A salt-induced viscosifying smart polymer for fracturing inter-salt shale oil reservoirs

Inter-salt shale oil reservoirs located between two salt layers are always accompanied by high temperature and high salinity. However, the present commonly used water-soluble polymers in fracturing fluids su er from poor tolerance to high temperature and high salinity. Thermoviscosifying polymers(TVP) whose aqueous solution shows viscosity increase upon increasing temperature and salt concentration have received considerable attention recently, which is promising for utilization in fracturing fluids to overcome these problems. In this work, both the salt-induced viscosifying property and mechanism of a TVP solution were investigated and the performance of TVP used as fracturing fluid based on the conditions of the Jianghan inter-salt shale oil reservoir in China was evaluated. It is found that the salt-induced viscosifying property of the TVP solution decreases with temperature and shear rate, but increases with polymer concentration. The number of intermolecular hydrophobic domains increases with the salt concentration contributing to the strengthening of a 3D network structure, which results in an increase in viscosity. In addition, the TVP fracturing fluid formulated with saturated brine exhibits excellent temperature and shear resistance, sand-suspending performance, and gel-breaking performance. Its viscosity remains above50 m Pa s after being sheared for 1 h even at a high temperature of 140 °C and the sand-suspending stability can be maintained for more than 1 week at 100 °C. Furthermore, the fracturing fluid can be easily broken down within 12h using 0.2 wt%–0.3 wt% potassium persulfate without residue.

Smart Polymers and Coatings Obtained by Ionizing Radiation: Synthesis and Biomedical Applications

Gamma radiation has been shown particularly useful for the functionalization of surfaces with stimuli-responsive polymers. This method involves the formation of active sites (free radicals) onto the polymeric backbone as a result of the exposition to high-energy radiation, in which a proper microenvironment for the reaction among monomer and/or polymer and the active sites takes place, thus leading to propagation which forms side chain grafts. The modification of polymers using high-energy irradiation may be performed by the following methods: direct or simultaneous, pre-irradiation oxidative and pre-irradiation. The most frequent ones correspond to the pre-irradiation oxidative method and the direct one. Radiation-grafting has many advantages over conventional methods considering that it does not require catalyst nor additives to initiate the reaction, and in general, no changes on the mechanical properties with respect to the pristine polymeric matrix are observed. This chapter focused on the synthesis of smart polymers and coatings obtained by the use of gamma radiation. In addition, diverse applications of these materials in the biomedical field are also reported.

Emission or scattering?Discriminating the origin of responsiveness in AIEgen-doped smart polymers using the TPE dye

Aggregation-induced emission(AIE)luminogens are attractive dyes to probe poly-mer properties that depend on changes in chain mobility and free volume.When embedded in polymers the restriction of intramolecular motion(RIM)can lead to their photoluminescence quantum yield(PLQY)strong enhancement if local microviscosity increases(lowering of chain mobility and free volume).Nonethe-less,measuring PLQY during stimuli,i.e.heat or mechanical stress,is technically challenging;thus,emission intensity is commonly used instead,assuming its direct correlation with the PLQY.Here,by usingfluorescence lifetime as an absolutefluorescence parameter,it is demonstrated that this assumption can be invalid in many commonly encountered conditions.To this aim,different poly-mers are loaded with tetraphenylenethylene(TPE)and characterized during the application of thermal and mechanical stress and physical aging.Under these con-ditions,polymer matrix transparency variation is observed,possibly due to local changes in refractive index and to the formation of microfractures.By combin-ing different characterization techniques,it is proved that scattering can affect the apparent emission intensity,while lifetime measurements can be used to ascertain whether the observed phenomenon is due to modifications of the photophysi-cal properties of AIE dyes(RIM effect)or to alterations in the matrix optical properties.

Smart polymers for the controlled delivery of drugs–a concise overview

Smart polymers have enormous potential in various applications.In particular,smart polymeric drug delivery systems have been explored as“intelligent”delivery systems able to release,at the appropriate time and site of action,entrapped drugs in response to specific physiological triggers.These polymers exhibit a non-linear response to a small stimulus leading to a macroscopic alteration in their structure/properties.The responses vary widely from swelling/contraction to disintegration.Synthesis of new polymers and crosslinkers with greater biocompatibility and better biodegradability would increase and enhance current applications.The most fascinating features of the smart polymers arise from their versatility and tunable sensitivity.The most significant weakness of all these external stimuli-sensitive polymers is slow response time.The versatility of polymer sources and their combinatorial synthesis make it possible to tune polymer sensitivity to a given stimulus within a narrow range.Development of smart polymer systems may lead to more accurate and programmable drug delivery.In this review,we discuss various mechanisms by which polymer systems are assembled in situ to form implanted devices for sustained release of therapeutic macromolecules,and we highlight various applications in the field of advanced drug delivery.

A comprehensive review of select smart polymeric and gel actuators for soft mechatronics and robotics applications:fundamentals,freeform fabrication,and motion control

Smart polymeric and gel actuators change shape or size in response to stimuli like electricity,heat,or light.These smart polymeric-and gel-based actuators are compliant and well suited for development of soft mechatronic and robotic devices.This paper provides a thorough review of select smart polymeric and gel actuator materials where an automated and freeform fabrication process,like 3D printing,is exploited to create custom shaped monolithic devices.In particular,the advantages and limitations,examples of applications,manufacturing and fabrication techniques,and methods for actuator control are discussed.Finally,a rigorous comparison and analysis of some of the advantages and limitations,as well as manufacturing processes,for these materials,are presented.

面向化学类非高分子专业学生的高分子化学实验教学创新与实践——以温敏型高分子的制备、溶液性质、光学性能与应用为例

面向化学类(非高分子)专业的高分子化学实验教学发展较为缓慢,亟需紧跟研究前沿,引入新内容。本文总结了近十年的教学改革经验,并以温敏型高分子的制备、溶液性质、光学性能与应用为例,介绍如何通过实验教学内容、实验技术、教学方法等方面的创新,设计符合理科人才培养需求的、契合时代与科学发展的、被学生喜爱与重视的一系列高分子化学实验,以有效解决培养需求与课业负担之间的矛盾,且在不新增开课、课时有限的情况下,加入到化学类专业本科教学体系中,激发学生对学科领域的兴趣,提升学生的探究和创新能力。

Polymers in Drug Delivery

Polymers are being used extensively in drug delivery due to their surface and bulk properties. They are being used in drug formulations and in drug delivery devices. These drug delivery devices may be in the form of implants for controlled drug delivery. Polymers used in colloidal drug carrier systems, consisting of small particles, show great advantage in drug delivery systems because of optimized drug loading and releasing property. Polymeric nano particulate systems are available in wide variety and have established chemistry. Non toxic, biodegradable and biocompatible polymers are available. Some nano particulate polymeric systems possess ability to cross blood brain barrier. They offer protection against chemical degradation. Smart polymers are responsive to atmospheric stimulus like change in temperature;pressure, pH etc. thus are extremely beneficial for targeted drug delivery. Some polymeric systems conjugated with antibodies/specific biomarkers help in detecting molecular targets specifically in cancers. Surface coating with thiolated PEG, Silica-PEG improves water solubility and photo stability. Surface modification of drug carriers e.g. attachment with PEG or dextran to the lipid bilayer increases their blood circulation time. Polymer drug conjugates such as Zoladex, Lupron Depot, On Caspar PEG intron are used in treatment of prostate cancer and lymphoblastic leukemia. Polymeric Drug Delivery systems are being utilized for controlled drug delivery assuring patient compliance.

电色smart窗

综述了电色smart窗的由来、设计准则、窗的基本结构。介绍了组成窗的各层膜特性，某些试制型窗的实例、还探讨了电色开关窗器件的耐久性问题。

Synthesis of Temperature- and pH-Sensitive Graft Copolymer Containing 2-(Diethylamino)ethyl Methacrylate and N-Vinylcaprolactam onto Silicone Rubber

Silicone rubber films were modified by the consecutive grafting of 2-(diethylamino)ethyl methacrylate (DEAEMA) and N-vinylcaprolactam (NVCL) using direct method on two steps with gamma-rays. The effect of absorbed dose and monomer concentration on grafting degree was determined. The grafted samples were verified by FTIR-ATR spectroscopy and swelling;thermal properties were analyzed by DSC and TGA. The stimuli-responsive behavior was studied by swelling and/or DSC. Thermo- and pH-sensitive films of (PP-g-DEAEMA)-g-NVCL presented a pH critical at 3.2 and LCST around 63.5℃.

Effect of CF and RPP on the Mechanical and Electrical Properties of Smart Aggregate

By using redispersible polymer powder（RPP） and carbon fiber（CF） to adjust the flexibility and electrical properties of the smart aggregate, a new kind of smart aggregate with Z type structure was proposed. The study shows that Z type aggregate is more sensitive to the feedback of external force than the prism aggregate in the same loading environment, and it indicates that Z type aggregate is more suitable for the research and application of concrete health monitoring. Although the incorporation of RPP would cause the compressive strength of the aggregates and the elastic modulus of hardened cement mortar to reduce slightly within the dosage of RPP by 2.25% because of the polymer film formed in the internal system, this would improve the deformability of the aggregates. In the early loading stage（in the first 60 seconds）, the intelligent concrete specimens implanted with Z type smart aggregate do not show higher sensitivity as expected, although the resistance change rate changes a little bit more, the overall of it is still in balance. Adding RPP could improve the flexibility of smart aggregates exactly, and it plays an active role in prolonging the life of the smart aggregates. By implanting Z type aggregates the damage and failure of the concrete structure could be predicted accurately in this study. The results of this paper will help to promote further research and application of intelligent concrete.

A Disulfide-Based Poly(ether-b-amide)Copolymer with Rapid Self-healing Ability under Moderate Conditions

Comprehensive Summary A disulfide-based poly(ether-b-amide)copolymer with rapid self-healing capability under moderate conditions was synthesized from 4,4’-dithiodibutyric acid(DTDBA),isophorondiamine(IPDA)and poly(tetramethylene oxide)(PTMO)based on a two-step method.The incorporation of IPDA with asymmetric structure and substantial steric hindrance not only effectively decreased the number of regular H-bonds,but also inhibited the crystallization of polyamide segments,imparting the synthesized poly(ether-b-amide)copolymer with an amorphous structural feature.Based on the coordination of segmental diffusion and recombination of disulfide bonds and hydrogen bonds,the scratches and damaged mechanical properties of PEBADS-I611 could be completely self-healed after healing at 40°C for only 11 min and 3 h,respectively.

智能电网通信安全多维数据聚合方法研究

文章针对当前聚合方法聚合时间成本高、聚合过程中数据泄露量大,影响智能电网通信运行效率和安全性的问题,提出智能电网通信安全多维数据聚合方法。将智能电表中的数据汇总,生成智能电网通信多维数据。将同态加密与椭圆曲线密码加密相结合,进行智能电网通信多维数据安全加密。对加密后的多维数据聚合,实现分析响应。通过实例证明,所提方法在实际应用中聚合时间成本有效降低,能够有效控制在聚合中数据的泄露,提高智能电网运行效率和安全性。

微胶囊自修复聚合物材料

对微胶囊自修复聚合物材料的修复机理、修复剂、催化剂及聚合物基体的选择等进行了阐述,并指出最新发展动态及未来发展趋势。

智能高分子开关膜的制备方法研究进展

智能高分子开关膜是将智能高分子与非刺激响应型基材膜结合而成。由于智能高分子能够响应外界刺激发生亲疏水性转变和构象变化,智能高分子开关膜也能根据外部刺激改变自身的表面/界面特性、渗透通量或选择透过性。智能高分子膜被用作抗污染滤膜、亲和分离、酶反应的起/停控制以及控制释放等。智能高分子开关膜的制备方法直接影响其环境刺激响应特性、稳定性和可重复制备性等。因此,系统介绍了基材膜修饰法、基材修饰成膜法和共混成膜法等3种智能高分子开关膜制备方法的定义、分类、机理和研究进展,并对比了3种方法的优缺点。基材膜修饰法研究最多,而共混成膜法最有望用于大规模制备智能高分子膜。本文以期为高效制备具有稳定、优良响应特性的智能高分子开关膜提供指导和参考。

面向云计算的智能电网数据安全策略研究

未来智能电网在为用户提供一个双向互动、高可靠性、高质量的电力服务的同时,也面临着用户隐私泄露、电网敏感数据加密等亟待解决的问题,文中首先分析了当前电网数据结构及特征,得出威胁电网数据安全的几个因素—密文数据访问、敏感数据获取以及完整性数据的测试问题。其次讨论了几项目前数据加密技术—对称、非对称加密、属性粒度加密,在论证了其在保护数据隐私安全方面的良好性能之后发现了中心服务器在数据处理方面的诸多瓶颈,如:服务器端不能对不同类型数据进行比较、划分,也无法实现投影操作,多表查询生成很多伪连接。综合上述弊端提出了基于盲签名的数据聚合策略,最后通过实验得出此策略在解决上述问题的同时实现了匿名性,且支持加法、非加法的高效保护机制,证明了该策略在保证智能电网数据安全方面的可行性。

智能涂料制备方法探索与应用

智能涂料是近几年在新型特种功能涂料基础上发展起来的。本文主要对其制备方法、类别及应用进行了详细论述。智能涂料的制备可以从聚合物膜、颜料及制作工艺等方面入手,其中创造具有"开关"性质且依赖于外部环境的刺激/响应聚合物膜的设计最为重要,它关系到膜的形成和膜表面性质,是涂料智能化的关键所在。在合成方法上,活性/可控自由基聚合技术、表面接枝技术和层层自组装工艺等已经应用于智能聚合物膜的制备;另外,纳米技术应用于涂料,也是智能涂料另一制备方法,因其某些超强性能而被视为智能涂料的初级阶段。目前,整个智能涂料的发展还基本处于以纳米技术为基础的初级阶段,其中进展较大的品种有:自清洁、抗菌、防腐、隐身、发光、磁性等对光、电、磁、温、湿、压敏感的涂料,而以智能聚合物膜为基础的高层次智能涂料还基本处于研究开发阶段。

聚合物胶束在药物传输系统中的应用

聚合物胶束作为纳米载体在药物的传输系统中具有广阔的应用前景。综述了聚合物胶束的结构和特点、聚合物胶束的形成过程及其稳定性,并结合研究的课题,阐述了以天然高分子(壳聚糖)为原料制备的接枝聚合物胶束的优势,及其作为药物载体的应用进展。

聚合物结构对PDLC性能的影响

用光聚合诱导相分离法制备了3种不同聚合物基体的聚合物分散液晶(PDLC)膜,研究了液晶含量和固化时间对PDLC透光率及膜形态的影响,考察了不同聚合物基体对PDLC电光性能的影响。结果表明,聚合物单体反应活性越高,达到关态下最低透过率所需的固化时间越短,丙烯酸仅需10 s,而甲基丙烯酸甲酯却需360 s;聚合物与液晶颗粒之间的相互作用越强,PDLC膜的阈值电压越高,丙烯酸的阈值电压至少是其他两者的5倍。

导电高分子电致变色智能热控器件(英文)

采用简单的旋涂、喷涂等方法,制备了一种由可溶性聚苯胺为主体电致变色智能热控器件。该器件的基底为聚酯,固体电解质为锂盐/聚丙烯腈。通过电切换调控,该器件发射率能够在0.46-0.75内调控,且红外光谱反射率变化大于38%。研究了厚度、预掺杂酸种类、浓度等对聚苯胺活性层发射特性的影响;考察了导电高分子聚苯胺层厚度、电切换电压等因素对涂层体系发射率调控的影响。结果表明发射率的调控范围与电化学还原的深度密切相关,通过调节材料厚度、掺杂酸种类等可有效提高发射率调控范围。该导电高分子电致变色智能热控涂层在航天器热控制方面展示了良好的应用前景。

基于18-冠-6的铅离子检测技术研究进展

铅是一种对环境和人体有严重危害的重金属污染物,研究铅离子(Pb^2+)检测技术具有重要的实用意义。近年来,利用18-冠-6的Pb^2+特异识别性能,研究者们设计构建了一系列智能高分子材料系统,为Pb^2+检测提供了新的策略和途径。本文综述了近年来基于18-冠-6的Pb^2+检测技术研究进展,重点介绍了基于智能膜、智能光学元件、智能微芯片、智能微胶囊等智能材料系统的Pb^2+检测技术,讨论了这些Pb^2+检测技术在实际应用中需要重点关注和解决的问题,以期为这类基于18-冠-6的Pb^2+检测技术的进一步开发和应用提供参考。