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排序方式: 共有1379条查询结果,搜索用时 40 毫秒
71.
Synergistically taking the advantage of distinctive porous matrix, luminophore and functional nanoparticles, we prepared functional nanocomposite hydrogel combining the hydrophilic three-dimensional network of hydrogels as matrix for the adsorption of luminophore, Ru(bpy)32+, and in situ grown gold nanoparticles (AuNPs) as the conductive. Interestingly, the designed nanocomposite hydrogel shows external pressure resposnsive properties, which precisely tune the distance between the AuNPs becomes shorter, resulting in a remarkable amplification of electrochemiluminescence (ECL) signals. Additionally, differing from the poor stability of conventional ECL, uniform dispersion of the Ru(bpy)32+ over nanocomposite hydrogel significantly enhanced the long term stability of ECL. 相似文献
72.
Zhihui Pan Yingru Huang Haoyong Guo Tingjian Huang Gang Wen Huarong Yu Junguo He 《先进技术聚合物》2022,33(1):235-245
An advanced dual pH- and temperature-sensitive hydrogel (NASH2.5) was optimally synthesized through modification of N-isopropylacrylamide (NIPAM) hydrogel with introducing 5 mol% acrylic acid (AA) and 2.5 wt% sewage sludge ash (SSA). The swelling kinetic results showed that NASH2.5 exhibited both high equilibrium swelling ratio and swelling rate, which was attributed to the higher porous structure as shown in scanning electron microscope, and the more hydrogen bonding formed inside of the hydrogel as investigated in Fourier transform infrared spectrometer. In addition, its curve was better fitted to the pseudo-second-order model, indicating that the water absorption process was dominated by chemisorption through forming the hydrogen bonding among the water molecules and carboxyl/silanol groups of the hydrogel. Compared with the pure NIPAM hydrogel, the water transport mechanism switched from Case I diffusion to Case II diffusion by introduction of AA and further SSA. Furthermore, through the results of the deswelling kinetics in pH value change (from 9 to 4 and 2, respectively), temperature value change (from 25 to 40, 50, and 60°C, respectively), and dual pH and temperature values changes, NASH2.5 not only presented a high pH sensitivity, but also showed high sensitive to temperature by achieving high water recovery ratio in rapid dehydrated rate. Therefore, the dual stimuli-sensitive hydrogel with the simultaneously high performance of swelling and deswelling would provide a suitable alternative for specific applications such as pollutant adsorption. 相似文献
73.
Spatial structures break their symmetry under the influence of shear stress arising from fluid flow. Here, we present surface instabilities appearing on chitosan tubes when an acidic solution of chitosan with various molecular weight is injected into a pool of sodium hydroxide solution. At slow flow rates wrinkle-to-fold transition takes place along the direction of the flow yielding a banded structure. For greater injection rates we observe coexisting modes of wrinkles and folds which are stabilized to periodic wrinkles when the alkaline concentration is increased. The instabilities are characterized by the scaling laws of the pattern wavelength and amplitude with the tube characteristics. Our experimental adaptation of mechanical instabilities provides a new in situ method to create soft biomaterials with the desired surface morphology without the use of any prefabricated templates. 相似文献
74.
Martyna Zagrska-Dziok Tomasz Bujak Aleksandra Ziemlewska Zofia Nizio-ukaszewska 《Molecules (Basel, Switzerland)》2021,26(4)
The skin is an organ that is constantly exposed to many external factors that can affect its structure and function. Due to the presence of different cannabinoid receptors on many types of skin cells, cannabinoids can interact directly with them. Therefore, as part of this work, the impact of two types of Cannabis sativa L. herb extracts on keratinocytes and fibroblasts was assessed. The content of biologically active compounds such as phenols, flavonoids, chlorophylls and cannabinoids was evaluated. The antioxidant capacity of prepared extracts using the DPPH radical, H2DCFDA probe and measurement of superoxide dismutase activity was also assessed. The cytotoxicity of hemp extracts was determined using the Alamar Blue, Neutral Red and LDH assays. The ability of the extracts to inhibit the activity of matrix metalloproteinases, collagenase and elastase, was assessed. Preparations of model hydrogels were also prepared and their effect on transepidermal water loss and skin hydration was measured. The obtained results indicate that hemp extracts can be a valuable source of biologically active substances that reduce oxidative stress, inhibit skin aging processes and positively affect the viability of skin cells. The analysis also showed that hydrogels based on cannabis extracts have a positive effect on skin hydration. 相似文献
75.
金属有机框架(MOFs)具有大量的孔隙结构和活性位点,在气体吸附、催化、医疗等领域均发挥了巨大的作用。MOFs是晶体粉末,具有脆性较大、在水中易分解和不易回收等缺点,从而限制了其应用。通过MOFs与柔性高分子的复合,特别是与水凝胶的复合,极大地改善了复合材料的柔顺性、可回收和可加工性等特性,进一步拓宽了MOFs的应用领域。本文详细阐述了基于水凝胶MOFs原位生成法、MOFs /水凝胶同时生成法和水凝胶包裹MOFs法等三种不同方法制备MOFs/水凝胶复合材料的研究进展,并对上述三种制备方法的特点及其产物特征进行了总结,进一步归纳了复合材料在生物医药、催化、废水处理和气体吸附等领域的应用。最后,对MOFs/水凝胶复合材料制备方法的改进和复合材料应用前景进行了深入讨论和展望。 相似文献
76.
Farzad Seidi Wei-Feng Zhao Hui-Ning Xiao Yong-Can Jin Mohammad Reza Saeb Chang-Sheng Zhao 《高分子科学》2021,39(1):14-34
Surface design and engineering is a critical tool to improve the interaction of materials with their surroundings. Immobilization of soft hydrogels is one of the attractive strategies to achieve surface modification. The goal of this review is to provide a comprehensive overview of the different strategies used for surface tethering of hydrogel layers via crosslinking immobilization of pre-fabricated functional polymers. In this strategy, crosslinkable polymers are first prepared via various polymerization techniques or post-functionalization of polymers. Afterwards, the crosslinkable polymers are attached or tethered on the surfaces of substrates using a variety of approaches including photo-crosslinking, click reactions, reversible linkages, etc. For each case, the principles of hydrogel tethering have been explained in detail with representative examples.Moreover, the potential applications of the as-modified substrates in specific cases have also been addressed and overviewed. 相似文献
77.
Nanocomposite hydrogels are one of the most important types of biomaterials which can be used in many different applications such as drug delivery and tissue engineering.Incorporation of nanoparticles within a hydrogel matrix can provide unique characteristics like remote stimulate and improved mechanical strength.In this study,the synthesis of graphene oxide and graphene oxide nanocomposite hydrogel has been studied.Nanocomposite hydrogel was synthesized using carboxymethyl cellulose as a natural base,acrylic acid as a comonomer,graphene oxide as a filler,ammonium persulfate as an initiator,and iron nanoparticles as a crosslinking agent.The effect of reaction variables such as the iron nanoparticles,graphene oxide,ammonium persulfate,and acrylic acid were examined to achieve a hydrogel with maximum absorbency.Doxorubicin,an anti-cancer chemotherapy drug,was loaded into this hydrogel and its release behaviors were examined in the phosphate buffer solutions with different pH values.The structure of the graphene oxide and the optimized hydrogel were confirmed by Fourier-transform infrared spectroscopy,Raman spectroscopy,X-ray diffraction,scanning electron microscopy,and atomic force microscopy. 相似文献
78.
79.
针对纺织业中浮纹布的织造一直依赖纯机械控制的现状,为提高浮纹布织造的精度和效率,特设计了智能浮纹织造控制系统,通过上位机的工艺软件进行浮纹花色品种的设计,以U盘将多种浮纹工艺文件导入到浮纹织造控制系统里,以STM32处理器为核心根据浮纹工艺进行相关织造的电气控制。为了便于实时掌握浮纹布的产量并按订单及时进行品种的更换,系统以Zigbee技术实现数据的传输及命令的远程控制,避免了复杂的布线。经现场长时间运行,系统稳定可靠,织造速度可达250转/分以上,控制精度达到0.1mm,具有很好的应用价值。 相似文献
80.
Matthew Wallace Andre Zamith Cardoso Dr. William J. Frith Dr. Jonathan A. Iggo Dr. Dave J. Adams 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(50):16484-16487
The magnetic‐field‐induced alignment of the fibrillar structures present in an aqueous solution of a dipeptide gelator, and the subsequent retention of this alignment upon transformation to a hydrogel upon the addition of CaCl2 or upon a reduction in solution pH is reported. Utilising the switchable nature of the magnetic field coupled with the slow diffusion of CaCl2, it is possible to precisely control the extent of anisotropy across a hydrogel, something that is generally very difficult to do using alternative methods. The approach is readily extended to other compounds that form viscous solutions at high pH. It is expected that this work will greatly expand the utility of such low‐molecular‐weight gelators (LMWG) in areas where alignment is key. 相似文献