共查询到20条相似文献,搜索用时 15 毫秒
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Qiangbing Wei Xiaowei Pei Junying Hao Meirong Cai Feng Zhou Weimin Liu 《Advanced Materials Interfaces》2014,1(5)
Diamond‐like carbon (DLC) film has emerged as a promising material for biomedical applications, but its low tribological properties in air could not be adapted in water and biological fluids. Herein, mussel‐inspired catechol adhesive is presented to functionalize DLC film and then polymer brushes are grafted by surface initiated atom transfer radical polymerization (SI‐ATRP) to mimic excellent biological lubrication of articular cartilage. Macroscopic tribological evaluation demonstrates low and stable friction coefficient of polymer brushe modified DLC film in water and biological fluids when sliding with a soft polydimethylsiloxane (PDMS) hemisphere, owing to viscous fluid‐like boundary lubricant film being formed by high hydration of polymer chains. The strong adhesive capability of catechol anchors also prevents polymer chains being sheared off from the substrate during friction tests. The friction responsiveness of PSPMA brushes is observed in electrolyte solution due to the conformation change of polymer chains. The successful functionalization of DLC with polymer brushes affords DLC film excellent biological lubrication and thus will broaden the scope of its applications in biomedical field. 相似文献
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Roland Gröger Tobias Heiler Thomas Schimmel Stefan Walheim 《Small (Weinheim an der Bergstrasse, Germany)》2023,19(29):2204962
Patterned, ultra-thin surface layers can serve as templates for positioning nanoparticlesor targeted self-assembly of molecular structures, for example, block-copolymers. This work investigates the high-resolution, atomic force microscopebased patterning of 2 nm thick vinyl-terminated polystyrene brush layers and evaluates the line broadening due to tip degradation. This work compares the patterning properties with those of a silane-based fluorinated self-assembled monolayer (SAM), using molecular heteropatterns generated by modified polymer blend lithography (brush/SAM-PBL). Stable line widths of 20 nm (FWHM) over lengths of over 20000 µm indicate greatly reduced tip wear, compared to expectations on uncoated SiOx surfaces. The polymer brush acts as a molecularly thin lubricating layer, thus enabling a 5000 fold increase in tip lifetime, and the brush is bonded weakly enough that it can be removed with surgical accuracy. On traditionally used SAMs, either the tip wear is very high or the molecules are not completely removed. Polymer Phase Amplified Brush Editing is presented, which uses directed self-assembly to amplify the aspect ratio of the molecular structures by a factor of 4. The structures thus amplified allow transfer into silicon/metal heterostructures, fabricating 30 nm deep, all-silicon diffraction gratings that could withstand focused high-power 405 nm laser irradiation. 相似文献
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Ke He Zhiyuan Liu Changjin Wan Ying Jiang Ting Wang Ming Wang Feilong Zhang Yaqing Liu Liang Pan Meng Xiao Hui Yang Xiaodong Chen 《Advanced materials (Deerfield Beach, Fla.)》2020,32(24):2001130
On-skin flexible devices provide a noninvasive approach for continuous and real-time acquisition of biological signals from the skin, which is essential for future chronic disease diagnosis and smart health monitoring. Great progress has been achieved in flexible devices to resolve the mechanical mismatching between conventional rigid devices and human skin. However, common materials used for flexible devices including silicon-based elastomers and various metals exhibit no resistance to epidermal surface lipids (skin oil and grease), which restricts the long-term and household usability. Herein, an on-skin electrode with anti-epidermal-surface-lipid function is reported, which is based on the grafting of a zwitterionic poly(2-methacryl-oyloxyethyl, methacryloyl-oxyethyl, or meth-acryloyloxyethyl phosphorylcholine) (PMPC) brush on top of gold-coated poly(dimethylsiloxane) (Au/PDMS). Such an electrode allows the skin-lipids-fouled surface to be cleaned by simple water rinsing owing to the superhydrophilic zwitterionic groups. As a proof-of-concept, the PMPC-Au/PDMS electrodes are employed for both electrocardiography (ECG) and electromyography (EMG) recording. The electrodes are able to maintain stable skin-electrode impedance and good signal-to noise ratio (SNR) by water rinsing alone. This work provides a material-based solution to improve the long-term reusability of on-skin electronics and offers a unique prospective on developing next generation wearable healthcare devices. 相似文献
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Polymer Brushes: Mussel‐Inspired Polymer Carpets: Direct Photografting of Polymer Brushes on Polydopamine Nanosheets for Controlled Cell Adhesion (Adv. Mater. 7/2016) 下载免费PDF全文
Daniel Hafner Lisa Ziegler Muhammad Ichwan Tao Zhang Maximilian Schneider Michael Schiffmann Claudia Thomas Karsten Hinrichs Rainer Jordan Ihsan Amin 《Advanced materials (Deerfield Beach, Fla.)》2016,28(7):1330-1330
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Mussel‐Inspired Polymer Carpets: Direct Photografting of Polymer Brushes on Polydopamine Nanosheets for Controlled Cell Adhesion 下载免费PDF全文
Daniel Hafner Lisa Ziegler Muhammad Ichwan Tao Zhang Maximilian Schneider Michael Schiffmann Claudia Thomas Karsten Hinrichs Rainer Jordan Ihsan Amin 《Advanced materials (Deerfield Beach, Fla.)》2016,28(7):1489-1494
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Xingyu Chen Zaifu Lin Ying Feng Hong Tan Xinyuan Xu Jun Luo Jianshu Li 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(42)
Biodegradable polycaprolactone (PCL) has been widely applied as a scaffold material in tissue engineering. However, the PCL surface is hydrophobic and adsorbs nonspecific proteins. Some traditional antifouling modifications using hydrophilic moieties have been successful but inhibit cell adhesion, which is not ideal for tissue engineering. The PCL surface is modified with bioinspired zwitterionic poly[2‐(methacryloyloxy)ethyl choline phosphate] (PMCP) via surface‐initiated atom transfer radical polymerization to improve cell adhesion through the unique interaction between choline phosphate (CP, on PMCP) and phosphate choline (PC, on cell membranes). The hydrophilicity of the PCL surface is significantly enhanced after surface modification. The PCL‐PMCP surface reduces nonspecific protein adsorption (e.g., up to 91.7% for bovine serum albumin) due to the zwitterionic property of PMCP. The adhesion and proliferation of bone marrow mesenchymal stem cells on the modified surface is remarkably improved, and osteogenic differentiation signs are detected, even without adding any osteogenesis‐inducing supplements. Moreover, the PCL‐PMCP films are more stable at the early stage of degradation. Therefore, the PMCP‐functionalized PCL surface promotes cell adhesion and osteogenic differentiation, with an antifouling background, and exhibits great potential in tissue engineering. 相似文献
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Construction of 3D Polymer Brushes by Dip‐Pen Nanodisplacement Lithography: Understanding the Molecular Displacement for Ultrafine and High‐Speed Patterning 下载免费PDF全文
Chaojian Chen Xuechang Zhou Zhuang Xie Tingting Gao Zijian Zheng 《Small (Weinheim an der Bergstrasse, Germany)》2015,11(5):613-621
Dip‐pen nanodisplacement lithography (DNL) is a versatile scanning probe‐based technique that can be employed for fabricating ultrafine 3D polymer brushes under ambient conditions. Many fundamental studies and applications require the large‐area fabrication of 3D structures. However, the fabrication throughput and uniformity are still far from satisfactory. In this work, the molecular displacement mechanism of DNL is elucidated by systematically investigating the synergistic effect of z extension and contact time. The in‐depth understanding of molecular displacement results in the successful achievement of ultrafine control of 3D structures and high‐speed patterning at the same time. Remarkably, one can prepare arbitrary 3D polymer brushes on a large area (1.3 mm × 1.3 mm), with <5% vertical and lateral size variations, and a patterning speed as much as 200‐fold faster than the current state‐of‐the‐art. 相似文献
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Jin Zhou Xue‐Feng Cheng Bi‐Jun Gao Chuang Yu Jing‐Hui He Qing‐Feng Xu Hua Li Na‐Jun Li Dong‐Yun Chen Jian‐Mei Lu 《Small (Weinheim an der Bergstrasse, Germany)》2019,15(2)
Nitrogen dioxide (NO2) emission has severe impact on human health and the ecological environment and effective monitoring of NO2 requires the detection limit (limit of detection) of several parts‐per‐billion (ppb). All organic semiconductor‐based NO2 sensors fail to reach such a level. In this work, using an ion‐in‐conjugation inspired‐polymer (poly(3,3′‐diaminobenzidine‐squarine, noted as PDBS) as the sensory material, NO2 can be detected as low as 1 ppb, which is the lowest among all reported organic NO2 sensors. In addition, the sensor has high sensitivity, good reversibility, and long‐time stability with a period longer than 120 d. Theoretical calculations reveal that PDBS offers unreacted amine and zwitterionic groups, which can offer both the H‐bonding and ion‐dipole interaction to NO2. The moderate binding energies (≈0.6 eV) offer high sensitivity, selectivity as well as good reversibility. The results demonstrate that the ion‐in‐conjugation can be employed to greatly improve sensitivity and selectivity in organic gas sensors by inducing both H‐bonding and ion‐dipole attraction. 相似文献
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Mie Lillethorup Mikkel Kongsfelt Marcel Ceccato Bjarke B. E. Jensen Bjarke Jørgensen Steen U. Pedersen Kim Daasbjerg 《Small (Weinheim an der Bergstrasse, Germany)》2014,10(5):922-934
Electrografting using aryldiazonium salts provides a fast and efficient technique to functionalize commercially available 3?5 layered graphene (vapour‐deposited) on nickel. In this study, Raman spectroscopy is used to quantify the grafting efficiency of cyclic voltammetry which is one of the most versatile, yet simple, electrochemical techniques available. To a large extent the number of defects/substituents introduced to the basal plane of high‐quality graphene by this procedure can be controlled through the sweeping conditions employed. After extended electrografting the defect density reaches a saturation level (~1013 cm?2) which is independent of the quality of the graphene expressed through its initial content of defects. However, it is reached within fewer voltammetric cycles for low‐quality graphene. Based on these results it is suggested that the grafting occurs (a) directly at defect sites for, in particular, low‐quality graphene, (b) directly at the basal plane for, in particular, high‐quality graphene, and/or (c) at already grafted molecules to give a mushroom‐like film growth for all films. Moreover, it is shown that a tertiary alkyl bromide can be introduced at a given surface density to serve as radical initiator for surface‐initiated atom transfer radical polymerization (SI‐ATRP). Brushes of poly(methyl methacrylate) are grown from these substrates, and the relationship between polymer thickness and sweeping conditions is studied. 相似文献
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Jelani Griffin Anant Kumar Singh Dulal Senapati Eumin Lee Kevin Gaylor Jeanette Jones‐Boone Paresh Chandra Ray 《Small (Weinheim an der Bergstrasse, Germany)》2009,5(7):839-845
The hepatitis C virus (HCV) is a single‐stranded (ss) RNA virus that is responsible for chronic liver diseases, such as cirrhosis, end‐stage liver disease, and hepatocellular carcinoma. Driven by the need to detect the presence of the HCV viral sequence, herein it is demonstrated for the first time that the nonlinear optical (NLO) properties of gold nanoparticles can be used for screening and quantifying HCV RNA without any modification, with excellent detection limit (80 pM ) and selectivity (single base‐pair mismatch). The hyper‐Rayleigh scattering (HRS) intensity increases 25 times when label‐free, 145‐mer, HCV ss‐RNA is hybridized with 400 pM target RNA. The mechanism of HRS intensity change is discussed with experimental evidence for a higher multipolar contribution to the NLO response of gold nanoparticles. 相似文献
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