IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2025-02-01 DOI: 10.1016/j.giant.2024.100349

Hong Li , Weiyi Jin , Weiyu Zhang , Jie Li , Jiaqi Ji , Yi Tang , Tianqi Yang , Shujiang Zhang , Haixia Yang , Chenliang Gong

Low-dielectric, transparent, and high-heat-resistant polyimide (PI) films are vital for flexible electronics and high-frequency communication devices. However, balancing these properties within intrinsic polyimides remains a significant challenge. In this work, a nonplanar diamine monomer, 2,7-bis(3,5-bis(trifluoromethyl)phenyl)-9,9-bis(4-nitrophenyl)-9H-fluorene (BTFDA), containing a Cardo structure and four trifluoromethyl groups, was synthesized and copolymerized with commercial monomers to produce a series of polyimides (CPI-X). These CPI-X exhibit exceptional heat resistance, with glass transition temperatures (T_g) exceeding 350 °C, decomposition temperatures (T_{d5 %}) above 530 °C, and low thermal expansion coefficients (CTE < 20.8 ppm/K). Additionally, they have excellent optical properties with over 92 % transparency at 450 nm and low birefringence (Δn = 0.00042). They also demonstrate good hydrophobicity with low water absorption (M_a% = 0.04 %) and high-water contact angles (C_a = 97.6°). Most importantly, the CPI-X films show excellent dielectric properties (D_k = 2.25, D_f = 0.00365 at 1 MHz, D_k = 2.13, D_f = 0.0065 at 10 GHz). Such intrinsic PI films with low D_k values may be ideal candidates for next-generation interlayer media.

低介电、透明和高耐热聚酰亚胺（PI）薄膜对于柔性电子和高频通信设备至关重要。然而，在固有聚酰亚胺中平衡这些特性仍然是一个重大挑战。本文合成了含有Cardo结构和4个三氟甲基的非平面二胺单体2,7-二（3,5-二（三氟甲基）苯基）-9,9-二（4-硝基苯基）- 9h -芴（BTFDA），并与商业单体共聚制备了一系列聚酰亚胺（CPI-X）。这些CPI-X具有优异的耐热性，玻璃化转变温度（Tg）超过350°C，分解温度（td5%）超过530°C，热膨胀系数(CTE <；20.8 ppm / K)。此外，它们具有优异的光学性能，在450 nm处具有超过92%的透明度和低双折射（Δn = 0.00042）。它们具有较低的吸水率（Ma% = 0.04%）和较高的水接触角（Ca = 97.6°），具有良好的疏水性。最重要的是，CPI-X薄膜表现出优异的介电性能（在1 MHz时Dk = 2.25, Df = 0.00365，在10 GHz时Dk = 2.13, Df = 0.0065）。这种具有低Dk值的本征PI薄膜可能是下一代层间介质的理想候选者。

{"title":"Intrinsic low-dielectric Cardo polyimide with high heat resistance, high transparency, and low birefringence","authors":"Hong Li , Weiyi Jin , Weiyu Zhang , Jie Li , Jiaqi Ji , Yi Tang , Tianqi Yang , Shujiang Zhang , Haixia Yang , Chenliang Gong","doi":"10.1016/j.giant.2024.100349","DOIUrl":"10.1016/j.giant.2024.100349","url":null,"abstract":"<div><div>Low-dielectric, transparent, and high-heat-resistant polyimide (PI) films are vital for flexible electronics and high-frequency communication devices. However, balancing these properties within intrinsic polyimides remains a significant challenge. In this work, a nonplanar diamine monomer, 2,7-bis(3,5-bis(trifluoromethyl)phenyl)-9,9-bis(4-nitrophenyl)-9H-fluorene (BTFDA), containing a Cardo structure and four trifluoromethyl groups, was synthesized and copolymerized with commercial monomers to produce a series of polyimides (CPI-X). These CPI-X exhibit exceptional heat resistance, with glass transition temperatures (<em>T</em><sub>g</sub>) exceeding 350 °C, decomposition temperatures (<em>T</em><sub>d5 %</sub>) above 530 °C, and low thermal expansion coefficients (CTE < 20.8 ppm/K). Additionally, they have excellent optical properties with over 92 % transparency at 450 nm and low birefringence (Δ<em>n</em> = 0.00042). They also demonstrate good hydrophobicity with low water absorption (<em>M</em><sub>a</sub>% = 0.04 %) and high-water contact angles (<em>C</em><sub>a</sub> = 97.6°). Most importantly, the CPI-X films show excellent dielectric properties (<em>D<sub>k</sub></em> = 2.25, <em>D<sub>f</sub></em> = 0.00365 at 1 MHz, <em>D<sub>k</sub></em> = 2.13, <em>D<sub>f</sub></em> = 0.0065 at 10 GHz). Such intrinsic PI films with low <em>D</em><sub>k</sub> values may be ideal candidates for next-generation interlayer media.</div></div>","PeriodicalId":34151,"journal":{"name":"GIANT","volume":"21 ","pages":"Article 100349"},"PeriodicalIF":5.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143098492","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Thermosensitive ferulic acid-modified chitosan gel coatings loaded with selenium nanoparticles for enhanced grape foliar rainfastness and selenium uptake 热敏阿魏酸修饰壳聚糖凝胶涂层负载纳米硒增强葡萄叶片耐雨性和硒吸收

IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2025-02-01 DOI: 10.1016/j.giant.2024.100351

Songpo Duan , Xin Ouyang , Yingsheng Liu , Dingyi Shen , Zhiming Li , Sijie Song , Hong Shen

Traditional Se (selenium) fertilizers are poorly deposited on crop leaves and are easily washed away by rain; these factors limit plant Se absorption and pose potential environmental risks. To address this issue, a thermosensitive Se nanoparticles gel (CS-FA/BP-SeNPs) based on chitosan-ferulic acid (CS-FA) and β-glycerophosphate (β-BP) was developed to increase rain-washing resistance and Se uptake in grape leaves. The CS-FA derivative was synthesized via an amide reaction between chitosan and ferulic acid_(1:2); this derivative demonstrated strong antibacterial and antioxidant activity, effectively dispersing the Se nanoparticles (SeNPs) and preventing their aggregation. β-glycerophosphate neutralized the pH value of the CS-FA/SeNPs solution, significantly increasing the stability of the SeNPs (stable for 30 days). Up to 37 °C, the solution rapidly formed a hydrogel, increasing its viscous modulus by 5.1 times and improving adhesion. Compared with SeNPs alone, CS-FA/BP-SeNPs showed superior spreading, reducing droplet splashing and retraction. In simulated rainfall experiments, the CS-FA/BP-SeNPs gel coating retained 91.1 % of the material on the leaf surface, while the corresponding value for SeNPs was 13.6 %, demonstrating excellent rainfastness in the former. In open-field cultivation trials, grape leaves treated with the CS-FA/BP-SeNPs gel coating presented a 141.3–192.7 % increase in the Se retention rate and a 51.3–62.3 % increase in Se uptake than those with SeNPs alone. Additionally, CS-FA/BP-SeNPs significantly reduced Fusarium oxysporum infection rates, demonstrating potential for use in challenging outdoor environments. This thermosensitive gel coating provides an effective strategy for enhancing nanoselenium utilization on crop leaves through its temperature-responsive properties and strong postgelation adhesion.

传统的硒肥料不能很好地附着在作物叶片上，而且很容易被雨水冲走；这些因素限制了植物对硒的吸收，造成了潜在的环境风险。为了解决这一问题，研制了一种基于壳聚糖阿魏酸（CS-FA）和β-甘油磷酸酯（β-BP）的热敏硒纳米凝胶（CS-FA/BP-SeNPs），以提高葡萄叶片的抗雨洗性和硒吸收能力。采用壳聚糖与阿魏酸（1:2）酰胺反应合成CS-FA衍生物；该衍生物具有较强的抗菌和抗氧化活性，能有效分散硒纳米粒子（SeNPs）并防止其聚集。β-甘油磷酸酯中和了CS-FA/SeNPs溶液的pH值，显著提高了SeNPs的稳定性（稳定30天）。当温度达到37℃时，溶液迅速形成水凝胶，黏性模量提高5.1倍，附着力提高。与单独使用SeNPs相比，CS-FA/BP-SeNPs具有更好的扩散，减少液滴飞溅和缩回。在模拟降雨实验中，CS-FA/BP-SeNPs凝胶涂层在叶片表面的材料保留率为91.1%，而SeNPs的保留率为13.6%，表明CS-FA/BP-SeNPs凝胶涂层具有优异的耐雨性。在露天栽培试验中，CS-FA/BP-SeNPs凝胶包膜处理的葡萄叶片硒保持率比单独处理的葡萄叶片高141.3 ~ 192.7%，硒吸收率比单独处理的葡萄叶片高51.3 ~ 62.3%。此外，CS-FA/BP-SeNPs显著降低了尖孢镰刀菌的感染率，显示了在具有挑战性的室外环境中使用的潜力。这种热敏凝胶涂层通过其温度响应特性和强大的凝胶后粘附性，为提高纳米硒在作物叶片上的利用提供了有效的策略。

{"title":"Thermosensitive ferulic acid-modified chitosan gel coatings loaded with selenium nanoparticles for enhanced grape foliar rainfastness and selenium uptake","authors":"Songpo Duan , Xin Ouyang , Yingsheng Liu , Dingyi Shen , Zhiming Li , Sijie Song , Hong Shen","doi":"10.1016/j.giant.2024.100351","DOIUrl":"10.1016/j.giant.2024.100351","url":null,"abstract":"<div><div>Traditional Se (selenium) fertilizers are poorly deposited on crop leaves and are easily washed away by rain; these factors limit plant Se absorption and pose potential environmental risks. To address this issue, a thermosensitive Se nanoparticles gel (CS-FA/BP-SeNPs) based on chitosan-ferulic acid (CS-FA) and <strong>β</strong>-glycerophosphate (<strong>β</strong>-BP) was developed to increase rain-washing resistance and Se uptake in grape leaves. The CS-FA derivative was synthesized via an amide reaction between chitosan and ferulic acid<sub>(1:2)</sub>; this derivative demonstrated strong antibacterial and antioxidant activity, effectively dispersing the Se nanoparticles (SeNPs) and preventing their aggregation. <strong>β</strong>-glycerophosphate neutralized the pH value of the CS-FA/SeNPs solution, significantly increasing the stability of the SeNPs (stable for 30 days). Up to 37 °C, the solution rapidly formed a hydrogel, increasing its viscous modulus by 5.1 times and improving adhesion. Compared with SeNPs alone, CS-FA/BP-SeNPs showed superior spreading, reducing droplet splashing and retraction. In simulated rainfall experiments, the CS-FA/BP-SeNPs gel coating retained 91.1 % of the material on the leaf surface, while the corresponding value for SeNPs was 13.6 %, demonstrating excellent rainfastness in the former. In open-field cultivation trials, grape leaves treated with the CS-FA/BP-SeNPs gel coating presented a 141.3–192.7 % increase in the Se retention rate and a 51.3–62.3 % increase in Se uptake than those with SeNPs alone. Additionally, CS-FA/BP-SeNPs significantly reduced <em>Fusarium oxysporum</em> infection rates, demonstrating potential for use in challenging outdoor environments. This thermosensitive gel coating provides an effective strategy for enhancing nanoselenium utilization on crop leaves through its temperature-responsive properties and strong postgelation adhesion.</div></div>","PeriodicalId":34151,"journal":{"name":"GIANT","volume":"21 ","pages":"Article 100351"},"PeriodicalIF":5.4,"publicationDate":"2025-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143099038","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Ions in motion: From biological channels to engineered transport systems 运动中的离子：从生物通道到工程运输系统

IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2025-01-15 DOI: 10.1016/j.giant.2025.100352

Bei Wu , Yifan Yan , Yuting Zhu , Changxing Ji , Yangyang Lin , Chao Lang

Natural membrane proteins are molecular machines evolved over billions of years, playing crucial roles in various physiological functions by precisely mediating transmembrane transport processes. Inspired by these marvels, people have developed many artificial transport systems with structures and functions matching those of natural proteins. Compared to proteins in nature, engineered transport systems offer advantage in structural simplicity, stability, and cost-effectiveness. These artificial systems could find applications in areas ranging from medical treatment to new materials, and to biotechnologies. This review begins by examining ionic flow in nature, where the high efficiency and selectivity of protein channels have inspired engineered systems. We then explore different types of artificial transport systems, including artificial channels, transporters, and nanopores, and techniques for characterizing these systems. Applications in therapeutics, biotechnologies, separation, and energy harvesting are discussed. Finally, we offer perspectives and outlook on the further advancement of the artificial ion transport systems.

天然膜蛋白是经过数十亿年进化而来的分子机器，通过精确介导跨膜运输过程，在各种生理功能中发挥着至关重要的作用。受这些奇迹的启发，人们开发了许多人工运输系统，其结构和功能与天然蛋白质相匹配。与自然界的蛋白质相比，工程运输系统在结构简单，稳定性和成本效益方面具有优势。这些人工系统可以在医疗、新材料和生物技术等领域得到应用。本综述从研究自然界中的离子流动开始，其中蛋白质通道的高效率和选择性激发了工程系统。然后，我们探索了不同类型的人工运输系统，包括人工通道、转运体和纳米孔，以及表征这些系统的技术。讨论了在治疗学、生物技术、分离和能量收集方面的应用。最后，对人工离子输运系统的进一步发展进行了展望。

{"title":"Ions in motion: From biological channels to engineered transport systems","authors":"Bei Wu , Yifan Yan , Yuting Zhu , Changxing Ji , Yangyang Lin , Chao Lang","doi":"10.1016/j.giant.2025.100352","DOIUrl":"10.1016/j.giant.2025.100352","url":null,"abstract":"<div><div>Natural membrane proteins are molecular machines evolved over billions of years, playing crucial roles in various physiological functions by precisely mediating transmembrane transport processes. Inspired by these marvels, people have developed many artificial transport systems with structures and functions matching those of natural proteins. Compared to proteins in nature, engineered transport systems offer advantage in structural simplicity, stability, and cost-effectiveness. These artificial systems could find applications in areas ranging from medical treatment to new materials, and to biotechnologies. This review begins by examining ionic flow in nature, where the high efficiency and selectivity of protein channels have inspired engineered systems. We then explore different types of artificial transport systems, including artificial channels, transporters, and nanopores, and techniques for characterizing these systems. Applications in therapeutics, biotechnologies, separation, and energy harvesting are discussed. Finally, we offer perspectives and outlook on the further advancement of the artificial ion transport systems.</div></div>","PeriodicalId":34151,"journal":{"name":"GIANT","volume":"22 ","pages":"Article 100352"},"PeriodicalIF":5.4,"publicationDate":"2025-01-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143100202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

“Clicking” Amphiphilic Block Copolymers onto POSS Core: A General Approach for “Star-like” Polymers with Different Symmetry 将两亲嵌段共聚物 "点击 "到 POSS 核心上：不同对称性 "星状 "聚合物的通用方法

IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2024-11-15 DOI: 10.1016/j.giant.2024.100346

Gang Li, Duohua Jiang, Panpan Ren, Heng Zhao, Kai Zhang, Liping Chang, Zhongguo Liu, Shouzhi Pu

“Star-like” macromolecules have been widely studied because of their unique physical and chemical properties, which play a great role in many important application fields. In this study, a library of star-like amphiphilic block copolymers consisting of a polyhedral oligomeric silsesquioxane (POSS) core and polyethylene glycol-bolck-polystyrene (PEG_m-b-PS_n) diblock copolymer arms with an exact arm number were prepared through a robust copper-catalysed azide-alkyne cycloadditions (CuAAC) and strain-promoted azide-alkyne cycloaddition (SPAAC) click reactions. Moreover, homo- and mikto-arms star polymers with different compositions were obtained by precisely regulating the central symmetry of the POSS core. The target polymers and intermediate products were characterized by nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), Fourier transform infrared (FT-IR) spectroscopy, and matrix-assisted laser desorption ionization time-of-flight (MALDI-ToF) mass spectrometry. This study demonstrates the chemical robustness of the novel POSS-based building block and establishes a general and efficient approach to prepare star-like macromolecules, especially for asymmetric heteroarm star-like macromolecules, which serve as important model compounds in the study of their bulk properties as well as self-assembling behaviors.

"星状 "高分子因其独特的物理和化学性质而被广泛研究，并在许多重要应用领域发挥着重要作用。本研究通过铜催化叠氮-炔环加成（CuAAC）和应变促进叠氮-炔环加成（SPAAC）单击反应，制备了由多面体低聚硅倍半氧烷（POSS）内核和具有精确臂数的聚乙二醇-聚苯乙烯（PEGm-b-PSn）二嵌段共聚物臂组成的星状两亲嵌段共聚物库。此外，通过精确调节 POSS 核心的中心对称性，还获得了不同组成的同臂和米克托臂星型聚合物。通过核磁共振（NMR）、尺寸排阻色谱（SEC）、傅立叶变换红外光谱（FT-IR）和基质辅助激光解吸电离飞行时间质谱（MALDI-ToF）对目标聚合物和中间产物进行了表征。这项研究证明了基于 POSS 的新型构筑模块的化学稳定性，并为制备星状大分子，尤其是不对称杂臂星状大分子提供了一种通用而高效的方法。

{"title":"“Clicking” Amphiphilic Block Copolymers onto POSS Core: A General Approach for “Star-like” Polymers with Different Symmetry","authors":"Gang Li, Duohua Jiang, Panpan Ren, Heng Zhao, Kai Zhang, Liping Chang, Zhongguo Liu, Shouzhi Pu","doi":"10.1016/j.giant.2024.100346","DOIUrl":"10.1016/j.giant.2024.100346","url":null,"abstract":"<div><div>“<em>Star-like</em>” macromolecules have been widely studied because of their unique physical and chemical properties, which play a great role in many important application fields. In this study, a library of star-like amphiphilic block copolymers consisting of a polyhedral oligomeric silsesquioxane (POSS) core and polyethylene glycol-<em>bolck</em>-polystyrene (PEG<em><sub>m</sub></em>-<em>b</em>-PS<em><sub>n</sub></em>) diblock copolymer arms with an exact arm number were prepared through a robust copper-catalysed azide-alkyne cycloadditions (CuAAC) and strain-promoted azide-alkyne cycloaddition (SPAAC) click reactions. Moreover, homo- and mikto-arms star polymers with different compositions were obtained by precisely regulating the central symmetry of the POSS core. The target polymers and intermediate products were characterized by nuclear magnetic resonance (NMR), size exclusion chromatography (SEC), Fourier transform infrared (FT-IR) spectroscopy, and matrix-assisted laser desorption ionization time-of-flight (MALDI-ToF) mass spectrometry. This study demonstrates the chemical robustness of the novel POSS-based building block and establishes a general and efficient approach to prepare star-like macromolecules, especially for asymmetric heteroarm star-like macromolecules, which serve as important model compounds in the study of their bulk properties as well as self-assembling behaviors.</div></div>","PeriodicalId":34151,"journal":{"name":"GIANT","volume":"21 ","pages":"Article 100346"},"PeriodicalIF":5.4,"publicationDate":"2024-11-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699346","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

A dynamic entanglement model for adaptive networks in amorphous polymers with pH-responsive dual-shape memory effect 具有 pH 响应双形记忆效应的无定形聚合物自适应网络的动态纠缠模型

IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2024-11-14 DOI: 10.1016/j.giant.2024.100347

Jiabin Shi , Haibao Lu , Tengfei Zheng , Yong-Qing Fu

The pH-responsive shape memory polymers (pH-SMPs) have recently attracted significant attention due to their unique and spontaneous actuation capabilities. However, there are few constitutive models developed to explore the working principles behind these complex shape memory behaviors. In this study, a dynamic entanglement model was developed for describing the pH-responsive shape memory effect (SME) in SMPs, in which the crosslinking points in polymer networks underwent reversible entanglements and disentanglements. Susceptible-Infected-Susceptible (SIS) model was firstly employed to formulate an entanglement probability function, which was used to identify the working principles for entanglements of polymer networks and shape recovery of the pH-SMPs. An entanglement free-energy function was further formulated to characterize the pH-responsive dual-SMEs based on the Flory-Huggins solution theory. Phase transition theory was then used to characterize glass transition behaviors and recovery strains of the pH-SMPs, by combining Gordon-Taylor and Kohlrausch-Williams-Watts (KWW) equations. Finally, the proposed model was verified using experimental results reported in the literature. This study provides a fundamental approach to explore the working principle and constitutive relationship between reversible entanglement and pH-responsive SME in SMPs.

pH 响应型形状记忆聚合物（pH-SMPs）因其独特的自发致动能力最近引起了广泛关注。然而，目前很少有构成模型可用于探索这些复杂形状记忆行为背后的工作原理。本研究建立了一个动态纠缠模型，用于描述 SMP 中的 pH 响应形状记忆效应（SME），其中聚合物网络中的交联点发生了可逆的纠缠和解除纠缠。首先利用易感-感染-易感（SIS）模型制定了缠结概率函数，并以此确定了聚合物网络缠结和 pH-SMP 形状复原的工作原理。在弗洛里-哈金斯溶液理论的基础上，进一步制定了纠缠自由能函数，以描述 pH 响应双 SME 的特征。然后，结合戈登-泰勒（Gordon-Taylor）方程和 Kohlrausch-Williams-Watts (KWW) 方程，使用相变理论来描述 pH-SMP 的玻璃化转变行为和恢复应变。最后，利用文献报道的实验结果对所提出的模型进行了验证。这项研究为探索 SMP 中可逆缠结和 pH 响应 SME 的工作原理和构成关系提供了一种基本方法。

{"title":"A dynamic entanglement model for adaptive networks in amorphous polymers with pH-responsive dual-shape memory effect","authors":"Jiabin Shi , Haibao Lu , Tengfei Zheng , Yong-Qing Fu","doi":"10.1016/j.giant.2024.100347","DOIUrl":"10.1016/j.giant.2024.100347","url":null,"abstract":"<div><div>The pH-responsive shape memory polymers (pH-SMPs) have recently attracted significant attention due to their unique and spontaneous actuation capabilities. However, there are few constitutive models developed to explore the working principles behind these complex shape memory behaviors. In this study, a dynamic entanglement model was developed for describing the pH-responsive shape memory effect (SME) in SMPs, in which the crosslinking points in polymer networks underwent reversible entanglements and disentanglements. Susceptible-Infected-Susceptible (SIS) model was firstly employed to formulate an entanglement probability function, which was used to identify the working principles for entanglements of polymer networks and shape recovery of the pH-SMPs. An entanglement free-energy function was further formulated to characterize the pH-responsive dual-SMEs based on the Flory-Huggins solution theory. Phase transition theory was then used to characterize glass transition behaviors and recovery strains of the pH-SMPs, by combining Gordon-Taylor and Kohlrausch-Williams-Watts (KWW) equations. Finally, the proposed model was verified using experimental results reported in the literature. This study provides a fundamental approach to explore the working principle and constitutive relationship between reversible entanglement and pH-responsive SME in SMPs.</div></div>","PeriodicalId":34151,"journal":{"name":"GIANT","volume":"21 ","pages":"Article 100347"},"PeriodicalIF":5.4,"publicationDate":"2024-11-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699345","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Limitation and potential of lignin-assisted stabilisation of oriented liquid crystalline cellulosic mesophase 木质素辅助稳定定向液晶纤维素中间体的局限性和潜力

IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2024-11-12 DOI: 10.1016/j.giant.2024.100344

F. Robert Gleuwitz , Gopakumar Sivasankarapillai , Ahmed Bentaleb , Nadine Kohlhuber , Marie-Pierre G. Laborie

This study aimed at progressing in the fundamental understanding of the lignin-assisted microstructural stabilisation observed in solution-processed materials based on the polymer blend of hydroxypropyl cellulose and hardwood organosolv lignin. Mechanical analysis, polarised infrared spectroscopy and wide-angle X-ray scattering of shear cast blend films revealed that the effect of lignin on the flow-oriented cellulosic mesophase is also valid for blends composed of ethyl cellulose as liquid crystalline matrix polymer and lignin derived oligomers from base-catalysed depolymerisation as dispersed “microstructural cementing agent”. The results underline the significant role of the solvent diffusion between the continuous cellulosic and the dispersed lignin phase, which is ascribed to polymer-/oligomer-solvent interactions. An abundance of the solvent within the lignin phase caused the disruption of the microstructural stabilisation effect. The concept of a balanced proton-donor activity was introduced linking the solvent diffusion with the lyotropic liquid crystalline phase formation, the macro- and microstructural blend morphology and aspects regarding the solution processing.

本研究旨在从根本上了解在基于羟丙基纤维素和硬木有机溶胶木质素的聚合物混合物的溶液加工材料中观察到的木质素辅助微结构稳定现象。对剪切浇注共混薄膜进行的机械分析、偏振红外光谱分析和广角 X 射线散射分析表明，木质素对流动性纤维素介相的影响同样适用于由作为液晶基质聚合物的乙基纤维素和作为分散 "微结构粘合剂 "的碱催化解聚产生的木质素低聚物组成的共混物。研究结果强调了溶剂在连续纤维素相和分散木质素相之间扩散的重要作用，这归因于聚合物/低聚物与溶剂之间的相互作用。木质素相中的大量溶剂会破坏微结构稳定效应。我们提出了平衡质子供体活性的概念，将溶剂扩散与各向同性液晶相的形成、宏观和微观混合结构形态以及溶液加工方面联系起来。

{"title":"Limitation and potential of lignin-assisted stabilisation of oriented liquid crystalline cellulosic mesophase","authors":"F. Robert Gleuwitz , Gopakumar Sivasankarapillai , Ahmed Bentaleb , Nadine Kohlhuber , Marie-Pierre G. Laborie","doi":"10.1016/j.giant.2024.100344","DOIUrl":"10.1016/j.giant.2024.100344","url":null,"abstract":"<div><div>This study aimed at progressing in the fundamental understanding of the lignin-assisted microstructural stabilisation observed in solution-processed materials based on the polymer blend of hydroxypropyl cellulose and hardwood organosolv lignin. Mechanical analysis, polarised infrared spectroscopy and wide-angle X-ray scattering of shear cast blend films revealed that the effect of lignin on the flow-oriented cellulosic mesophase is also valid for blends composed of ethyl cellulose as liquid crystalline matrix polymer and lignin derived oligomers from base-catalysed depolymerisation as dispersed “microstructural cementing agent”. The results underline the significant role of the solvent diffusion between the continuous cellulosic and the dispersed lignin phase, which is ascribed to polymer-/oligomer-solvent interactions. An abundance of the solvent within the lignin phase caused the disruption of the microstructural stabilisation effect. The concept of a balanced proton-donor activity was introduced linking the solvent diffusion with the lyotropic liquid crystalline phase formation, the macro- and microstructural blend morphology and aspects regarding the solution processing.</div></div>","PeriodicalId":34151,"journal":{"name":"GIANT","volume":"21 ","pages":"Article 100344"},"PeriodicalIF":5.4,"publicationDate":"2024-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142699344","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Influence of activation/deactivation process on surface-initiated atom transfer radical polymerization: An in silico investigation 活化/失活过程对表面引发的原子转移自由基聚合的影响：一项硅学研究

IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2024-11-06 DOI: 10.1016/j.giant.2024.100345

Zhongyan Zhang , Hui Li , Yuqi Guo , Yao-Hong Xue , Hong Liu

We propose a simulation approach to explore surface-initiated atom transfer radical polymerization (SI-ATRP), in which how the chain growth is affected by activation/deactivation process could be considered explicitly. Our findings indicate that these activation and deactivation mechanisms provide all polymer chains with equal growth opportunities. This process leads to a significant increase of grafting density while concurrently reducing the dispersity of the grafted chains. The ratio of activated and dormant chains is theoretically proved to eventually reach equilibrated within the activation/deactivation process. The shorter lifetime of activation/deactivation cycle leads to an even equal opportunity and a faster “stop-continue” pace for the growth of all chains. Our study is helpful for better understanding the role of activation/deactivation process in SI-ATRP from a microscopic perspective.

我们提出了一种探索表面引发原子转移自由基聚合（SI-ATPR）的模拟方法，其中可以明确考虑激活/失活过程对聚合物链增长的影响。我们的研究结果表明，这些激活和失活机制为所有聚合物链提供了平等的生长机会。这一过程显著增加了接枝密度，同时降低了接枝链的分散性。理论证明，活化链和休眠链的比例最终会在活化/失活过程中达到平衡。较短的激活/失活周期会使所有链的生长机会均等，并加快 "停止-继续 "的速度。我们的研究有助于从微观角度更好地理解活化/去活化过程在 SI-ATRP 中的作用。

引用次数: 0

Homochiral “8″-shaped nanotoroids assembled from polypeptides 由多肽组装而成的同手性 "8″形纳米多面体

IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2024-10-28 DOI: 10.1016/j.giant.2024.100343

Ruiqi Jin, Yue Du, Jiaping Lin, Chunhua Cai

Figure eight-shaped (“8″-shaped) nanotoroids have been observed in DNA and proteins, however, they are rarely reported in synthetic polymer systems. Reported here is the formation of homochiral “8″-shaped nanotoroids from poly(γ-benzyl glutamate) (PBG) homopolymers. The L-type and D-type PBGs, i.e., PBLG and PBDG respectively, form left-handed and right-handed “8″-shaped chiral nanotoroids. The formation of the nanotoroids is achieved in a two-step route. Nanofibers are first self-assembled by the PBG homopolymers, which, with changing solvent nature, break into short nanofibers and twist into “8″-shaped nanotoroids. In such processes, the pendant phenyl groups of PBGs change from an extended to a contract form, which generates the internal stress driving the transition of nanofibers to “8″-shaped nanotoroids. This work not only enriches the topology and preparation method of nanotoroids, but also enhances our ability in controlling polymer nanostructures.

在 DNA 和蛋白质中已经观察到图八形（"8″形）纳米多面体，但在合成聚合物体系中却鲜有报道。本文报告了由聚（γ-苄基谷氨酸）（PBG）均聚物形成的同手性 "8″形纳米陀螺。L 型和 D 型 PBG（即 PBLG 和 PBDG）分别形成左手和右手 "8″形手性纳米多面体。纳米多面体的形成分为两个步骤。首先由 PBG 均聚物自组装成纳米纤维，随着溶剂性质的变化，纳米纤维断裂成短纳米纤维，并扭曲成 "8″形纳米多面体。在这一过程中，PBG 的垂苯基基团从扩展形式变为收缩形式，从而产生内应力，推动纳米纤维向 "8″形纳米多面体转变。这项工作不仅丰富了纳米多面体的拓扑结构和制备方法，而且提高了我们控制聚合物纳米结构的能力。

引用次数: 0

Small dop of comonomer, giant shift of dynamics: α-methyl-regulated viscoelasticity of poly(methacrylamide) hydrogels 少量共聚物掺入，动力学巨变：α-甲基调节聚（甲基丙烯酰胺）水凝胶的粘弹性

IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2024-09-23 DOI: 10.1016/j.giant.2024.100342

Xin Guan , Zhiheng Zhou , Xinzhen Fan , Wenchao Xu , Yijie Jin , Chuanzhuang Zhao

α-Methyl groups play significant roles in the regulation of water molecules within both small molecular systems and bio-macromolecular systems. Systematically studying the influence of α-methyl on the dynamics of water molecules within hydrogel systems is therefore worthwhile. In this study, we prepared a series of hydrogen-bonded (H-bonded) hydrogels with varying densities of α-methyl groups by copolymerizing methacrylamide (MAm) with its α-methyl-absent analogue, acrylamide (Am). Introducing a small amount of Am (≤6 mol%) into the polymer chain resulted in significant shifts in the viscoelasticity of the hydrogels. The hydrogels exhibit a “time-temperature-α-methyl equivalence”, meaning that introduction of α-methyl-absent monomer has effects similar to elevating temperature and prolonging observation time on the dynamic properties. Based on low-field nuclear magnetic resonance spectroscopy and Raman scattering, a “hydrophilic defects-assisted H-bonds dissociation” mechanism is proposed, depicting that the α-methyl-absent monomer can disturb the rearrangement of water molecules surrounding the polymer chain and accelerate chain dissociation. These findings enabled the copolymer hydrogels with functions such as fast self-healing and tunable interface adhesion.

在小分子体系和生物大分子体系中，α-甲基对水分子的调节都起着重要作用。因此，系统研究α-甲基对水凝胶体系中水分子动力学的影响是有价值的。在本研究中，我们通过甲基丙烯酰胺（MAm）与不含α-甲基的类似物丙烯酰胺（Am）共聚，制备了一系列具有不同α-甲基密度的氢键（H-键）水凝胶。在聚合物链中引入少量 Am（≤6 摩尔%）可显著改变水凝胶的粘弹性。水凝胶表现出 "时间-温度-α-甲基等效"，即引入α-甲基缺失单体对动态特性的影响类似于升高温度和延长观察时间。基于低场核磁共振光谱和拉曼散射，提出了 "亲水缺陷辅助 H 键解离 "机理，说明α-甲基缺失单体可干扰聚合物链周围水分子的重排，加速链解离。这些发现使共聚物水凝胶具有快速自愈合和可调界面粘附性等功能。

{"title":"Small dop of comonomer, giant shift of dynamics: α-methyl-regulated viscoelasticity of poly(methacrylamide) hydrogels","authors":"Xin Guan , Zhiheng Zhou , Xinzhen Fan , Wenchao Xu , Yijie Jin , Chuanzhuang Zhao","doi":"10.1016/j.giant.2024.100342","DOIUrl":"10.1016/j.giant.2024.100342","url":null,"abstract":"<div><div><em>α</em>-Methyl groups play significant roles in the regulation of water molecules within both small molecular systems and bio-macromolecular systems. Systematically studying the influence of <em>α</em>-methyl on the dynamics of water molecules within hydrogel systems is therefore worthwhile. In this study, we prepared a series of hydrogen-bonded (H-bonded) hydrogels with varying densities of <em>α</em>-methyl groups by copolymerizing methacrylamide (MAm) with its <em>α</em>-methyl-absent analogue, acrylamide (Am). Introducing a small amount of Am (≤6 mol%) into the polymer chain resulted in significant shifts in the viscoelasticity of the hydrogels. The hydrogels exhibit a “time-temperature-<em>α</em>-methyl equivalence”, meaning that introduction of <em>α</em>-methyl-absent monomer has effects similar to elevating temperature and prolonging observation time on the dynamic properties. Based on low-field nuclear magnetic resonance spectroscopy and Raman scattering, a “hydrophilic defects-assisted H-bonds dissociation” mechanism is proposed, depicting that the <em>α</em>-methyl-absent monomer can disturb the rearrangement of water molecules surrounding the polymer chain and accelerate chain dissociation. These findings enabled the copolymer hydrogels with functions such as fast self-healing and tunable interface adhesion.</div></div>","PeriodicalId":34151,"journal":{"name":"GIANT","volume":"20 ","pages":"Article 100342"},"PeriodicalIF":5.4,"publicationDate":"2024-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142418054","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Binary blends of poly(lactic acid) and poly(methyl methacrylate) for high energy density and charge/discharge efficiency capacitors 用于高能量密度和充放电效率电容器的聚乳酸和聚甲基丙烯酸甲酯二元混合物

IF 5.4 1区化学 Q2 CHEMISTRY, MULTIDISCIPLINARY

GIANT

Pub Date : 2024-09-10 DOI: 10.1016/j.giant.2024.100340

Shuo Zhao , Le Zhou , Junshang Zhang, Yang Shen, Ce-Wen Nan

Polymer dielectrics are widely used in modern power electronics due to their high flexibility and high breakdown strength. However, the limited energy density of current polymer dielectrics limits their wider applications, and there is an urgent need to develop novel polymer dielectric materials. Poly(lactic acid) (PLA) is favored for biological applications due to its biocompatibility and biodegradability. In general, PLA has three optical isomers, namely poly(L-lactide) (PLLA), poly(D-lactide) (PDLA), and poly(DL-lactide) (PDLLA), but the investigation of their dielectric properties remains limited. In this study, a significant increase in energy storage density and charge/discharge efficiency in poly(methyl methacrylate) (PMMA) was achieved by incorporating isomers of PLA into PMMA. Experimental results indicate that the introduction of PLA creates a phase-separated structure within PMMA, and in particular, the introduction of the crystalline region significantly improved the breakdown strength (E_b). Finally, PLLA/PMMA 50/50 and PDLA/PMMA 50/50 exhibit the discharged energy densities of 8.55 J cm⁻³ and 8.18 J cm⁻³, respectively, with charge/discharge efficiencies of 89.6% and 90.9%. This work enables the achievement of all-organic dielectrics with high energy storage density and high efficiency through the construction of phase-separated structures and demonstrates the great potential of biodegradable polymers in electronic devices.

聚合物电介质具有高柔韧性和高击穿强度，因此被广泛应用于现代电力电子设备中。然而，目前聚合物电介质的能量密度有限，限制了其更广泛的应用，因此迫切需要开发新型聚合物电介质材料。聚乳酸（PLA）因其生物相容性和生物可降解性，在生物应用中备受青睐。一般来说，聚乳酸有三种光学异构体，即聚（L-乳酸）（PLLA）、聚（D-乳酸）（PDLA）和聚（DL-乳酸）（PDLLA），但对它们介电性能的研究仍然有限。在本研究中，通过在聚甲基丙烯酸甲酯（PMMA）中加入聚乳酸异构体，实现了聚甲基丙烯酸甲酯（PMMA）储能密度和充放电效率的显著提高。实验结果表明，聚乳酸的引入在 PMMA 中产生了相分离结构，尤其是晶体区的引入显著提高了击穿强度（Eb）。最后，PLLA/PMMA 50/50 和 PDLA/PMMA 50/50 的放电能量密度分别为 8.55 J cm-3 和 8.18 J cm-3，充放电效率分别为 89.6% 和 90.9%。这项工作通过构建相分离结构实现了高储能密度和高效率的全有机电介质，展示了生物可降解聚合物在电子器件中的巨大潜力。

{"title":"Binary blends of poly(lactic acid) and poly(methyl methacrylate) for high energy density and charge/discharge efficiency capacitors","authors":"Shuo Zhao , Le Zhou , Junshang Zhang, Yang Shen, Ce-Wen Nan","doi":"10.1016/j.giant.2024.100340","DOIUrl":"10.1016/j.giant.2024.100340","url":null,"abstract":"<div><p>Polymer dielectrics are widely used in modern power electronics due to their high flexibility and high breakdown strength. However, the limited energy density of current polymer dielectrics limits their wider applications, and there is an urgent need to develop novel polymer dielectric materials. Poly(lactic acid) (PLA) is favored for biological applications due to its biocompatibility and biodegradability. In general, PLA has three optical isomers, namely poly(L-lactide) (PLLA), poly(D-lactide) (PDLA), and poly(DL-lactide) (PDLLA), but the investigation of their dielectric properties remains limited. In this study, a significant increase in energy storage density and charge/discharge efficiency in poly(methyl methacrylate) (PMMA) was achieved by incorporating isomers of PLA into PMMA. Experimental results indicate that the introduction of PLA creates a phase-separated structure within PMMA, and in particular, the introduction of the crystalline region significantly improved the breakdown strength (<em>E</em><sub>b</sub>). Finally, PLLA/PMMA 50/50 and PDLA/PMMA 50/50 exhibit the discharged energy densities of 8.55 J cm<sup>−3</sup> and 8.18 J cm<sup>−3</sup>, respectively, with charge/discharge efficiencies of 89.6% and 90.9%. This work enables the achievement of all-organic dielectrics with high energy storage density and high efficiency through the construction of phase-separated structures and demonstrates the great potential of biodegradable polymers in electronic devices.</p></div>","PeriodicalId":34151,"journal":{"name":"GIANT","volume":"20 ","pages":"Article 100340"},"PeriodicalIF":5.4,"publicationDate":"2024-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.sciencedirect.com/science/article/pii/S2666542524001048/pdfft?md5=5fdaadba5fe8c446d394f5b0099d8249&pid=1-s2.0-S2666542524001048-main.pdf","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142270615","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

GIANT最新文献