RF plasma polymer modification of graphene oxide for micromotors with improved performance

Graphene oxide (GO)-modified polypyrrole (PPy) coatings were obtained by electrochemical methods in the presence of the anionic surfactant, sodium dodecyl sulfate (SDS). The structure, morphology, and electrochemical properties of the coatings were assessed by Fourier transform infrared (FTIR) spectroscopy, Raman spectroscopy, scanning electron microscopy (SEM) and cyclic voltammetry at varying scan rates, respectively. The properties of the obtained coatings were analyzed with the GO and PPy loadings and electrodeposition mode. The hybrid coatings obtained galvanostatically showed a coarser appearance than those deposited by cyclic voltammetry CV mode and improved performance, respectively, which was further enhanced by GO and PPy loading. The capacitance enhancement can be attributed to the SDS surfactant that well dispersed the GO sheets, thus allowing the use of lower GO content for improved contribution, while the choice of suitable electrodeposition parameters is highly important for improving the applicability of GO-modified PPy coatings in energy storage applications.

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Improved Performance of DSSC Photoanodes After the Modification of TiO2 with Reduced Graphene Oxide

Journal of Electronic Materials ◽

10.1007/s11664-020-08642-5 ◽

2021 ◽

Author(s):

D. S. U. Peiris ◽

Piyasiri Ekanayake ◽

B. A. Karunaratne ◽

Mohammad Iskandar Petra

Keyword(s):

Graphene Oxide ◽

Reduced Graphene Oxide ◽

Reduced Graphene ◽

Improved Performance

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Surface Immobilization of Synthetic Proteins Via Plasma Polymer Interlayers

MRS Proceedings ◽

10.1557/proc-544-9 ◽

1998 ◽

Vol 544 ◽

Cited By ~ 6

Author(s):

Hans J Griesser ◽

Keith M McLean ◽

Gerrit J Beumer ◽

Xiaoyi Gong ◽

Peter Kingshot ◽

...

Keyword(s):

Carboxylic Acid ◽

Cell Attachment ◽

Plasma Layer ◽

Polymeric Materials ◽

Covalent Immobilization ◽

Biologically Active ◽

Plasma Polymer ◽

Rf Plasma ◽

Bulk Materials ◽

Synthetic Proteins

AbstractCoatings of biologically active molecules on synthetic ”bulk“materials are of much interest for biomedical applications since they can in principle elicit specific, predictable. controlled responses of the host environment to an implanted device. However, issues such as shelf life. storage conditions, biological safety, and enzymatic attack in the biological environment must be considered; synthetic proteins may offer advantages. In this study we investigated the covalent immobilization onto polymeric materials of synthetic proteins which possess some properties that mimic those of the natural protein collagen, particularly the ability to form triple helical structures, and thus may provide similar bio-responses while avoiding enzymatic degradation. In order to perform immobilization of these collagen-like molecules (CLMs) under mild reaction conditions, the bulk materials are first equipped with suitable surface groups using rf plasma methods. Plasma polymer interlayers offer advantages as versatile reactive platforms for the immobilization of proteins and other biologically active molecules. Application of a thin plasma polymer coating from an aldehyde monomer is particularly suitable as it enables direct immobilization of CLMs by reaction with their terminal amine groups, using reductive amination chemistry. An alternative route is via plasma polymer layers that contain carboxylic acid groups and using carbodiimnide chemistry. A third route makes use of alkylamme plasma polymer interlayers, which are less process sensitive than aldehyde and acid plasma coatings. A layer of poly-carboxylic acid compounds such as carboxylic acid terminated PAMAM-starburst dendrimers or carboxymethylated dextran is then attached by carbodiimide chemistry onto the amine plasma layer. Amine-terminated CLMs can then be immobilized onto the poly-carboxylic acid layer. Surface analytical methods have been used to characterize the immobilization steps and to assess the surface coverage. Initial cell attachment and growth assays indicate that the biological performance of the CLMs depends on their amino acid sequence.

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Recent Advances in Effective Reduction of Graphene Oxide for Highly Improved Performance Toward Electrochemical Energy Storage

Energy & Environmental Materials ◽

10.1002/eem2.12001 ◽

2018 ◽

Vol 1 (1) ◽

pp. 5-12 ◽

Cited By ~ 39

Author(s):

Peng Zhang ◽

Zhi Li ◽

Shijie Zhang ◽

Guosheng Shao

Keyword(s):

Graphene Oxide ◽

Energy Storage ◽

Electrochemical Energy Storage ◽

Recent Advances ◽

Effective Reduction ◽

Improved Performance ◽

Electrochemical Energy

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Bilayer graphene oxide membranes for a wearable hemodialyzer

10.1101/2020.05.26.116863 ◽

2020 ◽

Author(s):

Richard P. Rode ◽

Henry H. Chung ◽

Hayley N. Miller ◽

Thomas R. Gaborski ◽

Saeed Moghaddam

Keyword(s):

Graphene Oxide ◽

Cytochrome C ◽

Self Assembly ◽

Bilayer Membrane ◽

Blood Proteins ◽

High Mechanical Strength ◽

Practical Applications ◽

New Process ◽

Improved Performance ◽

Oxide Membranes

2D nanomaterials have long been considered for development of ultra-high throughput membranes, due to their atomically thin nature and high mechanical strength. However, current processes have yet to yield a viable membrane for practical applications due to the lack of scalability and substantially improved performance over existing membranes. Herein, a graphene oxide (GO) bilayer membrane with a permeability of 1562 mL/hr.mmHg.m2, two orders of magnitude higher than existing nanofiltration membranes, and a tight molecular weight cut-off (MWCO) is presented. To build such a membrane, we have developed a new process involving self-assembly and optimization of GO nanoplatelets physicochemical properties. The process produced a highly organized mosaic of nanoplatelets enabling ultra-high permeability and selectivity with only three layers of GO. Performance of the membrane has been evaluated in a simulated hemodialysis application, where it presents a great value proposition. The membrane has a precise molecular cut-off size of 5 nm, adjusted using a molecular interlinker, designed to prevent loss of critical blood proteins. Urea, cytochrome-c, and albumin are used as representative test molecules. Urea and cytochrome-c sieving coefficients of 0.5 and 0.4 were achieved under physiological pressure conditions, while retaining 99% of albumin. Hemolysis, complement activation, and coagulation studies exhibit a performance on par or superior to the existing hemodialyzer materials.

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