刺激响应型树状分子凝胶的研究进展※

近年来, 刺激响应型超分子凝胶作为一类智能软物质材料, 在离子识别材料、自修复材料、生物材料和药物缓释等领域展现出了非常好的应用前景, 受到人们广泛关注. 树状分子是一类具有高度支化结构的大分子, 其形成的凝胶兼具有机小分子凝胶和聚合物凝胶的双重优点, 树状分子丰富的多层次支化几何结构有利于修饰不同功能基团, 从而确保各功能基团彼此独立作用而不相互干扰, 这种特性使其在构筑多功能化凝胶材料, 尤其是多重环境刺激响应型凝胶材料方面具有独特优势. 基于此, 本综述从树状分子凝胶因子设计、成凝胶机理、响应性能和响应机理等方面详细归纳了刺激响应型树状分子凝胶的研究进展. 按照刺激源不同, 主要从光响应型、氧化还原响应型、离子响应型、触变响应型和多重响应型五个方面对刺激响应树状分子凝胶进行了系统归纳总结. 最后, 基于目前刺激响应树状分子凝胶存在的一些问题对该领域未来发展进行了展望.     

刺激响应型超分子凝胶

随着超分子化学的日益发展,刺激响应型超分子凝胶作为一种超分子材料受到人们广泛关注。超分子凝胶是由非共价键作用力自组装而成,基于这一特性,当超分子凝胶受到外界刺激（如温度、光、pH、化学物质、机械力等）时,该凝胶能够产生响应,如溶胶-凝胶转化、颜色变化或荧光变化等。刺激响应型超分子凝胶在离子识别材料、自修复材料、生物材料等领域展现出了非常好的应用前景。本文综述了近五年来刺激响应型超分子凝胶的研究进展,并根据刺激种类的不同,将超分子凝胶分为以下几类：热敏感型超分子凝胶、化学物质和pH响应型超分子凝胶、光敏感型超分子凝胶、氧化还原响应型超分子凝胶、机械力刺激响应型超分子凝胶和多重刺激响应型超分子凝胶。本文根据上述分类对超分子凝胶进行了介绍,同时对该研究领域作了展望。     

刺激响应型有机小分子凝胶的研究进展

智能型凝胶是近年来有机小分子凝胶的研究重点, 其中刺激响应型有机小分子智能凝胶对外界微小的物理、化学刺激, 如温度、光、pH、离子强度或电场等能够感知并在响应过程中有显著的响应行为性. 较系统地综述了刺激响应型有机小分子智能凝胶的结构特点和近年来的研究进展, 并展望了该类有机小分子智能凝胶的应用前景.     

基于苯硼酸的树枝状凝胶及其刺激响应

具有葡萄糖识别性质的超分子凝胶体系在医学诊断领域具有广泛的应用前景。本文通过简单的缩合反应成功构筑了基于苯硼酸和聚芳醚单元的树枝状凝胶因子,其结构利用核磁共振谱和质谱进行了表征。研究了该凝胶因子的凝胶化能力,利用UV-Vis、SEM和SAXS研究了其自组装机理和形貌。构筑的凝胶对热、酸碱和D-葡萄糖表现出多重刺激响应行为。本研究为构筑具有多功能性的软材料提供了一定的理论研究基础。     

刺激响应降解型聚合物水凝胶

作为一类重要的高分子材料,聚合物水凝胶由于其优良的理化性能和生物学特性而被广泛应用于生物医药领域,降解特性是其作为生物医用材料的重要性能指标。刺激响应降解型水凝胶是指在环境因素刺激下凝胶网络发生响应性断裂,进而产生凝胶-溶胶或溶胀-降解转变的一类智能高分子材料。这一响应降解特性可通过将环境敏感性断裂基团引入到聚合物凝胶网络中来实现。与水凝胶常规的水解、酶解相比,刺激响应降解因具有空间或时间上的可控特性而引起人们的广泛关注。本文重点介绍了pH响应、光响应以及氧化还原响应降解型聚合物水凝胶的设计方法、降解机理及其最新研究进展,并对刺激响应降解型水凝胶未来的研究方向进行了展望。     

刺激响应性水凝胶在肿瘤治疗中的研究进展

恶性肿瘤的治疗在临床中一直备受关注,由于肿瘤细胞的浸润性和顽固性,常规治疗通常会产生严重的毒副作用。相较于全身化疗,局部载药水凝胶的使用显著降低了全身毒性并可实现药物在肿瘤部位的持续递送。此外,经物理掺杂或化学修饰的刺激响应性水凝胶,还可响应环境条件变化(如温度、pH、光等),实现原位交联和药物可控释放,大大提高了临床顺应性和药物递送效率。本综述分类讨论了用于肿瘤治疗的刺激响应性水凝胶的设计策略;汇总了近年来此类水凝胶的研究进展及其药物递送方案;并针对该领域存在的实际问题提出了可能的发展方向。     

基于主客体作用的多重刺激响应型超分子水凝胶的制备及性能

利用单-6-脱氧-6-氨基-β-环糊精(β-CDNH2)与双二茂铁亚甲基丁二胺季铵盐(FBI)之间的主-客体作用制备了一种性能特异的超分子水凝胶, 该水凝胶具有显著的热可逆性和pH刺激响应性, (NH4)2Ce(NO3)6的引入导致凝胶液化, 体系的颜色也由淡黄色转变为墨绿色. 扫描电镜结果表明, 在凝胶中胶凝剂β-CDNH2和FBI结合组成以带状纤维为特征的三维网络结构. 1H NMR, FTIR, XRD以及循环伏安等表征结果表明, FBI与β-CDNH2间的主客体包结作用和β-CDNH2分子间的氢键作用是凝胶形成并能稳定存在的主要原因.     

智能纳米水凝胶的刺激响应性研究进展

智能纳米水凝胶在药物输送与可控释放、医学诊断、生物传感器、微反应器、催化剂载体等方面有良好的应用前景。结合本课题组近年来的研究成果,分别介绍了具有温度刺激响应性、pH刺激响应性、光刺激响应性、磁场刺激响应性、分子识别刺激响应性和多重刺激响应性智能纳米水凝胶的研究进展。另外,对这几种智能纳米水凝胶目前存在的问题和今后的发展方向提出了一些粗浅的看法。     

胆固醇分子印迹的聚合有机凝胶及其吸附性能研究

报道了一种新型胆固醇分子印迹的聚合有机凝胶.以3-胆固醇酰氧基丙酸(COPA)为模板分子,通过可聚合凝胶剂N-十八烷基马来酰胺酸(ODMA)在甲基丙烯酸β-羟乙酯、甲基丙烯酸和聚乙二醇二甲基丙烯酸酯混合溶液的自组装,首先形成稳定的超分子有机凝胶,经UV光引发原位聚合,再经乙醇提取模板分子后制得胆固醇非共价印迹的聚合有机凝胶.偏光显微镜(POM)和场发射扫描电镜(FE-SEM)表明ODMA在单体混合物中自组装形成带状聚集体,这为其后形成的印迹聚合有机凝胶的孔穴稳定性提供了保证.印迹聚合有机凝胶对胆固醇的吸附效率可达到64%,并与ODMA和COPA的含量有关.实验表明,当ODMA的含量由1wt%增加到3 wt%时,吸附量由15.7 mg/g增加到22.9 mg/g.当COPA的含量由4 wt%增加到7 wt%时,吸附量由16.8 mg/g增加到22.2 mg/g.然而,当ODMA含量过多时,吸附量反而下降,这主要归因于体系网络密度的增加导致扩散阻力增加.而COPA含量过多时,可能干扰ODMA的自组装,影响印迹孔穴的稳定性,同样使得吸附量下降.     

胆固醇分子印迹聚合有机凝胶的制备及其选择性吸附研究

以N-十八烷基马来酰胺酸(ODMA)为凝胶剂,在甲基丙烯酸β-羟乙酯、甲基丙烯酸、聚乙二醇二甲基丙烯酸酯和模板分子3-胆固醇酰氧基丙酸(COPA)混合物中自组装形成稳定的超分子有机凝胶,经UV原位光聚合,乙腈提取模板分子制备了胆固醇非共价印迹聚合有机凝胶.吸附实验在水/THF中进行.结果显示胆固醇非共价印迹聚合有机凝胶...     

树枝状醚酰胺多官能团(甲基)丙烯酸酯低聚物的合成及其紫外光固化性能的研究

合成了树枝状(甲基)丙烯酸化醚酰胺低聚物,采用拉曼光谱、光-差热分析和动态力学热分析方法对其紫外光固化动力学和固化膜热机械性能进行了研究.结果表明,这种树枝状低聚物在紫外光照下双键转化率可达80%以上,且其最大反应速率、固化膜的软化温度和玻璃化转变温度随双键浓度的增大而提高.     

Synthesis and Evaluation of Thermal Properties of Fluorinated Poly(aryl ether) Dendritic Structures Based on Calix[4]arenes

By using a convergence approach two new poly(aryl ether) dendritic structures carrying 4-fluorobenzyl bromide on the surface and calix[4]arenes as a core with G1 were synthesized for the first time. Fluorinated dendritic structures are connected through ether bonds on the lower rim of the calix[4]arene unit. Its structure was determined by ¹H-NMR and elemental analysis. The thermal stabilities of fluorinated dendritic structures, based on calix[4]arenes, were investigated using thermogravimetric analysis. The activation energies and thermal degradation of the structures were calculated with the Ozawa Method.     

Quinoline-cored Poly(Aryl Ether) Dendritic Organogels with Multiple Stimuli-Responsive and Adsorptive Properties

Functional supramolecular gel materials have potential applications in sensors, optical switches, artificial antennae, drug delivery and so on. In this paper, quinoline-cored poly(aryl ether) dendritic organogelators were designed, synthesized and fully characterized. The gelation behaviour of the dendritic organogelator was tested in organic solvents, mixed solvents and ionic liquids. The dendron Q-G1 was found to be an efficient and versatile organogelator toward various apolar and polar organic solvents with the critical gelation concentrations (CGCs) approaching 1.2×10^?2 mol/L, indicating one dendritic organogelator could immobilize 1.2×10³ solvent molecules in the organogel network. Interestingly, these dendrons exhibited excellent gel formation in ionic liquids. Notably, these dendritic organogels were found to display multiple stimuli-responsive properties toward external stimuli including heat, ultrasound and shear stress, with a reversible sol-gel phase transition. In addition, the dendritic organogel could effectively adsorb heavy metals and organic dyes. The removal rate of Pb²⁺ was up to 20% and the adsorption rate for Rhodamine B was as high as 89%.     

Fluorophore-labeled Polyamidoamine (PAMAM) Dendritic Architectures: Synthesis and Fluorescence Sensing Properties

Novel polyamidoamine (PAMAM) dendrimers (G=0.5–2.5) with a naphthalene core unit have been prepared. They were found to display acid as well as metal ion sensitive fluorescence signal amplification, making them of potential use as chemosensing materials. PAMAM dendritic wedges as well as naphthalene-centered PAMAM dendrimers were characterized by FT-IR, ¹H and ¹³C NMR spectroscopic methods and elemental analysis.     

金属离子对咔唑修饰的芳醚树枝形聚合物的荧光猝灭作用

合成了一系列外围带有咔唑, 核心带有或不带有氮杂冠醚结构的1-3代芳醚树枝形聚合物(CZ-Gn-CR, CZ-Gn-OH, n=1-3). 利用光物理方法研究了金属离子Li+、Na+、K+、Ca2+、Cu2+、Zn2+、Eu3+和Tb3+与树枝形聚合物之间的相互作用. 研究表明, Eu3+、Tb3+和Cu2+通过静态过程猝灭树枝形聚合物的荧光, 测定了Eu3+、Tb3+和Cu2+对CZ-Gn-CR、CZ-Gn-OH荧光的猝灭速率常数; 核心的冠醚结构可以增强树枝形聚合物与金属离子的相互作用. Li+、Na+、K+、Ca2+和Zn2+对CZ-Gn-CR和CZ-Gn-OH的紫外吸收光谱和荧光光谱均没有明显影响.     

Poly(benzyl ether) dendrimers with strongly fluorescent distyrylbenzene cores as the fluorophores for peroxyoxalate chemiluminescence: insulating effect of dendritic structures on fluorescent sites

Poly(benzyl ether) dendrimers containing strongly fluorescent distyrylbenzene cores were synthesized, and their fluorescence and electrochemical properties as well as the action as fluorophores in the chemiluminescence reactions were investigated. While all the dendrimers exhibited almost the same properties except for their intensities, a characteristic feature due to the dendritic structure was observed in the electrochemical behaviors. In the peroxyoxalate chemiluminescence reactions using these dendrimers as fluorophores, a bimolecular interaction between the high-energy intermediates and fluorophores was established, and a decrease in the chemiluminescence intensity with an increasing generation was observed, which was connected with the insulating effect of the dendritic structures on the core.     

聚醚砜醚酮的合成与性能

以4,4′-二羟基二苯砜和4,4′-二氟二苯酮为单体, 通过溶液缩聚合成了聚醚砜醚酮(PESEK), 其分子结构相当于聚醚砜(PES)与聚醚醚酮(PEEK)的交替共聚物. 在共聚物分子中, 存在砜基、醚基和酮基, 整个结构单元形成了大共轭体系, 聚合物属无定形聚合物, 玻璃化转变温度(Tg)为198 ℃, 介于PEEK和PES的Tg之间, 其热稳定性和加工性能优于PES, 而力学性能与PES接近.     

含三苯基膦聚醚醚酮酮的结构与性能

以双[4-(对氟苯甲酰基)苯基]苯基氧化膦和对苯二酚(HQ)为单体, 合成了新型主链含三苯基膦结构的聚醚醚酮酮, 并对聚合物的结构和性能进行了表征.     

A Pronounced Halogen Effect on the Organogelation Properties of Peripherally Halogen Functionalized Poly(benzyl ether) Dendrons

An interesting halogen‐substituent effect on the organogelation properties of poly(benzyl ether) dendrons is reported. A new class of poly(benzyl ether) dendrons with halo substituents decorating their periphery was synthesized and fully characterized. A systematic study on the gelation abilities, thermotropic behaviors, aggregated microstructures, and mechanical properties of self‐assembled organogels was performed to elucidate the halogen‐substituent effects on their organogelation propensity. It was found that the exact halogen substitutions on the periphery of dendrons exert a profound effect on the organogelation propensity, and dendrons G _n ‐Cl (n=2, 3) and G₂‐I proved to be highly efficient organogelators. The cooperation of multiple π–π, dispersive halogen, CH–π, and weak C?H ??? X hydrogen‐bonding interactions were found to be the key contributor to forming the self‐assembled gels. Dendritic organogels formed from G _n ‐Cl (n=2, 3) in 1,2‐dichloroethane exhibited thixotropic‐responsive properties, and such thixotropic organogels are promising materials for future research and applications.     

主链含酰亚胺结构的聚醚醚酮的合成及其性能

以1,4-二苯氧基苯为单体分别与N,N′-(4,4′-二苯甲烷)-双-(3,4-二甲酰亚胺基苯甲酰氯)和N,N′-(4,4′-二苯砜)-双-(3,4-二甲酰亚胺基苯甲酰氯),采用低温溶液缩聚合成了2种主链含酰亚胺结构的聚醚醚酮树脂,聚合物的比浓对数粘度分别为0.98和0.61 dL/g。 用FT-IR、¹H NMR和WAXD进行了结构表征,用DSC和TGA测试了热性能。 结果表明,聚合物有较高的玻璃化转变温度(T_g分别为236和263 ℃),N₂气气氛中热分解温度(5%T_d)分别为529和512 ℃,能溶于N,N-二甲基乙酰胺、N-甲基-2-吡咯烷酮、氯仿和间甲酚等常见的有机溶剂中。