Shape Memory Polymers and Their Applications to Smart Textile Products

A review is presented in this paper on Shape Memory Polymers (SMPs) and their applications to smart, particularly textile products. Different kinds of SMPs developed by researchers around the world, characteristics of SMPs and their applications, particularly to smart textiles are summarized. Current situations and potential application areas as well as future developments of smart textiles with shape memory polymers are discussed.

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.

An investigation on multilayer shape memory polymers under finite bending through nonlinear thermo-visco-hyperelasticity

This study presents a semi-analytical solution to describe the behavior of shape memory polymers(SMPs) based on the nonlinear thermo-visco-hyperelasticity which originates from the concepts of internal state variables and rational thermodynamics.This method is developed for the finite bending of multilayers in a dual-shape memory effect(SME) cycle.The layer number and layering order are investigated for two different SMPs and a hyperelastic material.In addition to the semi-analytical solution,the finite element simulation is performed to verify the predicted results,where the outcomes demonstrate the excellent accuracy of the proposed solution for predicting the behavior of the multilayer SMPs.Since this method has a much lower computational cost than the finite element method(FEM),it can be used as an effective tool to analyze the SMP behavior under different conditions,including different materials,different geometries,different layer numbers,and different layer arrangements.

Electroosmotic Water Vapor Transport across Novel, Smart, Functionalized Conducting Polymer Microporous Membranes in Active Mode at Very High Rates, with Concomitant Chemical Warfare (CW) Agent Blocking

Electroosmotic water vapor transport (WVT) across very thin, flexible, functionalized conducting polymer (CP) microporous (μP) membranes at a very high rate is reported. Both passive and active (6 VDC applied) WVT are reported, the latter for the first time ever. WVT occurs with concomitant, effective blocking of chemical warfare (CW) agents, again demonstrated for the first time ever. Initial active liquid||membrane||liquid interface studies demonstrated WVT rates of >1.7 × 10-5g .mm-2s-1, >3 × the highest prior reported values of 5 × 10-6g.mm-2s-1. Subsequent vapor||membrane|| vapor interface studies using industry-standard methods (including ASTM E96B Upright Cup (“WVT”), ASTM F2298 (“Dynamic Moisture Permeation Cell”) and ASTM F1868 (“Sweating Guard Hotplate”) were done at independent, external labs for independent corroboration. These yielded, e.g., WVT values of2564.4 g.m2.d-1 (passive) and3706.7 g.m2d-1 (active), to be compared with the highest (passive) value ever reported previously,984.8 g.m2.d-1 for a μP-Nylon membrane. More than 15 different membrane configurations, porosities and types were studied, including membranes with CP + organophosphate hydrolase (OPH), an enzyme reactive to CW agents. Efficient blocking of the actual CW agents GB, HD, VX is also reported, using the TOP-8-2-501standard. Membranes also passed all Industry-standard durability tests, e.g. ASTM D2261 (Tearing), ASTM D5034 (Breaking), ASTM D3886 (Abrasion), ASTM F392 (Gelbo Flex). Incorporation into smart soldiers’ garments was demonstrated;power consumption was -2. Mechanisms of enhanced WVT and CW agent blocking in the membranes are discussed.

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.

Polyelectrolyte complex-based thermochromic hydrogels containing carbonized polymer dots for smart windows with fast response,excellent solar modulation ability,and high durability

Thermochromic smart windows have gained increasing popularity in light modulation and energy management in buildings.However,the fabrication of flexible thermochromic smart windows with high luminous transmittance(Tlum),tailorable critical temperature(τc),strong solar modulation ability(ΔTsol),and long-term durability remains a huge challenge.In this study,hydrogel-based thermochromic smart windows are fabricated by sandwiching thermochromic hydrogels of polyallylamine hydrochloride,polyacrylic acid,and carbonized polymer dots(CPDs)complexes between two pieces of transparent substrates.Benefiting from the incorporation of nanosized CPDs,the thermochromic hydrogel has an ultrahigh Tlum of~98.7%,a desirableτc of~24.2℃,aΔTsol of~89.3%and a rapid transition time of~3 s from opaque state to transparent state.Moreover,the thermochromic hydrogel exhibits excellent anti-freezing ability,tight adhesion toward various substrates,and excellent self-healing capability.The self-healing capability enables the fabrication of large-area smart windows by welding multiple hydrogel pieces.The smart windows retain their original thermochromic properties after being stored under ambient conditions for at least 147 days or undergoing 10,000 uninterrupted heating/cooling cycles.The model houses with smart windows can achieve a temperature reduction of 9.2℃,demonstrating the excellent indoor temperature modulation performance of the smart windows.

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.

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℃.

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。

基于光栅动画图案合成光纤织物的设计及其实现

通过光栅原理将动态画面用于织物设计时,易出现织物的双层结构复杂、色彩难以精准控制等问题,提出基于光栅动画图案合成原理设计动态图案光纤织物,利用提花工艺将光纤和纱线织造成图案织物,使用发光二极管作为光源,通过热塑管将其分别与聚合物光纤耦合连接,利用发光控制器,使得二极管依次间隔发光,显示相邻动作的静态图案。还分析了合成图片个数、切分用光栅细度、分组发光频率等对图案动态效果的影响。以光纤和棉纱为原料,采用提花织机设计和织造聚合物光纤织物,结果表明:当以直径为0.25 mm的聚合物光纤作为最小发光单元时,5帧数合成的光纤发光织物能够同时兼顾动画呈现的识别度和流畅度;间隔条纹宽度在0.25 mm时,动态效果呈现时,物体轮廓越清晰;当发光频率为0.2 s时,其呈现的动态效果最好。该思路开拓了织物上动态图案呈现的全新实现方法。

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

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.

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.

低临界共溶温度可调聚氨酯的合成及温度响应性能研究

温度响应聚合物是一种重要的刺激响应智能材料,在诸多重要领域展现出了巨大的应用价值。本研究合成了一种在水中具有低临界共溶温度(LCST)的温度响应聚氨酯,可以通过向水体系中加入不同质量十二烷基苯磺酸钠(SDBS)的方式轻松、快速调整其LCST,而无需通过改变反应物中亲水链段和疏水链段的质量比来预先调节。文中同时探究了聚氨酯在水中的温度响应性能,结果表明SDBS可以提高聚氨酯疏水链段在水中的溶解性,防止相互聚集,因此SDBS含量越大,温度响应聚氨酯的LCST越高。

An Ion-imprinted Silica Gel Polymer Prepared by Surface Imprinting Technique Combined with Aqueous Solution Polymerization for Selective Adsorption of Ni(Ⅱ) from Aqueous Solution

A novel Ni（Ⅱ） ion-imprinted silica gel polymer was prepared via the surface imprinting technique combined with aqueous solution polymerization by using 2-acrylamido-2-methyl-1-propanesulfonic acid（AMPS） as a functional monomer for the selective separation of Ni（Ⅱ） from aqueous solution. The sorbent showed good chemical and thermal stability. Kinetics studies indicated that the equilibrium adsorption was achieved within 10 min and the adsorption kinetics fitted well with the pseudo-second-order kinetic model. The maximum adsorption capacity of the ion-imprinted polymer towards Ni（Ⅱ） at the optimal p H of 7.0 was 66.22 mg·g^（-1）. The relative selectivity coefficients of the sorbent were 9.23, 15.71, 14.72 and 20.15 for Ni（Ⅱ）/Co（Ⅱ）, Ni（Ⅱ）/Cu（Ⅱ）, Ni（Ⅱ）/Zn（Ⅱ） and Ni（Ⅱ）/Pb（Ⅱ）, respectively. The adsorption isotherm fitted well with Langmuir isotherm model. The thermodynamic results indicated that the adsorption of Ni（Ⅱ） was a spontaneous and endothermic process. The sorbent showed good reusability evidenced by six cycles of adsorption/desorption experiments. The precision of this method is satisfactory. Thus, the prepared sorbent can be considered as a promising sorbent for selective separation of Ni（Ⅱ） in real water samples.

Smart membranes for biomedical applications

Smart membranes with tunable permeability and selectivity have drawn widespread attention because of their unique biomimetic characteristics.Constructed by incorporating various stimuli-responsive materials into membrane substrates,smart membranes could self-adjust their physical/chemical properties(such as pore size and surface properties)in response to environmental signals such as temperature,pH,light,magnetic field,electric field,redox and specific ions/molecules.Such smart membranes show great prospects in biomedical applications ranging from controlled drug release to bioseparation and tissue engineering.In this review,three controlled release models realized by different designed smart membranes are emphatically introduced,and then smart membranes for biological separation and controlled cell culture are introduced and discussed respectively.At last,the existing challenges of smart membranes for biomedical applications are briefly summarized,and future research topics are suggested.

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.

响应形变液晶高分子的取向方法和功能开发

液晶高分子是同时具有液晶各向异性和高分子力学特性的功能高分子。在液晶高分子中引入具有光化学异构化或者光热响应的结构单元,可以使其在光或者热刺激下发生相转变,引发宏观形状变化。通过一步或两步的取向方法可以对液晶高分子中液晶基元的取向方向进行调控,实现材料的变形编程。液晶高分子形态上的变化在仿生软机器人、微流控、柔性执行器、结构色和防伪等领域有潜在的应用价值。本文介绍了液晶高分子主要的取向技术和开发出的基于形状变化的器件功能,并展望了液晶高分子形变材料在高新科技领域的应用前景。

考虑电网辅助服务的分布式能源聚合体优化方法

分布式能源个体一般无法直接参与电力市场交易或提供电网辅助服务,这可以通过分布式能源聚合来解决。在多能源类型、多交易市场及多服务基础上,提出一种新的分布式能源聚合体优化方法,该方法分为一级、二级、三级3个阶段的优化。首先,一级优化中使用了线性化技术来克服聚合体跨时空调度问题的非凸性,并将问题转换成混合整数线性规划问题,得出日前机组组合方案;其次,二级优化中基于一级优化给出的机组组合方案并使用最优潮流方程的二阶锥凸松弛求解经济调度问题以获得节点电压和功率流;然后,在三级优化中对偏离二级优化设定点进行惩罚,使三级优化接近系统最佳运行点,同时具有较短的规划范围;最后,在案例研究中将优化方法应用于一个包含电解制氢、风力发电及光伏发电等多能源聚合体模型。测试结果表明:所提出方法在电网辅助服务支持和聚合体灵活性增强方面的优势,并以最大限度增加运营收益,证明所提方法的有效性。

可切换润湿性超疏水表面制备方法及应用

目的制备可切换润湿性的智能超疏水表面,并探索该表面潜在的应用前景。方法利用模板法,基于热响应形状记忆聚合物(Shape Memory Polymer,SMP)制备具有条状微结构阵列的可切换润湿性智能超疏水表面,并对其润湿性可逆转换能力及循环使用稳定性进行测试。结果通过扫描电子显微镜观察到所制备表面微结构完整且轮廓清晰,液滴接触角在该表面可达到(150±3)°。通过加热使该表面达到玻璃化转变温度,此时对其施加外载荷使表面上条状微结构向一侧倾倒,由于微结构形态的改变,SMP表面疏水性减弱、水黏附性增强,再通过简单加热就可以使表面形态恢复至原始状态。通过试验测得环氧SMP的形状固定率为98.8%、形状回复率为96.3%,均达到95%以上,由于其优异的形状记忆特性,条状微结构的形态可以在原始直立状态和受到外载荷时的倾倒状态之间产生热响应而自由转变,且这种润湿性转换循环10次以上后,该表面依然保持着相对良好的润湿性可逆转换能力。结论基于形状记忆聚合物制备出的可切换润湿性智能超疏水表面具有良好的润湿性可逆转换能力和循环使用能力,且在液滴微反应器、生物检测、可重写液体图案、无损失液滴转移和芯片实验室设备中具有巨大的潜在应用前景。