【作者】 鲁代仁；

【导师】 白如科；

【作者基本信息】 中国科学技术大学 ， 高分子化学与物理， 2009， 博士

【摘要】 超分子化学是研究两种及两种以上的化学物种通过分子间相互作用结合在一起而形成的具有特定结构和功能的超分子体系的科学,被认为是具有发展前景的制备功能材料的新方法之一。将超分子的概念引入到高分子科学中,即所谓的超分子聚合物,它是指聚合物的组分（小分子或者大分子）以非共价键结合在一起,无论是本体,还是在稀或浓溶液,都具有聚合物的特点。与传统聚合物相比,超分子聚合物的最大特点是合成快速、功能化方便,形成过程可逆,具有自修复功能。与氢键和配位键相比,离子键键能较大,热稳定性高,对pH值敏感,在适当条件下具有可逆性,且形成离子键的官能团（如羧基、氨基）容易制备。本论文从分子结构设计出发,设计、合成了多种离子键星形杂臂共聚物,建立了合成离子键星形共聚物的两种方法,并研究了离子键星形杂臂共聚物的自组装行为。主要内容分为如下五个部分:一、通过3,5-二甲基苯甲酸的酯化、溴化反应,合成一种三官能团引发剂,1,3-二溴甲基苯甲酸甲酯（MB）,用它引发苯乙烯的原子转移自由基聚合（ATRP）得到单酯基位于聚合物链中间的聚苯乙烯。酯基经N,N-二甲基-1,3-丙二胺（DPA）胺解得到单叔胺基聚苯乙烯（（PSt）₂-N（CH₃）₂）,与羧基封端的对亚苯基亚乙炔撑齐聚物（OPE-COOH）分子识别形成了离子键三杂臂rod-coil共聚物,（PSt）₂-OPE。聚合物通过红外（IR）、核磁共振氢谱（¹H NMR）和凝胶渗透色谱（GPC）表征。研究了（Pst）₂-OPE在甲苯中的自组装行为。透射电镜和光散射研究表明,共聚物的甲苯溶液随着浓度的增加,聚集态结构从囊泡转变成实心胶束,并且伴随很强的荧光淬灭现象。这是共轭结构的OPE在甲苯中堆积的结果。二、间二甲苯经过溴甲基化、氧化、酯化和溴化等反应合成了一种新型的四官能团引发剂,4,6-二（溴甲基）-1,3-苯二甲酸甲酯（DBI）,并用它引发苯乙烯的ATRP聚合,动力学研究表明聚合反应是活性/可控聚合,得到双酯基位于聚合物链中间的聚苯乙烯。单、双酯基聚苯乙烯经水解生成单、双羧基聚苯乙烯,与氨基（-NH₂）或季铵碱（-N⁺Et₃OH^-）封端的聚乙二醇（PEG）分子识别形成超分子两亲性共聚物。实验证实,氨基的碱性对识别过程起关键作用。例如,PEG-NH₂与双羧基聚苯乙烯作用时,仅有40%羧基参与反应;PEG-N⁺Et₃OH^-与双羧基聚苯乙烯作用时,97%羧基参与反应。用IR、¹H NMR、GPC对超分子聚合物共聚物（PSt）₂（PEG）₂和（PSt）₂（PEG）进行表征。由于离子键超分子聚合物具有对于pH敏感的特性,改变溶液的pH值可以很容易将这类共聚物解离。我们初步探索了超分子共聚物在硅片表面的自组装,原子力显微镜显示了共聚物形成柱状结构的纳米膜。三、合成了苯基偶氮苯磺酸封端的聚乙二醇（PEG-N=N-SO₃H）,与（PSt）₂-N（CH₃）₂分子识别形成含偶氮苯离子键两亲性三杂臂共聚物,PSt₂-N=N-PEG,偶氮苯基团位于星形聚合物链中间。¹H NMR和GPC对共聚物进行了表征。我们对PSt₂-N=N-PEG的光异构化及自组装进行了研究。在水中,偶氮苯基团排列在胶束的核与壳之间,形成面对面的H型聚集体,限制了偶氮苯聚合物的光异构化,导致其达到稳态时光异构化度较低。透射电镜显示共聚物在水中自组装形成球状胶束,直径随聚苯乙烯分子量的增加而增大。四、双羧基聚苯乙烯与DPA酰胺化反应得到双叔胺基聚苯乙烯（PSt）₂（N（CH₃）₂）₂,与三硫代碳酸酯羧酸衍生物（DMP）质子转移形成离子键超分子链转移剂（PSt）₂（DMP）₂,进行N-异丙基丙烯酰胺（NIPAM）的可逆加成断裂链转移（RAFT）聚合,得到超分子两亲性四杂臂共聚物,（PSt）₂（PNIPAM）₂,共聚物的臂长可以通过聚合时间调节。共聚物用¹H NMR、IR和GPC进行表征。离子键（PSt）₂（PNIPAM）₂在酸性条件下即可解离,解离下来PNIPAM用¹H NMR和GPC测定的分子量与理论值很接近,而且分子量分布很窄（M_w/M_n=1.05）,说明共聚物上PNIPAM链长很接近。五、考虑到离子键没有方向性,结合离子键和π-π相互作用构建缩聚型超分子聚合物。二萘嵌苯-3,4,9,10-四羧酸二酐（PTCDA）与DPA反应得到N,N-二（二甲胺基亚丙基）-3,4,9,10-茈二酰亚胺（BPTA-PDI）,BPTA-PDI与酒石酸（TTA）通过羧基与叔胺基的质子转移形成离子键超分子聚合物,BPTA-PDI/TTA。两种单体均有两个官能团,如同A2+B2型缩聚反应,形成线形聚合物。IR、¹H NMR对产物进行表征。我们用紫外、荧光、透射电镜和扫描电镜考察了BPTA-PDI/TTA在水和乙醇中的自组装行为。水溶液冷冻干燥样品的电镜照片显示了很长的带状纤维,纤维宽度大约100到480纳米,长达10微米以上。在乙醇中形成的一维带状纳米棒在尺寸上小的多,长度不足一微米,直径比较均一,约30纳米;而且纳米棒更加有规则。更多还原

【Abstract】 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.更多还原