| 摘要 |
The invention relates to a method for producing a directed monolayer or multilayer assembly of colloidal nanoparticles attached to an electret substrate, including a step (4) of imparting a surface electric potential to an electret substrate according to a pattern of positive and/or negative electric charges, and a step (6) of contacting an electret substrate with a colloidal dispersion. The colloidal dispersion comprises electrically neutral or near neutral and electrically polarizable colloidal nanoparticles, and a nonpolarizing or weakly polarizing dispersion medium. The absolute value of the surface electric potential and the concentration of polarizable nanoparticles are no lower than a first surface electric potential threshold and no lower than a second concentration threshold, respectively, such as to obtain an assembly having a desired geometric shape, at least the first layer of which is compact in terms of the absence of undesired gaps having sizes greater than the size of two adjacent nanoparticles, preferably not greater than the size of one nanoparticle. |
| 主权项 |
1. A process for the manufacture of a micro/nanostructure formed of colloidal nanoparticles comprising a monolayer or multilayer assembly of colloidal nanoparticles which are attached to an electret substrate, having a freely chosen and predetermined geometric shape, at least the first layer of which is compact in terms of absence of undesired gaps with sizes of greater than or equal to the size of two adjacent nanoparticles, optionally greater than or equal to the size of one nanoparticle, comprising the stages consisting of:
in a first stage, providing an electret substrate, composed of an electret material and having a free receiving surface, then in a second stage, writing a surface electric potential on the receiving surface of the electret substrate according to a predetermined pattern of positive and/or negative electric charges corresponding to the monolayer or multilayer assembly of nanoparticles, then in a third stage, bringing the electret substrate having the receiving surface written with the surface potential according to the desired pattern of electric charges into contact with a colloidal dispersion for a contacting time which is less than or equal to fifteen minutes, wherein: the colloidal dispersion comprises electrically neutral or quasineutral colloidal particles which are electrically polarizable under the action of an external electric field and a dispersing medium, in the form of a liquid solvent or a gas which is substantially devoid of an electrical polarization action, in which the colloidal nanoparticles are dispersed, and the absolute value of the surface electric potential and the concentration of polarizable nanoparticles are respectively greater than or equal to a first surface electric potential threshold and to a second concentration threshold, the first and second thresholds each depending on the nature of the dispersing medium and on the nature of the polarizable nanoparticles, so that after the first contacting time, the micro/nanostructure obtained is a monolayer or multilayer micro/nanostructure having the desired geometric shape, at least the first layer of which is compact in terms of absence of undesired gaps with sizes greater than or equal to the size of two adjacent nanoparticles, optionally greater than or equal to the size of one nanoparticle, the nanoparticles being bonded to one another and/or to the substrate under the action of dielectrophoretic forces created from the interaction between the polarizable nanoparticles and the written surface potential. |
