CHEMISTRY-A EUROPEAN JOURNAL
·
2018
·Vol. 25
·期 6
·1535-1542
·
IF 5.16
Hairan Zhang,Qiuyue Zhang,Ling Zhang,Tingting Pei,Erni Li,Huiting Wang,Qian Zhang,Lixin Xia
Graphical Making the switch : A thermally responsive poly( N -isopropylacrylamide)-modified graphene oxide (PNIPAm-GO) nanocomposite was synthesized by using a covalent “grafting-from” strategy. It was further applied as an intelligent PNIPAm-GO/GC electrode to display switchable electrocatalysis toward 1,4-dihydro-β-nicotinamide adenine dinucleotide and dopamine (see scheme). Poly( N -isopropylacrylamide)-modified graphene oxide (PNIPAm-GO), which is a type of thermally responsive GO, was designed and synthesized through a covalent “grafting-from” strategy. The as-prepared modified nanosheets integrated the individual advantages of two components, such as the thermal sensitivity of the PNIPAm terminal as well as the conductivity and the open 2D structure of the GO substrate. PNIPAm-GO was able to perform the reversible regulation of hydrophilicity/hydrophobicity in aqueous solution upon variations in the temperature. Such a unique property might also lead to the utilization of PNIPAm-GO as an intelligent electrode material to achieve a switchable electrochemical response toward a [Fe(CN) 6 ] 3−/4− probe. The PNIPAm-GO modified glassy carbon electrode (PNIPAm-GO/GC electrode) was able to exhibit better electrochemical performance in an ON/OFF switching effect than the PNIPAm-modified glassy carbon electrode (PNIPAm/GC electrode) without GO owing to the intrinsic properties and large surface area of the introduced GO. Moreover, it was found that the PNIPAm-GO/GC electrode also displayed excellent thermally responsive electrocatalysis toward the detection of 1,4-dihydro-β-nicotinamide adenine dinucleotide (NADH) and dopamine (DA), which resulted in two different catalytic statuses on the same electrode. This kind of switchable catalytic performance of the PNIPAm-GO/GC electrode might greatly enhance the flexibility of its application, and thus it is expected to have wide potential for applications in the fields of biosensors and biocatalysis.
研究领域:
材料科学
·
生物传感
·
电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2019
·Vol. 11
·期 2
·253
·
IF 3.164
Zheng Cao,Yuyuan Chen,Dan Li,Junfeng Cheng,Chunlin Liu
A SiO2microsphere imprinted by phosphate ions was prepared with the use of phosphate ion as the template molecule and tetraethoxysilane as the precursor. Thereafter, the imprinted SiO2microspheres were modified with 3-(trimethoxysilyl)propyl methacrylate (TMSPMA@SiO2), followed by introducing the double bond. In the presence of TMSPMA@SiO2, usingN-isopropylacrylamide as monomer, and potassium persulfate as initiator, polymer/inorganic hybrid particles (PNIPAM/SiO2) were prepared. Fourier transform infrared spectroscopy, thermogravimetric analysis, nitrogen adsorption-desorption test, and transmission electron microscope were employed for the characterization of molecular imprinted SiO2microspheres and PNIPAM/SiO2hybrid particles. The effects of phosphate concentration, pH value, and adsorption temperature on the phosphate binding properties of PNIPAM/SiO2hybrid particles were studied by UV-vis spectrophotometer. The experimental results shed light on the fact that the PNIPAM structure is beneficial for the improvement of the adsorption ability of phosphate-imprinted SiO2microspheres. With the increase in the initial phosphate concentration, the adsorption capacity of hybrid particles to phosphate ions increased to 274 mg/g at pH = 7 and 15 °C. The acid condition and the temperature below the low critical solution temperature (LCST) of PNIPAM are favorable to the adsorption of phosphate ions by PNIPAM/SiO2hybrid particles, and the maximum adsorption capacity can reach 287 mg/g (at pH = 5 and 15 °C). The phosphate imprinted polymer/inorganic hybrid material is expected to be put to use in the fields of phosphate ions adsorption, separation, and recovery.Keywords:N-isopropylacrylamide;molecular imprinting;polymer/inorganic;phosphate;binding
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2016
·
IF 4.219
Jinguang Wei,Yufei Chen,Hongzhi Liu,Chungui Du,Huilong Yu,Zhongxi Zhou
In this study, TEMPO-oxidized bamboo cellulose nanofibers (TO-CNF) with anionic carboxylate groups on the surfaces were in-situ incorporated into poly( N -isopropylacrylamide) (PNIPAm) matrix to improve its thermo-responsive and mechanical properties during the polymerization. The microstructure, swelling behaviors, and compressive strength of resultant PNIPAm composite hydrogels with varying contents of TO-CNFs (0–10 wt%) were then examined, respectively. Modified hydrogels exhibited the similar light transparency to pure PNIPAm one due to the formation of semi-IPN structure between PNIPAm and TO-CNF. FT-IR spectra demonstrated that the presence of TO-CNF did not alter the position of characteristic peaks associated with PNIPAm. SEM observation suggested that the pore size of PNIPAm hydrogels was markedly increased after the incorporation of TO-CNF. Also, the composite hydrogels showed superior swelling behavior and much improved compression properties with respect to pure PNIPAm one. Thus, TO-CNF appeared to be a “green” nanofiller that can simultaneously improve swelling and mechanical properties of PNIPAm hydrogel.
研究领域:
材料科学
·
生物材料
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2022
·
IF 10.723
Yang Liu,Qunfeng Chen,Gengmei Liu,Tao Tao,Haodong Sun,Zhenhui Lin,Lihui Chen,Qingxian Miao,Jianguo Li
Dynamic transparent-opaque transition behavior endows the stimuli-chromic materials with the solar modulation capability. However, these materials commonly involve the high manufacturing cost and complexity, the additional consumption of electric energy for solar modulation, or the weak effectiveness of light management. Herein, we develop a low-cost yet broadband light management sodium carboxymethyl cellulose-caging-poly(N-isopropylacrylamide) thermochromic composite (i.e., CMC/PNIPAM), where the nanoscale-skeleton CMC molecules well cage the PNIPAM molecules, which enables the homogeneous dispersion and sufficient distribution of the PNIPAM nanogels in the system. The CMC/PNIPAM features the excellent solar-modulation capability (including optical transmittance modulation of 68.17% and infrared transmittance modulation of 48.50%) and a low phase temperature of 30 °C, as well as the long-term stability of dynamic transparent-opaque transition. Such merits of the broadband light management, low cost, simply fabrication as well as scaling up, make the CMC/PNIPAM function as a promising candidate for the energy-saving buildings and construction.
研究领域:
材料科学
·
能源工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LANGMUIR
·
2023
·
IF 3.9
Manting Wang,Rongrong Fan,Qingjian Yu,Jie-Xin Wang,Yuan Le,Jian-Feng Chen
Controlled pesticide delivery systems offer many distinctive advantages over conventional pesticide formulations. In this work, degradable poly(N-isopropylacrylamide) (PNIPAM)–tannic acid (TA) microgels and multifunctional PDA@PNIPAM-TA nanocomposites were prepared in a high-gravity rotating packed bed reactor (RPB) for smart pesticide delivery and release. The as-prepared microgels and nanocomposites showed reversible temperature-dependent swelling/deswelling behavior and irreversible pH-induced degradation. A dynamic contact angle test suggested that the introduction of TA and PDA into the PNIPAM matrix could enhance foliar adhesion and deposition efficiency. The nanocomposites were further used for the encapsulation and delivery of imidacloprid (IMI) to protect it from rapid photolysis and improve its pest-control efficiency. Their thermoresponsive behavior as well as pesticide loading capacity could be tuned by tailoring the PNIPAM-TA shell thickness, which could be varied by the NIPAM amount. The release rate of IMI from the core/shell nanocomposites was positively correlated with environmental temperature and near-infrared (NIR) light, which was adaptive to the positive temperature-dependent toxicity correlation of IMI and the increasing trend of pests under high temperature. The cumulative release of IMI was 23.5% at 25 °C, while it was 81.2% at 40 °C after 24 h of incubation, and the release rate was greatly enhanced under NIR irradiation. The results indicated that the facile control of pesticide release could be realized by regulating environmental conditions. This work also provides an idea for using high-gravity technology to conveniently construct a smart, effective, and environmentally friendly pesticide delivery system for sustainable crop protection.
研究领域:
材料科学
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化学工程
·
农业科学
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纳米技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Applied Polymer Materials
·
2020
·
IF 0
Dong Wang,Yuzheng Xia,Dong Zhang,Xiaomeng Sun,Xiaonong Chen,Susan Oliver,Shuxian Shi,Lei Lei
Most injectable hydrogels are prone to irreversible deformation or damage under sustained shear forces and exhibit low mechanical properties, which limit their practical applications in biological engineering. In this work, the first hydrogen-bonding reinforced injectable thermoresponsive hydrogel system has been fabricated through an in situ hydrazide–aldehyde cross-linking reaction between hydrazide-functionalized poly(N-isopropylacrylamide) (PNIPAM) and dialdehyde dextrin. The mechanical strength and stability of the hydrogel were reinforced by the introduction of intermolecular hydrogen-bonding from poly(N-acryloyl glycinamide) (PNAGA), which possesses great biocompatibility and similarity to PNIPAM. The internal morphology, dynamic moduli, de-cross-linking properties, and temperature responsiveness of the hydrogels were systematically investigated. Upon hydrogen-bonding reinforcement, the hydrogel elasticity, reflected by the maximum storage modulus, dramatically increased from 90.2 to 517.0 kPa, which is about a 570% increase compared with unreinforced hydrogels. In addition, the mechanical properties of the hydrogel were reinforced as the de-cross-linking could be inhibited by PNAGA-based hydrogen-bonding. The temperature release behavior of the hydrogel was assessed with a model drug (propranolol hydrochloride, PHCl) and could be precisely controlled by adjusting the environmental temperature between 25 and 37 °C. Therefore, PNAGA reinforced thermoresponsive hydrogels are promising functional biological materials for use in tissue-repair engineering and controlled-release drug delivery.
研究领域:
生物材料
·
组织工程
·
药物递送系统
✓ 已验证
DOI
BIOMACROMOLECULES
·
2024
·
IF 5.5
Yang Yang,Xuanhe You,Tao Deng,Mingyang Li,Yuan Liu,Mingjie Xu,Yong Nie,Shi-Mei Xu,Bin Shen
Hydrogels are considered as a potential cartilage replacement material based on their structure being similar to natural cartilage, which are of great significance in repairing cartilage defects. However, it is difficult for the existing hydrogels to combine the high load bearing and low friction properties (37 °C) of cartilage through sample methods. Herein, we report a facile and new fabrication strategy to construct the PNIPAm/EYL hydrogel by using the macrophase separation of supersaturated N-isopropylacrylamide (NIPAm) monomer solution to promote the formation of liposomes from egg yolk lecithin (EYL) and asymmetric template method. The PNIPAm/EYL hydrogels possess a relatively high compressive strength (more than 12 MPa), fracture energy (9820 J/m2), good fatigue resistance, lubricating properties, and excellent biocompatibility. Compared with the PNIPAm hydrogel, the friction coefficient (COF 0.046) of PNIPAm/EYL hydrogel is reduced by 50%. More importantly, the COF (0.056) of PNIPAm/EYL hydrogel above lower critical solution temperature (LCST) does not increase significantly, exhibiting heat-tolerant lubricity. The finite element analysis further proves that PNIPAm/EYL hydrogel can effectively disperse the applied stress and dissipate energy under load conditions. This work not only provides new insights for the design of high-strength lubricating hydrogels but also lays a foundation for the treatment of cartilage injury as a substitute material.
研究领域:
生物材料学
·
组织工程学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
ACS Omega
·
2020
·
IF 2.87
Jingwei Liu,Xuhao Fan,Yufeng Tao,Chunsan Deng,Kewang Yu,Wenguang Zhang,Leimin Deng,Wei Xiong
The widespread use of stimuli-responsive hydrogels is closely related to their synthesis efficiency. However, the widely used thermal-responsive poly(N-isopropylacrylamide) (PNIPAM) hydrogels usually require a time-consuming synthesis process to produce (more than 12 h) and exhibit a relatively slow response speed in the field of cryo-polymerization. In this study, a sequence of thawing polymerization after freezing polymerization by a two-step method of free radical polymerization for the efficient synthesis of PNIPAM hydrogels (merely 2 h) with an excellent comprehensive performance is demonstrated. Results show that the overall performance of the as-synthesized PNIPAM hydrogels is at the top level among reported works despite the significantly reduced preparation time. Moreover, after incorporating multi-walled carbon nanotubes (MWNTs), the PNIPAM hydrogels exhibit a rapid near-infrared (NIR) light-response and programmable shape-morphing capability. It is believed that such a viable and time-saving synthetic method for producing PNIPAM hydrogels of high performance will lay a solid foundation for drug delivery and smart actuators.
研究领域:
材料科学
·
生物医学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
LANGMUIR
·
2017
·
IF 3.833
Rui Chen,Ning Ren,Xin Jin,Xinyuan Zhu
Poly(N-isopropylacrylamide) (PNIPAM)-based ionic microgels with different diameters were first prepared and then used as particulate stabilizer or seed in dispersion polymerization of styrene. The role of PNIPAM-based ionic microgels could be transformed from particulate stabilizer to seed by controlling the water content in methanol–water mixture. Generally, PNIPAM-based ionic microgels served as particulate stabilizer in methanol in the absence of water, leading to the formation of spherical polystyrene nanoparticles. However, they turned into seeds when water was added into the methanol solution, with the formation of octopus-like nanoparticles. Further study demonstrated that the mechanism for this role transition was related to the special thermosensitivity of PNIPAM microgels in methanol–water mixture. They lost their thermosensitivity in pure methanol solution but restored their thermosensitivity when increasing the water content in methanol–water mixture.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Huijing Li,Yun Liang,Guorong Gao,Shuxin Wei,Yukun Jian,Xiaoxia Le,Wei Lu,Qingquan Liu,Jiawei Zhang,Tao Chen
Living creatures have the nature of actuating and sensing under external stimuli to better adapt to the environment. For instance, the combination of muscles actuation and skin sensing ensures our intelligent interaction with external environments. In terms of the soft robot, implanting sensation and actuation in one system can assist us to control it better and more efficiently. However, in the development of biomimetic materials, the simultaneous realization of actuating and sensing performance in bionic soft robots is still a great challenge. Here, we propose a novel asymmetric bilayer CNTs-elastomer/PNIPAm hydrogel composite with integrated actuating and sensing performances. Due to the excellent photothermal effect of CNTs and thermo-responsiveness of PNIPAm, under the NIR irradiation, the PNIPAm hydrogel layer would shrink and the bilayer composite would thus perform a bending deformation. At the same time, based on a piezoresistive sensing mechanism of the CNTs-elastomer, the actuating procedure can be recorded. This work may open up a new insight in the designing and fabricating intelligent biomimetic hydrogel soft robots with integrated self-sensing capacity.
研究领域:
材料科学
·
仿生学
·
软体机器人
✓ 已验证
DOI
高影响因子
Advanced Science
·
2025
·
IF 14.1
Shuo Yang,Sizhe Tang,Yufeng Cai,Zhiming Ye,Xiangbin Zou,Xueyu Yuan,Yujie Song,Bing Li,Dongyan Tang,Ming Liu
Passive thermal-regulation strategies have become increasingly important due to the strain alleviated on power grids for temperature management. Designing a system capable of automatically switching between cooling and heating modes in response to changing ambient conditions presents several specific challenges that engineers and researchers are actively addressing. In this research, a CaCl 2 incorporated PNIPAM coated fluorinated poly(aryl ether) (FPAE) porous film with tunable reflectance is developed. The aim is to mitigate the reliance on active cooling systems, which consume significant amounts of energy. The moisture-temperature dual sensitive film exhibits a tunable reflectance range between 91.1% and 39.1% via phase change of the PNIPAM layer. Coupled with an infrared emissivity of 96.0%, a daytime cooling of 10 °C compared to the control experiment is achieved. Coating the film with a photothermal layer results in an adaptive Janus film that is capable of autonomous switching between heating and cooling, and demonstrates a heating of 22.5 °C in a cold environment. The facile preparation method, excellent cyclic stability, mechanical properties, and UL-94 V-0 rating enable promising applications of the smart film under diverse living environments.
研究领域:
材料科学
·
环境科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry B
·
2017
·Vol. 5
·期 39
·7974-7984
·
IF 4.543
Yuzheng Wu,Haifeng Li,Zhouquan Rao,Huaqiang Li,Yan Wu,Jianhao Zhao,Jianhua Rong
The controlled protein adsorption and delivery of thermosensitive poly(N-isopropylacrylamide) (PNIPAM) nanogels were investigated under different temperatures, pH values and ionic strengths by using bovine serum albumin (BSA) as a model protein. The BSA adsorption in deionized water was due to one or several of four contributions, i.e. the electrostatic attraction between BSA and nanogels, the seizing action of nanogels to BSA, the hydrophobic interaction between BSA and nanogels, and the physical diffusion of BSA, depending on the temperature and pH value. At 37 °C and pH 4.0, the largest BSA adsorption of 23.5 μg mg−1 was achieved by the above four contributions following electrostatic attraction (48%) > seizing action (21%) > hydrophobic interaction (16%) > physical diffusion (15%). The BSA adsorption in different sodium chloride solutions exhibited a maximum of 17.2 μg mg−1 at 0.03 M, which was influenced by the charge shielding of Na+ ions, salting out of BSA and nanogel aggregation. Most adsorbed BSA molecules were distributed on the nanogel surface except a few standing in the nanogel interior. The adsorbed BSA could be controllably delivered by tailoring the temperature and pH value, and with the aid of sodium dodecyl sulfate. The conformation of BSA adsorbed in hydrochloric acid solution (pH 4.0) significantly changed due to the acid environment and the electrostatic attraction between BSA and nanogels, but it could be completely recovered when BSA was delivered in deionized water or physiological saline. This work is instructive to design the controllable adsorption and delivery of proteins by using PNIPAM-based hydrogels as carriers.
研究领域:
生物材料学
·
药物递送系统
·
生物化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）