scholarly journals Multiscale additive manufacturing of polymers using 3D photo-printable self-assembling ionic liquid monomers

2019 ◽  
Vol 4 (3) ◽  
pp. 580-585 ◽  
Author(s):  
Bineh G. Ndefru ◽  
Bryan S. Ringstrand ◽  
Sokhna I.-Y. Diouf ◽  
Sönke Seifert ◽  
Juan H. Leal ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Additive Manufacturing ◽  
Self Assembly ◽  
Low Cost ◽  
Low Resolution ◽  
Top Down ◽  
Bottom Up ◽  
Cost Approach ◽  
Self Assembling ◽  
Nanoscale Features

Combining bottom-up self-assembly with top-down 3D photoprinting affords a low cost approach for the introduction of nanoscale features into a build with low resolution features.

Block Copolymer Films Hierarchical Assembly in Confinement

2007 ◽  
Vol 364-366 ◽  
pp. 437-441
Author(s):  
Yong Zhi Cao ◽  
Shen Dong ◽  
Ying Chun Liang ◽  
Tao Sun ◽  
Yong Da Yan
Keyword(s):  
Block Copolymer ◽  
Self Assembly ◽  
Structural Control ◽  
Computer Control ◽  
The Self ◽  
Top Down ◽  
Bottom Up ◽  
Dimensional Precision ◽  
Periodic Arrays ◽  
Copolymer Films

Ultrathin block copolymer films are promising candidates for bottom-up nanotemplates in hybrid organic-inorganic electronic, optical, and magnetic devices. Key to many future applications is the long range ordering and precise placement of the phase-separated nanoscale domains. In this paper, a combined top-down/bottom-up hierarchical approach is presented on how to fabricate massive arrays of aligned nanoscale domains by means of the self-assembly of asymmetric poly (styrene-block-ethylene/butylenes-block-styrene) (SEBS) tirblock copolymers in confinement. The periodic arrays of the poly domains were orientated via the introduction of AFM micromachining technique as a tool for locally controlling the self-assembly process of triblock copolymers by the topography of the silicon nitride substrate. Using the controlled movement of 2- dimensional precision stage and the micro pressure force between the tip and the surface by computer control system, an artificial topographic pattern on the substrate can be fabricated precisely. Coupled with solvent annealing technique to direct the assembly of block copolymer, this method provides new routes for fabricating ordered nanostructure. This graphoepitaxial methodology can be exploited in hybrid hard/soft condensed matter systems for a variety of applications. Moreover, Pairing top-down and bottom-up techniques is a promising, and perhaps necessary, bridge between the parallel self-assembly of molecules and the structural control of current technology.

scholarly journals Middle-Out Approaches to Reform of University Teaching and Learning: Champions striding between the top-down and bottom-up approaches

2005 ◽  
Vol 6 (1) ◽  
Author(s):  
Rick Cummings ◽  
Rob Phillips ◽  
Rhondda Tilbrook ◽  
Kate Lowe
Keyword(s):  
Change Management ◽  
Teaching And Learning ◽  
Low Cost ◽  
Theory And Practice ◽  
University Teaching ◽  
Top Down ◽  
Bottom Up ◽  
Executive Staff ◽  
Accepted Practice ◽  
External Forces

<P>In recent years, Australian universities have been driven by a diversity of external forces, including funding cuts, massification of higher education, and changing student demographics, to reform their relationship with students and improve teaching and learning, particularly for those studying off-campus or part-time. Many universities have responded to these forces either through formal strategic plans developed top-down by executive staff or through organic developments arising from staff in a bottom-up approach. By contrast, much of Murdoch University's response has been led by a small number of staff who have middle management responsibilities and who have championed the reform of key university functions, largely in spite of current policy or accepted practice. This paper argues that the "middle-out" strategy has both a basis in change management theory and practice, and a number of strengths, including low risk, low cost, and high sustainability. Three linked examples of middle-out change management in teaching and learning at Murdoch University are described and the outcomes analyzed to demonstrate the benefits and pitfalls of this approach.</P>

Mapping seabed assemblages using comparative top-down and bottom-up classification approaches

2006 ◽  
Vol 63 (7) ◽  
pp. 1536-1548 ◽  
Author(s):  
Paul D Eastwood ◽  
Sami Souissi ◽  
Stuart I Rogers ◽  
Roger A Coggan ◽  
Craig J Brown
Keyword(s):  
Low Cost ◽  
A Priori ◽  
Ground Truth ◽  
Unsupervised Classification ◽  
Physical Structure ◽  
Unconsolidated Sediments ◽  
Top Down ◽  
Bottom Up ◽  
Infaunal Community ◽  
Acoustic Technologies

Acoustic technologies yield many benefits for mapping the physical structure of seabed environments but are not ideally suited to classifying associated biological assemblages. We tested this assumption using benthic infauna data collected off the south coast of England by applying top-down (supervised) and bottom-up (unsupervised) classification approaches. The top-down approach was based on an a priori acoustic classification of the seabed followed by characterization of the acoustic regions using ground-truth biological samples. By contrast, measures of similarity between the ground-truth infaunal community data formed the basis of the bottom-up approach to assemblage classification. For both approaches, individual assemblages were mapped by first computing Bayesian conditional probabilities for ground-truth stations to estimate the probability of each station belonging to an assemblage. Assemblage distributions were then interpolated over a regular grid and characterized using an indicator value index. While the two methods of classification yielded assemblages and output maps that were broadly comparable, the bottom-up approach arrived at a slightly better defined set of biological assemblages. This suggests that acoustically derived seabed data are not ideally suited to class ifying biological assemblages over unconsolidated sediments, despite offering considerable advantages in providing rapid and low-cost assessments of seabed physical structure.

PEPTIDE NANOFILAMENTS USED FOR REPLICA-MOLDING: A COMBINATION OF "BOTTOM-UP" AND "TOP-DOWN"

2007 ◽  
Vol 14 (02) ◽  
pp. 301-307 ◽  
Author(s):  
YUZHAO TANG ◽  
XIAODONG ZHANG ◽  
JIELIN SUN ◽  
JUN HU ◽  
FENG ZHANG ◽  
...  
Keyword(s):  
Nanometer Scale ◽  
Top Down ◽  
Bottom Up ◽  
Polymeric Surfaces ◽  
Replica Molding ◽  
Force Microscopy ◽  
Self Assembling ◽  
Atomic Force ◽  
New Applications

A novel nanofabrication method that combines both "bottom-up" (template-assisted peptide self-assembling) and "top-down" (replica molding) techniques is introduced. A designer peptide, GAV-9 (NH2-VGGAVVAGV-CONH2), can epitaxially self-assemble into nanofilaments on the surface of mica, which is further used as the diversified masters for the application of replica molding. With in situ atomic force microscopy monitoring, several typical masters are fabricated by peptide self-assembling on the surface of mica. These masters can be easily molded into hard poly(dimethylsiloxane) surfaces, and then further replica-molded into polyurethane surfaces. The polymeric surfaces with regular 1D and 2D patterns on the nanometer scale are expected to have new applications in nanostructure's fabrication.

Block Copolymer Lithography: Merging “Bottom-Up” with “Top-Down” Processes

MRS Bulletin ◽  
2005 ◽  
Vol 30 (12) ◽  
pp. 952-966 ◽  
Author(s):  
Craig J. Hawker ◽  
Thomas P. Russell
Keyword(s):  
Self Assembly ◽  
Polymer Chains ◽  
Top Down ◽  
Bottom Up ◽  
Robust Solution ◽  
Size Scale ◽  
Design And Synthesis ◽  
Manufacturing Techniques ◽  
Future Demands ◽  
Alternative Routes

AbstractAs the size scale of device features becomes ever smaller, conventional lithographic processes become increasingly more difficult and expensive, especially at a minimum feature size of less than 45 nm. Consequently, to achieve higher-density circuits, storage devices, or displays, it is evident that alternative routes need to be developed to circumvent both cost and manufacturing issues.An ideal process would be compatible with existing technological processes and manufacturing techniques; these strategies, together with novel materials, could allow significant advances to be made in meeting both short-term and long-term demands for higher-density, faster devices. The self-assembly of block copolymers (BCPs), two polymer chains covalently linked together at one end, provides a robust solution to these challenges. As thin films, immiscible BCPs self-assemble into a range of highly ordered morphologies where the size scale of the features is only limited by the size of the polymer chains and are, therefore, nanoscopic.While self-assembly alone is sufficient for a number of applications in fabricating advanced microelectronics, directed, self-orienting, self-assembly processes are also required to produce complex devices with the required density and addressability of elements to meet future demands. Both strategies require the design and synthesis of polymers that have well-defined characteristics such that the necessary fine control over the morphology, interfacial properties, and simplicity of processes can be realized. By combining tailored self-assembly processes (a “bottom-up” approach) with microfabrication processes (a “top-down” approach), the ever-present thirst of the consumer for faster, better, and cheaper devices can be met in very simple, yet robust, ways. The integration of novel chemistries with the manipulation of self-assembly will be treated in this article.

scholarly journals Engineered Microgels—Their Manufacturing and Biomedical Applications

Micromachines ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 45
Author(s):  
Hamzah Alzanbaki ◽  
Manola Moretti ◽  
Charlotte A. E. Hauser
Keyword(s):  
Biomedical Applications ◽  
Attractive Alternative ◽  
Top Down ◽  
Bottom Up ◽  
Advantages And Disadvantages ◽  
Hydrogel Particles ◽  
Self Assembling ◽  
Synthetic Materials ◽  
Micrometer Scale ◽  
Cell Carriers

Microgels are hydrogel particles with diameters in the micrometer scale that can be fabricated in different shapes and sizes. Microgels are increasingly used for biomedical applications and for biofabrication due to their interesting features, such as injectability, modularity, porosity and tunability in respect to size, shape and mechanical properties. Fabrication methods of microgels are divided into two categories, following a top-down or bottom-up approach. Each approach has its own advantages and disadvantages and requires certain sets of materials and equipments. In this review, we discuss fabrication methods of both top-down and bottom-up approaches and point to their advantages as well as their limitations, with more focus on the bottom-up approaches. In addition, the use of microgels for a variety of biomedical applications will be discussed, including microgels for the delivery of therapeutic agents and microgels as cell carriers for the fabrication of 3D bioprinted cell-laden constructs. Microgels made from well-defined synthetic materials with a focus on rationally designed ultrashort peptides are also discussed, because they have been demonstrated to serve as an attractive alternative to much less defined naturally derived materials. Here, we will emphasize the potential and properties of ultrashort self-assembling peptides related to microgels.

scholarly journals New ternary water-soluble support from self-assembly of β-cyclodextrin-ionic liquid and an anionic polymer for a dialysis device

2021 ◽  
Author(s):  
Asmaa Bouyahya ◽  
Berthe-Sandra Sembo-Backonly ◽  
Audrey Favrelle-Huret ◽  
Sébastien Balieu ◽  
Frédéric Guillen ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Self Assembly ◽  
Electrostatic Interactions ◽  
Low Cost ◽  
Water Soluble ◽  
Anionic Polymer ◽  
Imidazolium Cation ◽  
Water Soluble Polymer ◽  
Styrene Sulfonate ◽  
Poly Styrene Sulfonate

Abstract We developed a new hybrid material resulting from an innovative supramolecular tripartite association between an ionic liquid covalently immobilized on primary β-cyclodextrins rim and an anionic water-soluble polymer. Two hydrophilic ternary complexes based on native and permethylated β-cyclodextrins substituted with an ionic liquid and immobilized on poly(styrene sulfonate) (CD-IL+PSS− and CD(OMe)IL+PSS−) were obtained by simple dialysis with a cyclodextrin maximal grafting rate of 25% and 20% on the polymer, respectively. These polyelectrolytes are based on electrostatic interactions between the opposite charges of the imidazolium cation of the ionic liquid and the poly(styrene sulfonate) anion. The inclusion properties of the free cavities of the cyclodextrins and the synergic effect of the polymeric matrix were studied with three reference guests such as phenolphthalein, p-nitrophenol, and 2-anilinonaphthalene-6-sulfonic acid using UV-visible, fluorescent, and NMR spectroscopies. The support has been applied successfully in dialysis device to extract and concentrated aromatic model molecule. This simple and flexible synthetic strategy opens the way to new hybrid materials useful for fast and low-cost ecofriendly extraction techniques relevant for green analytical chemistry.

A New Process to Fabricate Three Dimensional Ordered Nano Dot Array Structures by Nano Plastic Forming and Dewetting

2012 ◽  
Vol 523-524 ◽  
pp. 627-632
Author(s):  
Zhen Xing Li ◽  
Akinori Yamanaka ◽  
Masahiko Yoshino
Keyword(s):  
Metal Layer ◽  
Low Cost ◽  
Three Dimensional ◽  
Process Conditions ◽  
Top Down ◽  
Bottom Up ◽  
Spacer Layer ◽  
New Process ◽  
Plastic Forming ◽  
Array Structures

Three dimensional (3D) nano/quantum dot array structures have attracted more and more attention due to their broad applications. A new fabrication method of multilayer ordered nano dot array with low cost and high throughput is developed in this paper. This process is combination of Top-down and Bottom-up approaches: Nano Plastic Forming (NPF) patterning of metal layer coated on the substrate as Top-down approach and self-organization by dewetting as Bottom-up approach. Effects of process conditions on 3D nano-dot array formation are studied experimentally. Regularity and uniformity of first layer nano-dot array is transferred to the second layer nano-dots by optimizing thickness of the spacer layer and Au coating layer. Multilayer ordered nano dot array structures with good alignment are obtained by repeating coating and annealing processes.

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