BIOMACROMOLECULES
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2018
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IF 5.738
Chao Xing,Zhekun Shi,Jiliang Tian,Jing Sun,Zhibo Li
Stimuli-responsive polymers have received increasing interest for a variety of applications. Here, we report a series of unique charge-determined thermoresponsive polypeptoids synthesized by a combination of ring-opening polymerization and click chemistry. The LCST-type and UCST-type behavior is mainly dominated by the charge state on the side chain. Further, the phase transition temperature highly depends on the degree of polymerization, the side-chain architecture, the pH value, and so on. The obtained polypeptoid solutions exhibit good stability against temperature and salt concentration. To our knowledge, this report presents the first charge-determined LCST/UCST-type polymer from identical homopolymer backbone that displays a wide range of tunable cloudy points in aqueous media. We propose the hydrogen-bonding interaction plays a critical part on the solution behavior. These features make polypeptoids ideal candidates for highly designable stimuli-responsive polymeric materials.
研究领域:
高分子化学
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材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ADVANCED FUNCTIONAL MATERIALS
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2024
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IF 18.5
Jiaqing He,Qiang Zhou,Zhiqing Ge,Shunfeng Jiang,Jiahe Li,Wei Feng,Haiyang Yang
Temperature-responsive hydrogels including lower critical solution temperature (LCST)- and upper critical solution temperature (UCST)-type hydrogels are attractive in various fields. However, the swift switch between LCST and UCST stimuli-responsive behaviors remains intriguing and challenging. Here is reported a kind of hydrogel with pH-gated LCST and UCST response behaviors. This is achieved using the hydrogen bonding between carboxylic acid groups of poly(acrylic acid- co -acrylamide) and hydroxyl groups of hydroxypropyl cellulose (HPC). The poly(acrylic acid- co -acrylamide)-HPC (PACA-HPC) hydrogels exhibit pH-gated reversible LCST-UCST phase transition behavior. When the transparent PACA-HPC hydrogel is placed in an acid bath, the COO − groups get protonated, rapidly forming hydrogen bonds with HPC to render a light-scattering state making the hydrogel opaque. Furthermore, the opaque hydrogel exhibits UCST phase transition behavior at 20–45 °C. When the opaque PCAC-HPC hydrogel is placed in an alkaline environment, hydrogen-bonded complexes gradually dissociate as the COOH groups are deprotonated to form a homogeneous transparent state. The transparent hydrogel exhibits LCST phase transition behavior at 20–45° C. Therefore, is shown the hydrogen bonding strategy to fabricate hydrogels with tunable LCST and UCST responses. With this pH-gated hydrogel with switchable LCST/UCST responsive behaviors, are demonstrated its applications in smart windows and information encryption.
研究领域:
材料科学
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化学工程
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生物医学工程
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2023
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IF 6
Xinyu Ma,Pan Du,Ben Niu,Jiaxuan Zhang,Huaisong Yong,Xianru He
Though the mechanism of temperature-induced lower critical solution temperature (LCST) in water is clear for the classic homopolymer poly( N -isopropylacrylamide) (PNIPAM), the LCST of other homopolymer or copolymer remains to be understood. In this work, a novel random copolymer poly(2-hydroxyethyl- co -methyl acrylate) (P(HEA- co -MA)) was prepared. The LCST of the copolymer P(HEA- co -MA) can vary from 11 °C to 65 °C by adjusting flexibly the ratio of the two monomers, showing a broad tunable range. The experimental results showed that the balance of hydrogen bond bridge formed by P(HEA- co -MA) in water and the hydrophobic interaction between polymers can cause the LCST transition of P(HEA- co -MA). An interesting observation is that the sharp phase transition (cosolvency) of P(HEA- co -MA) exists when a rather small amount of alcohol or water is added in polymer solutions at constant temperatures. Moreover, it was found that the increase of LCST is correlated with the increase of alcohol concentration in the water-rich regime, but the decrease of upper critical solution temperature (UCST) is related to the increase of water concentration in the alcohol-rich regime. This work shed light on the understanding of cosolvency by studying the solution behavior of copolymer P(HEA- co -MA) in mixed solvents, which can be of interest for the design of stimuli-responsive polymer materials by variation in solvent composition.
研究领域:
高分子化学
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材料科学
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
CHINESE JOURNAL OF POLYMER SCIENCE
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2023
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IF 4.3
Zou Zhi,Xu Xiang,Zhao Hai-Tao,Cheng Jian-Nan,He Wei-Wei,Zhang Li-Fen,Cheng Zhen-Ping
Temperature-responsive polymers have garnered significant attention due to their ability to respond to external stimuli. In this work, dual temperature-responsive block copolymers are synthesized via reversible addition-fragmentation chain transfer polymerization (RAFT) polymerization utilizing zwitterionic monomer methacryloyl ethyl sulfobetaine (SBMA) and N -isopropyl acrylamide (NIPAAm) as monomers. The thermal responsive behaviors can be easily modulated by incorporating additional hydrophobic monomer benzyl acrylate (BN) or hydrophilic monomer acrylic acid (AA), adjusting concentration or pH, or varying the degree of polymerization of the block chain segments. The cloud points of the copolymers are determined by UV-Vis spectrophotometry, and these copolymers exhibit both controlled upper and lower critical solubility temperatures (LCST and UCST) in aqueous solution. This study analyzes and summarizes the influencing factors of dual temperature responsive block copolymers by exploring the effects of various conditions on the phase transition temperature of temperature-sensitive polymers to explore the relationship between their properties and environment and structure to make them more selective in terms of temperature application range and regulation laws. It is very interesting that the introduction of poly-acrylic acid (PAA) segments in the middle of di-block copolymer PSBMA 55 - b -PNIPAAm 80 to form PSBMA 55 - b -PAA x - b -PNIPAAm 80 results in a reversal of temperature-responsive behaviors from ‘U’ (LCST < UCST) to ‘n’ (LCST > UCST) type, while the copolymer PSBMA 55 - b -P(NIPAAm 80 - co -AA x ) not. This work provides a clue for tuning the phase transition behavior of polymers for manufacture of extreme smart materials.
研究领域:
材料科学
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高分子化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF MOLECULAR LIQUIDS
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2023
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IF 6
Zihao Dong,Yajuan Qu,Yuyang Jiao,Ke Xue,Wenguang Zhu,Hai Liu,Jianguang Qi,Yinglong Wang
A series of poly(1-vinyl-3-methylimidazole dimethyl phosphate- co -N-isopropylacrylamide) oligomers was synthesized by reversible addition-fragmentation chain transfer polymerization. The co-oligomers exhibited a pH-tunable lower critical solution temperature (LCST) phase transition in aqueous solutions. By changing the pH of the aqueous solution (HCI), the hydrogen bonding between the internal molecules of the co-oligomers and water molecules was weakened, which effectively reduced the cloud-point temperature. Poly(1-vinyl-3-methylimidazole dimethyl phosphate- co - N -isopropylacrylamide) oligomers exhibit an upper critical solution temperature (UCST) type of phase transition in an ester solution, which is associated with the formation and breaking of hydrogen bonds within the co-oligomers molecules. FT-IR analysis revealed the effect of temperature on hydrogen bonding between the functional groups. Energy decomposition, Electrostatic Potential (ESP), Atoms-in-Molecules (AIM), and Interaction region indicator (IRI) analyses demonstrated the presence of hydrogen bond donors N–H and imidazole ring C–H, and hydrogen bond acceptors C = O and P = O in the co-oligomers. The sites of hydrogen bonding between the co-oligomers and the solvent molecules as well as intermolecular forces were found to be the main factors contributing to the LCST/UCST-type phase transition.
研究领域:
高分子化学
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物理化学
✓ 已验证
DOI
高影响因子
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