Soft Matter
·
2011
·Vol. 7
·期 16
·7526-7531
·
IF 4.457
Shengtong Sun,Peiyi Wu
Highly branched poly(N-isopropylacrylamide) (PNIPAM) was first synthesized by self-condensing atom transfer radical copolymerization (SCATRCP) catalyzed by CuBr/tris[2-(dimethylamino)ethyl]amine (Me6TREN) complex in isopropanol at room temperature. This method showed good control over chain morphology and lower critical solution temperature (LCST) type phase transition behavior of PNIPAM by varying reaction time and monomer/inimer feed ratios. On the basis of GPC, FTIR, 1HNMR and DSC results, four stages were discerned during the polymerization procedure, at which chain architectures experienced “linear – comblike – slightly branched – highly branched” transformations. Additionally, the synthesized highly branched PNIPAM chains were found to be able to self-assemble into hollow spheres in alcohols such as methanol and ethanol, which arise from the presence of large amounts of hydrophobic branched points inside polymer chains.
研究领域:
高分子化学
·
材料科学
·
物理化学
✓ 已验证
产品关联
DOI
高影响因子
TALANTA
·
2021
·
IF 6.057
Pengcheng Ma,Xiaoyan Ma
In this work, based on the dual catalytic properties of copper (Cu) particles for methanol oxidation and persulfate initiated radical polymerization , a temperature-controlled catalytic electrode, defined the PNIPAM-Cu@CP, was constructed by electrodepositing Cu particles on a carbon paper electrode and triggering the polymerization of the temperature-sensitive polymer N-isopropylacrylamide (PNIPAM) on the surface of the electrode, which is expected to be applicated in the micro-direct methanol fuel cell (DMAC) for detection of methanol crossover and also has temperature recognition and high-temperature self-protection functions. Cu particles and PNIPAM were characterized by X-ray diffraction (XRD), fourier-transform infrared spectroscopy (FT-IR) and scanning electron microscopy (SEM) for their specific structure and morphology. The cyclic voltammetry (CV) results showed the proposed electrode as a temperature-controlled switch-like methanol sensor, has a wide linear range (1–300 mM and 300–1200 mM), excellent sensitivity (72.8 μA cm −2 mM −1 and 11.5 μA cm −2 mM −1 ) and a low detection limit of 0.3 mM for methanol. In addition, the sensor also has excellent selectivity and temperature-triggered switchable electrocatalytic activity . The efficient and simple preparation method of the electrode is expected to be used in the development of a methanol sensor for real-time methanol detection in micro-DMAC.
研究领域:
材料科学
·
电化学
·
传感技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
KEY ENGINEERING MATERIALS
·
2015
·
IF 0
Shu Lin Guan,Na Fan,Qi Zhong,Ji Ping Wang
Thermo-responsive microgels with core-shell structure were prepared by free radical emulsion polymerization. The core of microgels was consisted of poly (N-isopropyl acrylamide) (PNIPAM), while the shell was consisted of poly (ethylene glycol) methyl ether methacrylate (POEGMA300). In order to compare the transition behavior of the core-shell microgels with the microgels consisted of one thermo-responsive microgel, PNIPAM and POEGMA300 microgels were prepared. PNIPAM exhibits a lower critical solution temperature (LCST) of 32 °C, and the LCST of POEGMA300 is approximately 63 °C. The thermo-responsive microgel behavior was measured by dynamic light scattering (DLS). It is observed that both of PNIPAM and POEGMA300 microgels show a thermo-responsive ability. The particle size significantly drops when the temperature passes LCST. Moreover the particle size of the thermo-responsive microgels with core (PNIPAM)-shell (POEGMA300) structure shows a linear transition behavior when the temperature is between 50 °C and 70 °C.
研究领域:
材料科学
·
高分子化学
✓ 已验证
DOI
WATER RESEARCH
·
2024
·
IF 11.4
Hongzhi Liu,Zi Wang,Hesong Wang,Zihan Liu,Jiaxuan Yang,Han Zhang,Heng Liang,Langming Bai
To address the issues of scaling caused by heat and water evaporation in regard to circulating cooling water (CCW), TFC membrane filtration systems have been increasingly considered for terminal treatment processes because of their excellent separation performance. However, membrane biofouling phenomenon significantly hinders the widespread utilization of TFC membranes. In this study, to harness the thermal phenomenon of CCW and establish a stable and durable multifunctional antibiofouling layer, temperature-responsive Pnipam and the spectral antibacterial agent Ag were organically incorporated into commercially available TFC membranes. Biological experimental findings demonstrated that above the lower critical solution temperature (LCST), the contraction of Pnipam molecular chains facilitated the inactivation of bacteria by the antibacterial agent, resulting in an impressive sterilization efficiency of up to 99 %. XDLVO analysis revealed that below the LCST, the establishment of a hydration layer on the functional interface resulted in the creation of elevated energy barriers, effectively impeding bacterial adhesion to the membrane surface. Consequently, a high bacterial release rate of 98.4 % was achieved on the low-temperature surface. The alterations in the functional membrane surface conformation induced by temperature variations further amplified the separation between the pollutants and the membrane, creating an enhanced "elastic interface." This efficient and straightforward cleaning procedure mitigated the formation of irreversible fouling without compromising the integrity of the membrane surface. This study presents a deliberately engineered thermoresponsive antibiofouling membrane interface to address the issue of membrane fouling in membrane-based CCW treatment systems while shedding new light on the mechanisms of "inactivation" and "defense."
研究领域:
环境科学
·
材料科学
·
微生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
MACROMOLECULES
·
2012
·
IF 5.167
Chuanzhuang Zhao,Guangcui Yuan,Charles C. Han
Poly(N-isopropylacrylamide) (PNIPAM) microgels are adsorbable to the surface of polystyrene (PS) microspheres in the experimental temperature range (25–40 °C) and can induce aggregation of microspheres through the bridging mechanism. The bridging mechanism proceeds in two elementary steps: the first is an adsorption (negligible desorption relatively) of free microgel to one microsphere surface, and the next is a reversible connection of the adsorbed microgel to another microsphere surface. The surface coverage is found as an important factor in triggering the stabilization, aggregation, and gelation of the mixtures. And most importantly, the nonnegligible dynamic disconnection of a bridge is the essential prerequisite for structure or state transition. For mixtures with the same concentration of microsphere, depending on the concentration of microgel, various transitions can be induced by changing temperature, including the transition from a weaker gel to a stronger gel, from a fluid to a bridging gel and from a depletion gel to a bridging gel.
研究领域:
材料科学
·
胶体化学
✓ 已验证
DOI
高影响因子
ACS Applied Polymer Materials
·
2025
·
IF 4.7
Yunhao Bao,Xiangrui Guo,Jiabao Zheng,Pinghou Sheng,Shilong Wang,Tianyi Wang,Yingcai Wu,Ziyuan Liu,Yun Ding
Color-changing materials make up a category of smart materials capable of exhibiting chromatic transitions in response to environmental stimuli. Certain thermochromic materials exhibit tunable optical transmittance during chromatic transitions, allowing for dynamic modulation of solar radiation in energy-efficient window applications. In this work, we develop a low-cost thermochromic poly(N-isopropylacrylamide)/carboxymethyl cellulose sodium/poly(ethylene glycol) (PCP) composite, achieving excellent light modulation and indoor temperature regulation capabilities. The introduction of CMC and PEG significantly enhanced the uniform dispersion of PNIPAM, thereby endowing the material with a highly efficient transition from transparent to opaque. Meanwhile, the results show that the PNIPAM/CMC/PEG smart window has high luminous modulation (ΔTlum = 99.20%) with approximately 100% luminous transmission (Tlum = 99.29%) at 25 °C and approximately 0% transmission (Tlum = 0.09%) at 35 °C. Additionally, the smart window demonstrated long-term stability in dynamic transparent–opaque transitions and a low transition temperature of 30.9 °C. Therefore, the proposed composite presents several advantages, including high efficiency, low cost, and easy scalability, offering new insights into the design and fabrication of smart windows and other smart materials.
研究领域:
材料科学
·
智能材料
·
节能建筑
·
聚合物复合材料
·
光学器件
✓ 已验证
产品关联
DOI
高影响因子
Regenerative Biomaterials
·
2023
·
IF 6.7
Cao Yu,Wang Longfei,Zhang Xiumei,Lu Yi,Wei Yan,Liang Ziwei,Hu Yinchun,Huang Di
Rapid post-wound closure is necessary to avoid wound infection and promote scar-free healing when skin trauma occurs. In this study, new types of hydrogel dressings with adjustable contractility were fabricated based on N-isopropyl acrylamide/sodium alginate/graphene oxide (P/SA/GO). Then, the chitosan (CS) solution was used as a bridging polymer to achieve tissue adhesion to the hydrogel. The results show that the hydrogel based on poly(N-isopropyl acrylamide) (PNIPAM) not only has the ability to self-shrink but also can adjust the rate of shrinkage through near-infrared thermal stimulation. At the same time, high adhesion strength (7.86 ± 1.22 kPa) between the tissue and the dressing is achieved through the introduction of bridging polymers (CS), and the coating area of the bridging polymer can be adjusted to achieve regional adhesion. The mouse total skin defects experiments have shown that sutures-free wound closure in the early stages of wound healing could be obtained by adjusting the material temperature. Besides, the dressings can promote scar-free wound healing by reducing inflammatory cell infiltration and collagen deposition. These results indicate that double-crosslinked PNIPAM-based hydrogel dressings with adjustable adhesion and contractility proposed in this study provide a candidate material for achieving trackless wound healing.
研究领域:
材料科学
·
生物医学工程
·
伤口愈合
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Soft Matter
·
2020
·Vol. 16
·期 12
·3063-3068
·
IF 3.14
Chunfang Li,Qihao Xue,Zhaoyang Ji,Yaxia Li,Hongyan Zhang,Dongxiang Li
Photonic crystals (PCs) are periodic dielectric structures with photonic bandgaps and they can be used to control and manipulate photons effectively. Novel photonic crystal materials with tunable bandgaps can be prepared by changing the refractive index of the dielectric or lattice parameters under external stimuli, while using temperature to adjust the photonic band gap is a simple and convenient method. In this paper, silica PCs having different pseudo-gaps in the range of 450–750 nm were prepared with colloidal SiO2 spheres of different sizes. Thermo-sensitive PNIPAM hydrogel was then infiltrated into the PCs to obtain PNIPAM-PCs, whose pseudo-gap blue-shifted when the temperature was changed from 24 to 34 °C and exhibited good reversibility. The PCs with tunable bandgaps are significant for the development of integrated photonic devices, sensors, and in detection and other technologies.
研究领域:
材料科学
·
光学工程
✓ 已验证
DOI
高影响因子
BIOMACROMOLECULES
·
2018
·
IF 5.738
Wangmeng Hou,Lin Wei,Li Liu,Hanying Zhao
Well-defined polymer–protein bioconjugates are widely used in therapeutics and biocatalysis. One of the challenges in the synthesis of bioconjugates is the efficient separation of the target conjugate molecules from reaction systems. In this research, surface coassembly of polymer brushes and polymer–protein bioconjugates is investigated, and it is demonstrated that the coassembly approach can be applied in the purification of polymer–protein bioconjugates. Bovine serum albumin-poly(N-isopropylacrylamide) (BSA-PNIPAM) bioconjugates were synthesized by the “grafting from” approach, and PNIPAM brushes on silica particles were prepared by the “grafting to” approach. PNIPAM brushes on silica particles are able to coassemble with BSA-PNIPAM at a temperature above the lower critical solution temperature of PNIPAM. Two-layer surface structures with collapsed PNIPAM in the inner layers and BSA in the outer layers are formed on the silica particles. The size of the silica particles and molecular weight of PNIPAM on the bioconjugates exert influences on the coassembly. The coassembly approach can be used in the purification of bioconjugates. After repeated coassembly centrifugation-release cycles, all the BSA-PNIPAM bioconjugates can be removed from the reaction solutions, and the purified bioconjugates are obtained.
研究领域:
材料科学
·
生物化学
·
分子生物学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2015
·
IF 4.529
Zailin Gong,Shujin Li,Jun Ma,Xiangdong Zhang
The commercial powdered activated carbon (PAC) has been selectively oxidized by two methods. The two oxidized methods are wet oxidation with ammonium persulfate and thermal treatment after acidification with hydrochloride acid, respectively. The two oxidized PAC were then functionalized with thermoresponsive poly ( N -isopropylacrylamide) (PNIPAM) in aqueous solution at ambient temperature. Comparing the two oxidized PAC products and their grafted derivatives, the oxidized PAC modified with thermal treatment after acidification shows larger surface area of 1184 m 2 /g and better adsorption of bisphenol A. Its derivative also exhibits relatively large surface area and adsorption capacity after grafted with PNIPAM. The maximum surface adsorption capacity simulated under Langmuir Models reached 156 mg/g. In addition, the grafted PAC products show self-flocculation behaviors with rapid response to temperature because of the thermal phase transition and entanglement behaviors of PNIPAM. The present study provides a new way to obtain carboxyl-rich activated carbon with large surface area and better adsorption capacity. The retrievable grafted PAC with good self-flocculation effect responsive to temperature will have high potential application in water remediation which requires pre-heating and emergency water treatment in the wild.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
JOURNAL OF MEMBRANE SCIENCE
·
2025
·
IF 9
Kaili Jin,Liujun Pei,Zaisheng Cai,Yudie Zhou,Xiner Zhang,Yaping Zhao,Hongjuan Zhang,Qun Yang,Shuaitong Liang,Jiping Wang
Smarting gating microfiltration membranes that can adjust the pore size according to the composition of the wastewater are expected to solve the problem of membrane's limited adaptability to complex oily wastewater. However, the design of a responsive adjustment system capable of manipulating micropore sizes and constant wettability remains a dilemma. Herein, an innovative fiber-based membrane (named PAN/PNIPAm-CF/MWCNT/FeOOH) was developed by skillful introducing poly (n-isopropylacrylamide) (PNIPAm) microgels into the porous channel of the sieve layer. By controlling the physical collapse of PNIPAm microgels, the micro-sized pores have been successfully reversibly adjusted from small size at room temperature to large size when exposed to high temperature, while not changing their wettability. Under a flux conversion rate of more than 200 %, the PAN/PNIPAm-CF/MWCNT/FeOOH membrane could quickly pretreat complex oily wastewater discharged from production lines with high temperature (removal of large oil droplets), then carry out in-depth purification at low temperature (removal of emulsified oils, metal ions, dye micelles, etc.). Besides, the PAN/PNIPAm-CF/MWCNT/FeOOH membrane showed good stability and resistance to harsh environment during long-term filtration. Thereby, the design of fiber-based membranes with micropore smart control capability and constant wettability provides innovative ideas for industrial complex oily wastewater treatment.
研究领域:
环境科学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
LANGMUIR
·
2022
·
IF 4.331
Xiaoyuan Ji,Qian Lu,Xuhao Sun,Liyun Zhao,Yuhan Zhang,Jinshui Yao,Xian Zhang,Hui Zhao
As a nanozyme, gold nanoparticles have some advantages compared with natural enzymes, such as stable structure, adjustable catalytic activity, multifunctionality, and recyclability. Due to their special dimension, they are easy to aggregate rapidly and lose their catalytic performance when exposed to normal saline or special pH environment. To avoid such a situation, Au@PNIPAm nanozymes with core–shell structure are constructed and their mimic peroxidase and glucose oxidase enzymatic activities are investigated. Kinetic examinations manifest that Au@PNIPAm nanozymes exhibited a high affinity for 3,3,5,5-tetramethylbenzidine (TMB), hydrogen peroxide (H2O2), and glucose. These predominant peroxidase-like and glucose-like oxidase Au@PNIPAm catalytic activities are successfully used in the detection of H2O2 or glucose (LOD is 2.43 mM or 5.07 mM). Otherwise, the potential Au@PNIPAm nanozymes are provided with a clear ability for decomposing the intracellular H2O2 in living cells. And it could protect cells from oxidative stress damage with inducing by H2O2. Therefore, it is easy to consider that Au@PNIPAm nanozymes show a certain possibility to retard cell senescence and increase the production of the hydroxyl radical which could prevent carcinogenesis of the cell.
研究领域:
纳米技术
·
酶模拟
·
生物传感器
·
活性氧生物学
·
生物医学工程
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）