Self-Assembly of Mesoscopic Metal-Polymer Amphiphiles

Science ◽  
2004 ◽  
Vol 303 (5656) ◽  
pp. 348-351 ◽  
Author(s):  
S. Park
Keyword(s):  
2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Meneka Banik ◽  
Shaili Sett ◽  
Chirodeep Bakli ◽  
Arup Kumar Raychaudhuri ◽  
Suman Chakraborty ◽  
...  

AbstractSelf-assembly of Janus particles with spatial inhomogeneous properties is of fundamental importance in diverse areas of sciences and has been extensively observed as a favorably functionalized fluidic interface or in a dilute solution. Interestingly, the unique and non-trivial role of surface wettability on oriented self-assembly of Janus particles has remained largely unexplored. Here, the exclusive role of substrate wettability in directing the orientation of amphiphilic metal-polymer Bifacial spherical Janus particles, obtained by topo-selective metal deposition on colloidal Polymestyere (PS) particles, is explored by drop casting a dilute dispersion of the Janus colloids. While all particles orient with their polymeric (hydrophobic) and metallic (hydrophilic) sides facing upwards on hydrophilic and hydrophobic substrates respectively, they exhibit random orientation on a neutral substrate. The substrate wettability guided orientation of the Janus particles is captured using molecular dynamic simulation, which highlights that the arrangement of water molecules and their local densities near the substrate guide the specific orientation. Finally, it is shown that by spin coating it becomes possible to create a hexagonal close-packed array of the Janus colloids with specific orientation on differential wettability substrates. The results reported here open up new possibilities of substrate-wettability driven functional coatings of Janus particles, which has hitherto remained unexplored.


2007 ◽  
Vol 6 (8) ◽  
pp. 609-614 ◽  
Author(s):  
Zhihong Nie ◽  
Daniele Fava ◽  
Eugenia Kumacheva ◽  
Shan Zou ◽  
Gilbert C. Walker ◽  
...  

Coatings ◽  
2021 ◽  
Vol 11 (10) ◽  
pp. 1171
Author(s):  
Irina Boginskaya ◽  
Aliia Gainutdinova ◽  
Alexey Gusev ◽  
Karen Mailyan ◽  
Anton Mikhailitsyn ◽  
...  

Substrates based on the metal-polymer nanocomposites 2,3-dichloro-p-xylylene-silver (PCPX-Ag) that realize the effect of surface-enhanced Raman scattering (SERS) were developed. To obtain nanocomposites, the vapor-phase polymerization method was used (VDP), which makes it possible to control the nanocomposite microstructure. In the process of self-assembly during VDP, nanocomposite films with inclusions of silver particles were formed on the polycore substrates. Silver content varied from 2.5 to 16% vol. The possibility of using such substrates for the detection of low-molecular substances, for example 5,5′-dithiobis- (2-nitrobenzoic acid) (DTNB) analyte, by the SERS method with an enhancement factor of up to 104, was demonstrated. The dependence of the SERS spectra enhancement on the microstructure of the nanocomposite and the silver content was determined. The optical and morphological properties of nanocomposites were also investigated and their dependence on the silver content was shown. It has been demonstrated that the nanocomposite is SERS selective since when working with complex solutions in the presence of high molecular weight substances, signal enhancement was only observed for low molecular weight substances.


2002 ◽  
Vol 739 ◽  
Author(s):  
M. Zubris ◽  
M. Solimando ◽  
E. P. Goldberg ◽  
S. Reich ◽  
R. Tannenbaum

ABSTRACTThe selective interaction of metal clusters with various polymers constitutes the basis for the self-assembly approach to the synthesis of organic-inorganic hybrid materials, that leads to the control of particle size, geometry and dispersion gradient. Metal particles were synthesized by the thermal decomposition of an organometallic precursor, in this case, iron pentacarbonyl, in the presence of a polymer matrix. Under the conditions utilized for these reactions, the aggregation of the metallic clusters competed with the interactions between the growing metal fragments and the polymer matrix. The dominance of one reaction route as compared to the other, ultimately determined the equilibrium particle shape, size and distribution for each metal-polymer system. In this work, we attempted to analyze the formation of iron oxide nanoclusters in several structurally-distinct polymers, and developed a general mechanistic view to explain the characteristics of the polymer-metal oxide hybrid materials that were obtained.


Author(s):  
D. Reis ◽  
B. Vian ◽  
J. C. Roland

Wall morphogenesis in higher plants is a problem still open to controversy. Until now the possibility of a transmembrane control and the involvement of microtubules were mostly envisaged. Self-assembly processes have been observed in the case of walls of Chlamydomonas and bacteria. Spontaneous gelling interactions between xanthan and galactomannan from Ceratonia have been analyzed very recently. The present work provides indications that some processes of spontaneous aggregation could occur in higher plants during the formation and expansion of cell wall.Observations were performed on hypocotyl of mung bean (Phaseolus aureus) for which growth characteristics and wall composition have been previously defined.In situ, the walls of actively growing cells (primary walls) show an ordered three-dimensional organization (fig. 1). The wall is typically polylamellate with multifibrillar layers alternately transverse and longitudinal. Between these layers intermediate strata exist in which the orientation of microfibrils progressively rotates. Thus a progressive change in the morphogenetic activity occurs.


Author(s):  
M. Kessel ◽  
R. MacColl

The major protein of the blue-green algae is the biliprotein, C-phycocyanin (Amax = 620 nm), which is presumed to exist in the cell in the form of distinct aggregates called phycobilisomes. The self-assembly of C-phycocyanin from monomer to hexamer has been extensively studied, but the proposed next step in the assembly of a phycobilisome, the formation of 19s subunits, is completely unknown. We have used electron microscopy and analytical ultracentrifugation in combination with a method for rapid and gentle extraction of phycocyanin to study its subunit structure and assembly.To establish the existence of phycobilisomes, cells of P. boryanum in the log phase of growth, growing at a light intensity of 200 foot candles, were fixed in 2% glutaraldehyde in 0.1M cacodylate buffer, pH 7.0, for 3 hours at 4°C. The cells were post-fixed in 1% OsO4 in the same buffer overnight. Material was stained for 1 hour in uranyl acetate (1%), dehydrated and embedded in araldite and examined in thin sections.


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