An Interactive Desktop Computer Program for Simulating Nanometer Scale Surface Pattern Formation

2009 ◽  
Vol 1177 ◽  
Author(s):  
Michael Wang

AbstractNanometer-scale patterns may form as one or more chemical components deposit on a solid substrate. This self-assembly process can be described by a set of nonlinear integral-differential diffusion equations accounting for two opposing factors: phase separation to minimizing Gibb's free energy in individual surface phases and reduction in phase boundaries to minimize surface energy created by phase separation. I here present a desktop computer program that allows us to interactively simulate self-assembly of nanometer-scale surface patterns. In particular, this program provides a convenient tool for studying the effects of temperature variations and preexisting patterns on the self-assembly process. Computer simulations show that an increase in temperature may enlarge pattern sizes and can eventually lead to the disappearance of the patterns.

2001 ◽  
Vol 672 ◽  
Author(s):  
Qin Hu ◽  
Martin Zinke–Allmang ◽  
Ian V. Mitchell

ABSTRACTWe report on the competitive phase separation of copper and tin thin film deposits on a pre–patterned Si(100) surface. The initial pattern on Si(100) was achieved through a thermal decomposition process of an ex–situ grown oxide film. Copper and tin phase separation on silicon is a competitive process with Cu forming preferrably silicide. Sn is observed to cover the silicide clusters when present in a sufficient amount. The pre–patterning of the surface introduces a new length scale in the problem. Our data suggest that this length scale plays a role while the clustering (ripening) length scale is of the same order, i.e., during nucleation and the early phase separation, but that both length scales become independent once the length scale of ripening significantly exceeds the length scale of the surface pattern.


2002 ◽  
Vol 14 (7) ◽  
pp. 3054-3065 ◽  
Author(s):  
Joshua E. Malinsky ◽  
Jonathan G. C. Veinot ◽  
Ghassan E. Jabbour ◽  
Sean E. Shaheen ◽  
Jeffrey D. Anderson ◽  
...  

2013 ◽  
Vol 850-851 ◽  
pp. 92-95
Author(s):  
Yong Wan ◽  
Zhong Yu Cai ◽  
Ming Hui Jia ◽  
Chao Li ◽  
Wan Qin Yang

Silica and polystyrene (PS) microspheres assembled on two quite different patterned silicon substrates, cross-like pillar pattern and eye-like pattern, respectively. The results indicated that the surface pattern imposes a predetermined lattice orientation in colloidal crystals (CCs). Other influent factors, such as microsphere size, the altitude of pattern and the concentration of colloidal suspension, may also play an important role on the self-assembly process.


1999 ◽  
Vol 83 (19) ◽  
pp. 3844-3847 ◽  
Author(s):  
Günter Reiter ◽  
Gilles Castelein ◽  
Pierre Hoerner ◽  
Gérard Riess ◽  
Alexander Blumen ◽  
...  

Author(s):  
Krishna Sailaja A ◽  
Amareshwar P

In order to see the functionality and toxicity of nanoparticles in various food and drug applications, it is important to establish procedures to prepare nanoparticles of a controlled size. Desolvation is a thermodynamically driven self-assembly process for polymeric materials. In this study, we prepared BSA nanoparticles using the desolvation technique using acetone as desolvating agent. Acetone was added intermittently into 1% BSA solution at different pH under stirring at 700 rpm. Amount of acetone added, intermittent timeline of acetone addition, and pH of solution were considered as process parameters to be optimized. The effect of the process parameters on size of the nanoparticles was studied. The results indicated that the size control of BSA nanoparticles was achieved by adding acetone intermittently. The standard deviation of average size of BSA nanoparticles at each preparation condition was minimized by adding acetone intermittently. The intermittent addition in polymeric aqueous solution can be useful for size control for food or drug applications.  


Materials ◽  
2021 ◽  
Vol 14 (15) ◽  
pp. 4239
Author(s):  
Pezhman Mohammadi ◽  
Fabian Zemke ◽  
Wolfgang Wagermaier ◽  
Markus B. Linder

Macromolecular assembly into complex morphologies and architectural shapes is an area of fundamental research and technological innovation. In this work, we investigate the self-assembly process of recombinantly produced protein inspired by spider silk (spidroin). To elucidate the first steps of the assembly process, we examined highly concentrated and viscous pendant droplets of this protein in air. We show how the protein self-assembles and crystallizes at the water–air interface into a relatively thick and highly elastic skin. Using time-resolved in situ synchrotron X-ray scattering measurements during the drying process, we showed that the skin evolved to contain a high β-sheet amount over time. We also found that β-sheet formation strongly depended on protein concentration and relative humidity. These had a strong influence not only on the amount, but also on the ordering of these structures during the β-sheet formation process. We also showed how the skin around pendant droplets can serve as a reservoir for attaining liquid–liquid phase separation and coacervation from the dilute protein solution. Essentially, this study shows a new assembly route which could be optimized for the synthesis of new materials from a dilute protein solution and determine the properties of the final products.


Molecules ◽  
2021 ◽  
Vol 26 (12) ◽  
pp. 3598
Author(s):  
Nirmal K. Shee ◽  
Hee-Joon Kim

A series of porphyrin triads (1–6), based on the reaction of trans-dihydroxo-[5,15-bis(3-pyridyl)-10,20-bis(phenyl)porphyrinato]tin(IV) (SnP) with six different phenoxy Zn(II)-porphyrins (ZnLn), was synthesized. The cooperative metal–ligand coordination of 3-pyridyl nitrogens in the SnP with the phenoxy Zn(II)-porphyrins, followed by the self-assembly process, leads to the formation of nanostructures. The red-shifts and remarkable broadening of the absorption bands in the UV–vis spectra for the triads in CHCl3 indicate that nanoaggregates may be produced in the self-assembly process of these triads. The emission intensities of the triads were also significantly reduced due to the aggregation. Microscopic analyses of the nanostructures of the triads reveal differences due to the different substituents on the axial Zn(II)-porphyrin moieties. All these nanomaterials exhibited efficient photocatalytic performances in the degradation of rhodamine B (RhB) dye under visible light irradiation, and the degradation efficiencies of RhB in aqueous solution were observed to be 72~95% within 4 h. In addition, the efficiency of the catalyst was not impaired, showing excellent recyclability even after being applied for the degradation of RhB in up to five cycles.


Nanomaterials ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 1686
Author(s):  
Ruohong Sui ◽  
Paul A. Charpentier ◽  
Robert A. Marriott

In the past two decades, we have learned a great deal about self-assembly of dendritic metal oxide structures, partially inspired by the nanostructures mimicking the aesthetic hierarchical structures of ferns and corals. The self-assembly process involves either anisotropic polycondensation or molecular recognition mechanisms. The major driving force for research in this field is due to the wide variety of applications in addition to the unique structures and properties of these dendritic nanostructures. Our purpose of this minireview is twofold: (1) to showcase what we have learned so far about how the self-assembly process occurs; and (2) to encourage people to use this type of material for drug delivery, renewable energy conversion and storage, biomaterials, and electronic noses.


Sign in / Sign up

Export Citation Format

Share Document