【作者】 李博；

【导师】 马宁；

【作者基本信息】 哈尔滨工程大学 ， 材料科学与工程， 2021， 博士

【摘要】 超分子化学利用非共价相互作用构筑功能结构的思想,为设计合成刺激响应性新材料提供了丰富的灵感和无限的可能性。通过将传统聚合物化学和新兴超分子化学的知识相结合,根据功能需求设计,获得明确的超分子结构并制备超分子聚合物材料,已成为功能材料领域的研究热点。无数科研人员在继续探究超分子相互作用的同时,全面开展超分子材料在电子信息、医疗健康、生物医药以及环境能源等领域的应用研究。本论文中,利用脲基嘧啶酮(2-ureido-4[1H]-pyrimidinone,UPy)基团四重氢键的动态可逆特性,构筑能够满足特定需求的响应性超分子聚合物材料,并将其应用于电子器件和医疗健康领域,为超分子聚合物材料的应用提供新的思路与策略。具体研究内容如下:为满足在低温潮湿和水环境中应用的电子器件快速自修复的需求,基于四重氢键UPy基团的动态可逆性及热响应性,设计合成两种不同熔融温度的主链型端UPy基超分子聚合物,利用超分子聚合物的稀溶液性将二者均匀混合,通过探究不同混合比例与自修复温度的关系,得到在室温条件下保持稳定力学性能,同时能够在人体掌心温度下(33-34℃)进行自修复的超分子聚合物材料。以此为基底,采用空气喷涂多壁碳纳米管(MWCNTs)三氯甲烷分散液的方法,快速地将MWCNTs“植入”表面溶解的基底中,获得兼具良好导电性和附着力的功能填料涂层。由此制备的MWCNTs/超分子聚合物薄膜,具有热敏感和力响应特性,可用作生理运动及生命体征监测设备的柔性传感器。同时超分子聚合物基底和MWCNTs的疏水性及MWCNTs的光热转换特性,使得复合材料薄膜传感器破损时,能够实现在水下环境中,通过7 m W/mm~2非接触式近红外光NIR驱动,在1.5 min内快速自修复。低温环境中的运动与温度监测应用对于水凝胶材料是巨大的挑战,同时为提高超分子聚合物复合材料柔性器件的透明度和美观性,以便更好的服务于人机交互领域,基于四重氢键UPy结构的动态特性,利用UPy衍生物作为扩链剂,合成聚合物主链含有UPy基团的类聚氨酯结构的超分子聚合物。通过主链PEG片段的亲水性,采用溶胀的方式,在体系中引入1-己基-3-甲基咪唑溴盐离子液体水溶液,得到抗冻型超分子聚合物离子液体水凝胶。此凝胶具备低电阻率(0.51 kΩ·cm)、高含水量(～86%)、高溶胀率(～485%)、高透明度(～98%)和良好的拉伸性能(～750%),并能够在-20℃环境下保持稳定而灵敏的温度和压力响应性。由此构筑的柔性传感监测设备,能够在冬季零下温度的户外环境中进行实时准确的生理运动行为监测。同时,通过自动化程序设计,建立触觉反馈控制系统,使负载超分子聚合物离子液体水凝胶传感器的智能机械手兼具抓取柔软易碎物品与准确分拣冷热物体的能力,在服务型机器人领域有较强的应用潜力。超分子聚合物水凝胶同样适用于生物医药领域。基于对UPy衍生物作为扩链剂结构的研究,将UPy基团引入聚合物侧链,合成侧链含有UPy基团的类聚氨酯结构的超分子聚合物,并通过主链PEG片段的亲水性采用溶胀的方式得到超分子聚合物水凝胶。由于主链PEG片段和侧链UPy基团的亲疏水差异,及UPy基团的热响应性,超分子聚合物水凝胶在升温过程中会发生相变行为,导致材料透明度明显下降,且体积收缩约10%。本文设计合成不同UPy侧基含量的聚合物并制备相应水凝胶,利用DSC、SAXS、WAXS等表征手段,系统研究该体系的相变机理,推测其由UPy基团热响应性导致分子聚集行为变化所引起。其中,含PEG(M_W≈1000)的超分子聚合物水凝胶在人体温度环境(37℃)下能够发生明显的相变现象,具备生物医用材料的潜在应用价值。将其用作生物敷料,选择四种药物进行负载和体外释放实验,结果表明,水凝胶材料在模拟人体体温环境中(37℃)药物累积释放量高于室温下(20℃)的累积释放量,药物载体凝胶相变行为对其有一定贡献作用。更多还原

【Abstract】 Based on supramolecular chemistry,the idea of utilizing non-covalent interactions to establish functional structures provides abundant inspiration and infinite possibilities for the design and synthesis of sophisticated stimuli-responsive materials.Combining the knowledge of traditional polymer chemistry and emerging supramolecular chemistry,depending on the requirements of multiple functions,the designing and preparing of supramolecular polymer materials and attaining well-defined supramolecular structures have been a research hotspot in the field of functional materials.Numerous researchers focus on exploring supramolecular interactions,while simultaneously advancing the application and development of supramolecular materials science in the fields of electronics,healthcare devices,biomedicine,environment and energy.In this research,the prominent dynamic reversible 2-ureido-4[1H]-pyrimidinone（UPy）quadruple hydrogen-bonding motif was employed to construct responsive supramolecular polymer materials that can meet specific needs and promote them to electronic devices and medical and health fields.The main research contents are as follows:According to the application in the low temperature and underwater environment of the electronic device with fast self-healing properties,the dynamic reversible and thermal responsive UPy units were used to synthesize two kinds of supramolecular polymers with different T_m.Based on their dilute solution property,the mixture of supramolecular polymer was obtained.Studying the relationship between the different mixing proportion and self-healing temperature,a novel supramolecular polymer material（SPM）,which maintained a good mechanical property at room temperature and represented self-healing behavior in low temperature（33-34℃）,was finally obtained.Multi-walled carbon nanotubes（MWCNTs）were"implanted"into the SPM substrate as a functional coating by using air spraying method of MWCNTs/CHCl₃ dispersion,which endows the SPM film with a good conductivity,photo-thermal conversion and adhesion.The thermal and mechanical responsive flexible sensors were fabricated by the MWCNTs/SPM films,which were used as physiological motion and vital signs monitoring equipment.Due to the hydrophobicity of the SPM matrixes and MWCNTs,the sensor exhibited highly efficient self-healing properties in underwater environments by non-contact NIR actuation.It is challenging to prepare the hydrogel devoted to fabricate a form of multi-responsive skin-like sensor piggybacked on the tactile controlled robot which could grab the soft and fragile items at subzero temperatures.The supramolecular ionic liquid hydrogel,wherein ureidopyrimidinone（UPy）containing hydrophilic polyurethane（PU）was employed as networks and aqueous solutions of imidazolium ionic liquid acted as free phase.Combining the advantages of hydrophilic PEG segments,the hydrophobic UPy moieties,and the imidazolium ionic liquid,this supramolecular hydrogel exhibited high water content（～86%）,swelling ratios（～485%）,elongation（～750%）,low resistivity（0.51 kΩ·cm）and excellent transparency（～98%）.Moreover,the most striking characteristic was that the supramolecular hydrogel maintained its outstanding mechanical and thermal sensitivity at subzero temperatures such as-20℃.The supramolecular ionic liquid hydrogel was utilized to fabricate E-skin for intelligent robots to realize pressure feedback and thermal recognition.This line of research not only demonstrates that the anti-freezing stimuli-responsive hydrogel is a promising candidate for E-skins used in harsh conditions,but also contributes to the design and application of supramolecular polymers-based hydrogel sensors for future artificial intelligence applications.Based on the above,UPy derivatives,as chain extenders,were introduced into the side chain to structure supramolecular polymer.Through the hydrophilic PEG segments in main chain,the supramolecular polymer matrixes were swelled into hydrogel.Meanwhile,due to the hydrophilic and hydrophobic differences between the main chain PEG segments and the side chain UPy units,as well as t thermal-responsiveness of UPy groups,the supramolecular polymer hydrogel（SPH）represented phase transition during heating,which resulted in the material’s color whitening and volume shrinkage in macroscopic view.In this study,the mechanism of phase transformation in the system was investigated in detail.It is indicated SPH with PEG（M_W≈1000）had an obvious phase transition temperature close to the physiological temperature of the human body,which has vast potential application value of biomedical materials.Utilizing SPH as bio-dressings,the drug loading and in vitro release experiments were carried out demonstrating that the cumulative drug release in simulated human body temperature environment（37℃）was higher than that at room temperature（20℃）,and the phase transformation behavior of SPH drugs carrier partly contributed to it.更多还原