) in chloroform, was realized in the solutions directly through the reaction with ethylenediamine instead of in films as in other cases reported [3] , [8] , [9] , [10] , [11] . Further substitution of p-nitrophenol units with ammonia produced polyMMA cores. Dynamic light scattering was used to monitor the self-assembly process of poly(St-b-NPMA) in chloroform, the effects of the cross-linking and amino-substitution of the polyNPMA cores on the morphologies of the micelles, meanwhile, the changes in the chemical structures were verified by FTIR.

A series of hyperbranched polyacrylates were synthesized by self-condensing vinyl polymerization (SCVP) of 2-[(2-bromobutyryl)oxy]ethyl acrylate (BBEA). A tetrafunctional atom transfer radical polymerization (ATRP) initiator (THABI) capped with bromoisobutyrate, which has higher reactivity than the initiating site of monomer, was used as core-forming molecules. The structure and properties of the obtained polymers were characterized by NMR and SEC/RALLS/DV/RI. The effect of the tetrafunctional initiator on molecular weight and molecular weight distribution of polymers was studied.

A series of hyperbranched polymers were synthesized in high yield by self-condensing vinyl polymerization (SCVP) of 2-[(2-bromobutyryl)oxy]ethyl methacrylate (BBEM) in the presence of an ATRP initiator: THABP (a tetrafunctional initiator)/CuBr/bpy. The structure and properties of the polymers obtained were characterized by NMR and SEC/RALLS/DV/RI. The effect of the tetrafunctional initiator on degree of branching (DB), molecular weight and molecular weight distribution of polymers was studied.

Polystyrene (PSt)/polytetrahydrofuran (PTHF) A 2 B 2 miktoarm star copolymers were prepared by transformation of cationic ring-opening polymerization (CROP) to atom transfer radical polymerization (ATRP). The synthetic approach involves the synthesis of PTHF with two secondary bromine groups in the center of a macromolecular chain, (PTHF) 2 Br 2 , by the CROP of THF with the symmetric tetrafunctional initiator α,ω-dibromosebasionyl dichloride [ClCOCHBr(CH 2 ) 6 CHBrCOCl] in conjunction with silver perchlorate; (PTHF) 2 Br 2 was used to initiate the polymerization of styrene to form (PSt) 2 (PTHF) 2 star copolymer. The copolymer obtained was characterized by gel permeation chromatography and 1 H NMR spectrum. The hydrolysis of (PTHF) 2 Br 2 was also investigated.

A new four-armed tetraol, poly(1,5,7,11-tetraoxaspiro [5,5] undecane) tetraol (poly(TOSU)), was prepared by the cationic ring-opening polymerization of TOSU using BF 3 ·OEt 2 as initiator. Its structure was characterized by 1 H, 13 C NMR and FTIR spectra. GPC curves showed that the polymer obtained had two fractions with higher and lower molecular weights; however, each had a relatively narrow molecular weight distribution. The molecular weights of the polycarbonate tetraols were controlled by the molar ratio of TOSU consumed to initial BHDU. The mechanism of the polymerization was discussed.