SENSORS AND ACTUATORS B-CHEMICAL
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2016
·
IF 4.758
Degang Jiang,Huihui Zhu,Wenrong Yang,Liang Cui,Jingquan Liu
Thermo-responsive graphene-polymer films have been obtained by the modification of large CVD graphene films with pyrene-terminated poly( N -isopropylacrylamide) (PNIPAAm) via non-covalent π-π stacking interactions. Pyrene-terminated PNIPAAm was prepared by reversible addition fragmentation chain transfer (RAFT) polymerization using a pyrene-functionalized RAFT agent . Since PNIPAAm possesses a lower critical solution temperature (LCST) of 32 °C, the as-prepared graphene-PNIPAAm films could be reversibly deformed as a result of the morphology response of PNIPAAm to the environmental temperature variation. In addition, the thermo-triggered deformation of the graphene-PNIPAAm films was observed to be reversible and controllable by manipulation of the environmental temperature. Atomic force microscopy (AFM) and high-resolution SEM analysis evidenced the successful attachment of the PNIPAAm on the graphene surface. The thickness of the polymer was revealed by high-resolution scanning electron microscopy (SEM). The successful stepwise fabrication of the CVD graphene-polymer composite films was also characterized using Raman spectroscopy and X-ray photoelectron spectroscopy (XPS). These thermo-responsive composite films would be highly desirable for a wide range of applications, such as thermo-responsive actuators, a thermo-responsive intelligent switch was fabricated using these thermo-responsive graphene composite films.
研究领域:
材料科学
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高分子化学
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
ACS Applied Materials & Interfaces
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2011
·
IF 2.925
Lei Wang,Ke Zeng,Sixun Zheng
Hepta(3,3,3-trifluoropropyl) polyhedral oligomeric silsesquioxane (POSS)-capped poly(N-isopropylacrylamide) (PNIPAAm) telechelics with variable lengths of PNIPAAm midblocks were synthesized by the combination of reversible addition−fragmentation chain transfer polymerization (RAFT) and the copper-catalyzed Huisgen 1,3-cycloaddition (i.e., click chemistry). The POSS-capped trithiocarbonate was synthesized and used as the chain transfer agent for the RAFT polymerization of N-isopropylacrylamide. The organic−inorganic amphiphilic telechelics were characterized by means of nuclear magnetic resonance spectroscopy (NMR) and gel permeation chromatography (GPC). Atomic force microscopy (AFM) shows that all the POSS-capped PNIPAAm telechelics exhibited microphase-separated morphologies, in which the POSS terminal groups were self-assembled into the microdomains and dispersed into the continuous PNIPAAm matrices. The POSS nanodomains could behave as the physical cross-linking sites and as a result the physical hydrogels were formed while these POSS-capped PNIPAAm telechelics were subjected to the solubility tests with water. These physical hydrogels possessed well-defined volume phase transition phenomena and displayed rapid reswelling and deswelling thermoresponsive behavior compared to control PNIPAAm hydrogel.
研究领域:
材料科学
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高分子化学
✓ 已验证
DOI
PubMed
高影响因子
LANGMUIR
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2010
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IF 3.898
Jinqiang Jiang,Qiaozhen Shu,Xin Chen,Yiqun Yang,Chenglin Yi,Xiaoqing Song,Xiaoya Liu,Mingqing Chen
A novel photosensitive C-PNIPAAm comprising hydrophilic PNIPAAm conjugated with a relatively short but very hydrophobic coumarin part was designed and prepared using a coumarin-containing disulfide derivative (C-S-S-C) as transfer agent in the presence of Bu3P and water. It was found that C-PNIPAAm can form polymer micelles in aqueous solution. And the micellar morphology in aqueous solution can be photoswitched into hollow spheres according to the photodimerization of coumarin end groups upon 365 nm irradiation and reform the micellar morphology after the subsequent photoscission of dimers upon 254 nm. This instant morphology changing phenomenon was successfully monitored by dynamic light scattering (DLS) and transmission electron microscopy (TEM) measurements. TEM observations showed the small spherical shape of micelles with diameter at 30−50 nm before photo-cross-linking, the big vesicles with diameter at 200−350 nm after photo-cross-linking, and the small micelles with diameter at 30−50 nm after the subsequent photo-de-cross-linking in the first irradiation cycle. The reason for this significant morphology switching can be attributed to the reversible photoinduced amphiphilic structure transformation between the telechelic “hydrophobic end−hydrophilic chain” structure and the ABA type of “hydrophilic chain−hydrophobic center−hydrophilic chain” one upon alternating irradiation.
研究领域:
高分子化学
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材料科学
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纳米技术
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
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2013
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IF 2.112
Xiumei Tai,Jing hong Ma,Zhiping Du,Wanxu Wang
The temperature sensitive SiO 2 /PNIPAAm composite microspheres were designed and successfully synthesized. The influences of monomer concentration, reaction time, reaction temperature and initiator amount on water contact angel of the prepared microspheres were investigated. The structure, morphology, and surface composition were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Transmission Electron Microscopy (TEM), X-ray Photoelectron Spectroscopy (XPS). The temperature sensitive properties in aqueous solution were studied by water contact angle measurement instrument and dynamic light scatter (DLS). The results show that the low critical solution temperature (LCST) of SiO 2 /PNIPAAm composites is around 304 K and the particle is monodisperse microsphere .
研究领域:
高分子材料学
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纳米医学
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药物递送系统
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生物材料
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温敏材料
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胶体与界面化学
✓ 已验证
DOI
高影响因子
POWDER TECHNOLOGY
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2012
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IF 2.08
Xiumei Tai,Jing hong Ma,Zhiping Du,Wanxu Wang,Jianghong Wu
The thermal responsive SiO 2 -PNIPAAm composites were designed and successfully synthesized. The structure, morphology, surface composition and temperature sensitive property in aqueous solution were investigated by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), contact angle measurement instrument and dynamic light scatter (DLS). FTIR measurement and N1s and C1s core-level spectrum of XPS illustrate that PNIPAAm is grafted availably. TEM analysis revealed the difference between bare SiO 2 and PNIPAAm-functionalized SiO 2 . The measurements of water contact angle and DLS show that the hydration transition temperature of the thermal responsive SiO 2 -PNIPAAm composites is 304 K. The different grafted PNIPAM content has the obvious effect on the water contact angle measure and DLS for SiO 2.
研究领域:
材料科学
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高分子化学
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纳米技术
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生物医学工程
✓ 已验证
DOI
高影响因子
COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2020
·
IF 3.99
Dongdong Zhang,Xuetao Tian,Huanhuan Li,Yiping Zhao,Li Chen
A novel PNIPAAm-CD hydrogel with good adsorption property and stable fluorescence detection for Fe 3+ was prepared by copolymerizing PCDs with NIPAAm monomers. As a fluorescence probe, carbon quantum dots (CDs) were modified by glycidyl methacrylate (GMA) to obtain PCDs, which had double bond and could react with N-isopropyl acrylamide to form hydrogel. The functionalization of the amine groups on the surface of the PCDs enables PNIPAAm-CD hydrogel also exhibits photoluminescence behavior. In addition, the PNIPAAm-CD hydrogels stably shows higher adsorption performance for Fe 3+ than the pure PNIPAAm hydrogel. The honeycomb PNIPAAm-CD hydrogel had a good quenching response to metallic iron ions, and the detection limit was as low as 0.27 μM in the range of 1μM～1mM. The results of adsorption isotherms and adsorption kinetics showed that the adsorption procedure of metal ions conforms to the pseudo-second-order model and langmuir model, respectively. The effective detection and the high adsorption of PNIPAAm-CD hydrogel for Fe 3+ make it an effective portable platform potential, which has the dual functions of visual detection and adsorption of Fe 3+ .
研究领域:
材料科学
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环境科学
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分析化学
✓ 已验证
产品关联
DOI
高影响因子
Polymers
·
2020
·Vol. 12
·期 3
·547
·
IF 3.426
Jiachang Feng,Jianpeng Dou,Youzhen Zhang,Zidan Wu,Dongxue Yin,Wenfu Wu
Starch, alginate, and poly(N-isopropylacrylamide) (PNIPAAm) were combined to prepare a semi-interpenetrating network (IPN) hydrogel with temperature sensitivity. Calcium chloride was used as cross-linking agent, the non-toxigenicAspergillus flavusspores were successfully encapsulated as biocontrol agents by the method of ionic gelation. Characterization of the hydrogel was performed by Fourier-transform infrared spectroscopy (FTIR), scanning electron micrograph (SEM), and thermogravimetry analysis (TGA). Formulation characteristics, such as entrapment efficiency, beads size, swelling behavior, and rheological properties were evaluated. The optical and rheological measurements indicated that the lower critical solution temperature (LCST) of the samples was about 29–30 °C. TGA results demonstrated that the addition of kaolin could improve the thermal stability of the semi-IPN hydrogel. Morphological analysis showed a porous honeycomb structure on the surface of the beads. According to the release properties of the beads, the semi-IPN hydrogel beads containing kaolin not only have the effect of slow release before peanut flowering, but they also can rapidly release biocontrol agents after flowering begins. The early flowering stage of the peanut is the critical moment to apply biocontrol agents. Temperature-sensitive hydrogel beads containing kaolin could be considered as carriers of biocontrol agents for the control of aflatoxin in peanuts.Keywords:thermosensitive;biocontrol;aflatoxin;PNIPAAm;encapsulation
研究领域:
农业科学
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食品科学
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微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Polymers
·
2024
·Vol. 16
·期 3
·416
·
IF 4.7
Tong Ji,Yuan Ji,Xiangli Meng,Qi Wang
Temperature-responsive separation membranes can significantly change their permeability and separation properties in response to changes in their surrounding temperature, improving efficiency and reducing membrane costs. This study focuses on the modification of polyvinylidene fluoride (PVDF) membranes with amphiphilic temperature-responsive copolymer and inorganic nanoparticles. We prepared an amphiphilic temperature-responsive copolymer in which the hydrophilic poly(N-isopropyl acrylamide) (PNIPAAm) was side-linked to a hydrophobic polyvinylidene fluoride (PVDF) skeleton. Subsequently, PVDF-g-PNIPAAm polymer and graphene oxide (GO) were blended with PVDF to prepare temperature-responsive separation membranes. The results showed that temperature-responsive polymers with different NIPAAm grafting ratios were successfully prepared by adjusting the material ratio of NIPAAm to PVDF. PVDF-g-PNIPAAm was blended with PVDF with different grafting ratios to obtain separate membranes with different temperature responses. GO and PVDF-g-PNIPAAm formed a relatively stable hydrogen bond network, which improved the internal structure and antifouling performance of the membrane without affecting the temperature response, thus extending the service life of the membrane.
研究领域:
材料科学
·
环境工程
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Nanomaterials
·
2022
·Vol. 12
·期 5
·777
·
IF 5.719
Pei Zhou,Nirmal Goswami,Tiankai Chen,Xiaoman Liu,Xin Huang
The research of aggregation-induced emission (AIE) has been growing rapidly for the design of highly luminescent materials, as exemplified by the library of AIE-active materials (or AIEgens) fabricated and explored for diverse applications in different fields. Herein, we reported a relay luminescence enhancement of luminescent Au nanoclusters (Au NCs) through AIE. In addition, we demonstrated the emergence of reduced aggregation-caused luminescence by adjusting the temperature of the Au NC solution. The key to induce this effect is to attach a thermosensitive polymer poly(N-isopropylacrylamide) (PNIPAAm) on the surface of Au NCs, which will shrink at high temperature. More interestingly, the as-synthesized Au NCs-PNIPAAm can self-assemble into vesicles, resulting in an obvious decrease in the luminescence intensity in aqueous solution. The combination of relay luminescence enhancement (by AIE) and luminescence decrease (induced by thermosensitive polymers) will be beneficial to the understanding and manipulation of the optical properties of Au NCs, paving the way for their practical applications.
研究领域:
材料科学
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光学
·
纳米技术
✓ 已验证
DOI
高影响因子
Food Chemistry-X
·
2026
·
IF 9.2
Xiaoxue Lu,Jingna Liu,Yuanhong Zhuang,Bingli Wang,Peng Fei,Wenqiang Lai
A series of thermo-responsive PNIPAAm-CS/SA composite hydrogel films were synthesized via radical polymerization and ionic cross-linking. FTIR, XPS, and NMR confirmed the successful covalent grafting of PNIPAAm onto the chitosan (CS) backbone. XRD and SSNMR analyses revealed that the grafting disrupted the CS crystalline regions, inducing an amorphous structural transition. The PNIPAAm-CS copolymer solutions exhibited LCST values in the range of 30–32 °C. Notably, compared with the corresponding precursor systems, the hydrated films exhibited an apparent thermo-responsive transition onset approximately 1 °C higher in temperature-dependent optical measurements, suggesting that film-network formation influenced the thermal response behavior of the PNIPAAm-containing system. Grafting modification significantly improved optical and mechanical properties: PNIPAAm-CS/SA-4 achieved a peak transmittance of 82.81% (vs. 50.78% for pure CS/SA), while PNIPAAm-CS/SA-2 reached an optimal balance with 22.6 MPa tensile strength and ∼ 100% elongation. Furthermore, antibacterial evaluation of the PNIPAAm-CS copolymers showed that, although the inhibitory activity decreased with increasing PNIPAAm incorporation, measurable antibacterial effects against E. coli and S. aureus were retained. Together with the preliminary package-integrated visual response demonstration, these results suggest that the hydrated films may serve as candidate temperature-responsive indicator materials for further development in intelligent packaging.
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
·
2022
·
IF 8.025
Guoguang Chen,Yaxin Zhou,Jie Dai,Shiyu Yan,Wenjun Miao,Lili Ren
Deep burns often do not heal easily, because the dermis of the skin is severely damaged, leading to severe inflammation and bacterial infection. Therefore, it is of great clinical significance to develop a dressing that promotes the healing process of deep burn wound. In this study, we used N-isopropyl acrylamide, sodium alginate and calcium chloride as the main materials, a series of calcium alginate/ poly (N-isopropyl acrylamide)(NIPAAm) hydrogel (CAPH) with different component ratios were synthesized. Its swelling properties, temperature response properties, rheological properties, biocompatibility properties, and in vitro drug release properties were investigated. Based on the above conditions, the CAPH(sodium alginate:NIPAAm = 2:15) with the best comprehensive performance was selected, which has a good biocompatibility. In addition, 0.02 % ( w / v ) mupirocin was loaded in CAPH. The temperature-responsive property of PNIPAAm in CAPH at 34 °C not only allowed the CAPH to rapidly release the drug under to prevent infection, but also to assist in wound contraction. Application of CAPH to localized wounds of deep second-degree burns in mice showed a faster healing rate and tissue regeneration. At the same time, collagen recovery was enhanced, collagen bundles were arranged in an orderly manner, and the scarring was not obvious after 16 days. Therefore, this research prepared a new safe and effective biomaterial.
研究领域:
材料科学
·
生物医学工程
·
伤口愈合
·
药学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CARBOHYDRATE POLYMERS
·
2012
·
IF 3.628
Xiaoyun Qiu,Xueqin Ren,Shuwen Hu
An independently temperature- and pH-responsive membrane was developed by simultaneously grafting poly( N -isopropylacryamide) (PNIPAAm) and poly[(2-(diethylamino)ethyl methacrylate] (PDEAEMA) from different sides of a crosslinked cellulose membrane. The synthesis was simplified by using surface-initiated activators regenerated by electron transfer for atom-transfer radical polymerization in a diffusion device. The grafted membrane was heterostructured. The grafted polymer layer thickness was linearly related to reaction time. The wettabilities of the double-membrane sides responded individually and reversibly to temperature and pH. The surface grafted with PNIPAAm shifted from hydrophilicity to hydrophobicity above the lower critical solution temperature. The PDEAEMA side was hydrophilic in acidic aqueous solution and hydrophobic under basic conditions. This dual-response cellulose membrane has potential applications in water treatment, separations, and other membrane applications.
研究领域:
材料科学
·
化学工程
·
膜技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）