| Supramolecular chemistry can be defined as "chemistry beyond the molecule" bearing on the organized entities of higher complexity that results from the association of two or more chemical species held together by intermolecular forces, such as hydrogen bond,coordination bond and ionic bond.Supramolecular chemistry has been considered to be a promising approach to prepare functional materials.The combination of supramolecular chemistry and polymer science has led to the emergence of supramolecular polymers,which have been gaining increasing attention due to their unique properties over covalent counterparts,such as fast and facile functionalization,reversibility and self-reparability.The ionic bond is stronger than others,feasible to be obtained in comparison with coordination bond and multiple-hydrogen bond as well as sensitive to pH,which may lead to its broad application.In this thesis,our main purpose is to develop strategies for synthesizing ion-bonded miktoarm star copolymers,especially amphiphilic ones,leading to the system combining the characteristics of miktoarm star copolymers(e.g.,microphase separation) with ones of supramolecular polymers(e.g.,reversibility).The main results are listed as following:1.A trifunctional initiator,methyl 1,3-bis(bromomethyl)benzonate(MB),was prepared and used to initiate the atom transfer radical polymerization(ATRP) of styrene.The result suggests that the polymerization of styrene with MB is a well controllable process and monoester polystyrene(PSt),namely polystyrene carrying one ester group at the middle of polymer chain,has been prepared with controlled molecular weight and low polydispersity.Then,the ester group was transformed into tertiary amino group to give dimethylamino-functionalized PSt, (PSt)2-N(CH3)2.Subsequently,the ion-bonded rod-coil copolymer,(PSt)2-OPE, was obtained by the reaction of(PSt)2-N(CH3)2 with carboxy-terminated oligo(para-phenyleneethynylene)(OPE-COOH).The resulting copolymer was characterized by proton nuclear magnetic resonance(1H NMR),Fourier transformer infrared(FTIR) and gel permeation chromatography(GPC) techniques.Vesicles and spherical micelles were generated from(PSt)2-OPE through the manipulation of the initial polymer concentration in toluene.2.A new tetrafunctional initiator,dimethyl 4,6-bis(bromomethyl)isophthalate(DBI), was synthesized and used as an initiator for ATRP of styrene.The result suggests that the polymerization of styrene with DBI is a well controllable process and diester PSt,namely polystyrene carrying two ester groups at the middle of polymer chain,has been prepared with controlled molecular weight and low polydispersity.Hydrolysis of monoester or diester PSt provides monocarboxy or dicarboxy PSt,which were used as precursors to react with poly(ethylene glycol) (PEG) end-capped with a primary amine functionality(-NH2) or a quaternary ammonium hydroxide functionality(-N+(CH2CH3)3OH-) by molecular recognition.The result suggests that the basicity of the amine plays a key role in the molecular recognition procedure.The efficiency of ionic bond formation can be enhanced from 40%upto 97%by using PEG-N+(CH2CH3)3OH- instead of PEG-NH2.(PSt)2-(PEG)2 and(PSt)2-(PEG) have been successfully prepared, which can be dissociated in dilute acid solution at room temperature.The film from(PSt)2-(PEG)2 shows nanoscopic cylindrical domain with the average diameter about 40 nm.3.Monomethoxy PEG with phenylazobenzenesulfonic acid as the terminus (PEG-N=N-SO3H) was synthesized and utilized to react with PSt2-N(CH3)2 to form ion-bonded supramolecular star copolymers(PSt2-N=N-PEG) with an azobenzene group at the core by molecular recognition.The self-assembly behavior of the copolymers with different molecular weight of PSt was investigated,which shows solid spherical aggregates in water.The aggregation andπ-πstacking of azobenzene group in water leads to the lower isomerization degree(54%) at the photostationary state compared with that in 1,4-dioxane (82%).4.In this part,we developed a novel strategy to synthesize ion-bonded miktoarm star copolymers via reversible addition-fragmentation chain transfer(RAFT) polymerization.Ion-bonded supramolecular macro-RAFT agent was synthesized from(PSt)2-(N(CH3)2)2 and 2-dodecylsulfanylthiocarbonylsulfanyl-2-methyl propionic acid(DMP) through the interaction between the tertiary amino and carboxy acid group.Then,ion-bonded amphiphilic miktoarm star copolymer, (PSt)2-poly(N-isopropylacrylamide)2,was prepared by RAFT polymerization of N-isopropylacrylamide(NIPAM) in the presence of the supramolecular macro-RAFT agent.The obtained copolymers with well-defined structure were confirmed by 1H NMR,FTIR,GPC and cleavage of the ion-bonded copolymers.5.In the last part,we presented a new water-soluble linear supramolecular polymer from N,N-bis(propylenedimethylamine)-3,4,9,10-perylenediimide(BPTA-PDI) and tartaric acid(TTA) linked by ionic andπ-πinteraction.Both of the two monomers bear two functional groups and form the linear polymer like A2 + B2 polycondensation.The two monomers are condensed along the direction ofπ-πinteraction to ensure linear character while the binding of repeating units was reinforced by ionic interaction to give the supramolecular polymer, BPTA-PDI/TTA.The self-assembly behavior of BPTA-PDI/TTA in water and ethanol was investigated and showed nanobelts with different sizes.
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