Geometrical confinement

Crocker J C and Grier D G 1996 When like charges attract the effects of geometrical confinement on long-range colloidal interactions Phys. Rev. Lett. 77 1897-900... 

For ultrathin films, it should also be mentioned that Tg is strongly subjected to interface effects, thus it may be higher or lower than in the bulk material [3], This finding can be attributed to the interplay between surface and geometric confinement effects. Due to attractive interactions at interfaces, the molecular dynamics may be slowed down, resulting in an increase of Tg, whereas the confinement to a small layer may lead to an increase in the free volume, resulting in a decrease of Tg [4],... 

When molecules adsorb to a flat substrate, their conformation is modified due to the geometric confinement between the two interfaces and the direct interaction to the substrate. This state can be far from equilibrium if the adsorption process has been fast and irreversible. In this case, the molecules do not have time to sample the whole assembly of thermodynamic states and get trapped kinetically at contact sites. The reversibility is difficult to achieve because of the great size of the molecules and strong adhesion which might exceeds kBT by far. In order to approach an equilibrium state, the sample has to be pre-... 

This relation was confirmed by Kholodenko (1996) who started from detailed picture of geometrically confined polymer chain and used more sophisticated methods of calculation. 

Zhang J, Jonas J. NMR Study of the geometric confinement effects of the anisotropic rotational diffusion of acetonitrile-dj. J Phys Chem 1993 97 8812-8815. 

The profoundly different optical interactions in subwavelength dielectric wires noted in the introduction lead to considerable differences in Raman scattering intensities from bulk crystal samples as well as strong polarization dependencies. Such phenomena arise from the effects of geometric confinement on light scattering due to the boundary mismatch of the dielectric function at optical frequencies. 

The structural and dynamic properties of water may be affected by both purely geometrical confinement and/or interaction forces at the interface. Therefore, a detailed description of these properties must take into account the nature of the substrate and its affinity to form bonds with water molecules, as well as the hydration level or number of water layers. In order to discriminate between these effects, reliable model systems exhibiting hydrophilic or hydrophobic interactions with water are required. This appears to be the appropriate strategy to permit some understanding of the behavior of water close to a biological macromolecule, as presented in the following. 

This review focuses on two different types of polyelectrolyte membrane. The first part deals with thin free-standing liquid films formed from aqueous polyelectrolyte/surfactant solutions. Free-standing films are interesting in two respects. First, the film can be considered as the building block of a foam so that its properties affect the behavior of the whole macroscopic foam. In this context it is the molecular structure at and near the film surfaces rather than the structure of the film core which is important. Second, the free-standing film presents a slit pore which enables study of the effect of geometrical confinement on the structuring of polymers. The liquid free-... 

Richer , R., Geometrical confinement and cooperativity in supercooled liquids studied by solvation dynamics. Phys. Rev. B 54, 762 (1996). 

Anderson et al. (1996) used Eq. [14], in conjunction with digitized images of thin sections, to investigate the influence of pore space geometry on diffusion in soil systems. Giona et al. (1996) applied renormalization analysis to study diffusion and convection on fractal media. Coppens (1997), Santra et al. (1997), and Levitz (1998) have studied the effects of geometrical confinement on diffusion in the Knudsen regime, in which particle collisions with a fractal internal surface dominate over particle-particle collisions. 

Levitz, P. 1998. Off-lattice reconstruction of porous media critical evaluation, geometrical confinement and molecular transport. Adv, Colloid Interface Sci. 77 71-106. 

While the electronic and optical properties of semiconductor NCs are well luiderstood, the vibrational properties (phonons confined in spherical quantum dots of several nanometers in size) of NCs received much less attention until the last few years [1-4]. An accurate description of the vibrational modes of a NC is of fundamental interest and is required to understand the coupling of vibrational modes to electronic charge. Recently, it has been shown theoretically that geometrical confinement becomes important both for infrared and Raman-active phonons in the limit of a small size of QDs [5]. In this paper, we report the observation of coupled phonon modes in ZnSe spherical quantum dots. 

Considering a free diatomic molecule, thermal fluctuations result in either extension or compression of the bond, depending on the packing density and geometric confinement. Weiner et al. have shown that the time-average bond force has two... 

Bon and Kumacheva and coworkers [104] demonstrated that monodisperse solids-stabilized droplets could be generated in a microfluidic flow focusing device, whereby the solid particles were initially present in the dispersed phase. Polymerization of the monomer droplets led to hybrid polymer microspheres. They also showed that non-spherical particles could be obtained by geometric confinement of the droplets in the channel [104,105]. 

---