Perfluorodecyltrichlorosilane, also known as FDTS, is a colorless liquid chemical with molecular formula
C10 H4 Cl3 F17 Si. FDTS molecules form
self-assembled monolayer
Self-assembled monolayers (SAM) of organic molecules are molecular assemblies formed spontaneously on surfaces by adsorption and are organized into more or less large ordered domains. In some cases molecules that form the monolayer do not interact ...
s. They form
covalent
A covalent bond is a chemical bond that involves the sharing of electrons to form electron pairs between atoms. These electron pairs are known as shared pairs or bonding pairs. The stable balance of attractive and repulsive forces between atoms ...
silicon–oxygen bonds to free
hydroxyl
In chemistry, a hydroxy or hydroxyl group is a functional group with the chemical formula and composed of one oxygen atom covalently bonded to one hydrogen atom. In organic chemistry, alcohols and carboxylic acids contain one or more hydroxy ...
(–OH) groups, such as the surfaces of glass, ceramics, or
silica
Silicon dioxide, also known as silica, is an oxide of silicon with the chemical formula , most commonly found in nature as quartz and in various living organisms. In many parts of the world, silica is the major constituent of sand. Silica is one ...
.
Due to its heavily fluorinated tail group, a FDTS monolayer reduces
surface energy
In surface science, surface free energy (also interfacial free energy or surface energy) quantifies the disruption of intermolecular bonds that occurs when a surface is created. In solid-state physics, surfaces must be intrinsically less energe ...
. Deposition of a FDTS monolayer is achieved by a relatively simple process, also known as
molecular vapor deposition
Molecular vapor deposition is the gas-phase reaction between surface reactive chemicals and an appropriately receptive surface. Often bi-functional silanes are used in which one termination of the molecule is reactive. For example, a functional ...
(MVD) It usually deposits from a vapor phase, at room to near-to-room temperatures (50 °C) and is thus compatible with most substrates. The process is usually carried out in a vacuum chamber and assisted by the presence of
water
Water (chemical formula ) is an inorganic, transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's hydrosphere and the fluids of all known living organisms (in which it acts as a ...
vapor. Treated surfaces have water repellent and
friction
Friction is the force resisting the relative motion of solid surfaces, fluid layers, and material elements sliding against each other. There are several types of friction:
*Dry friction is a force that opposes the relative lateral motion of t ...
reducing properties.
For this reason, a FDTS monolayer is often applied to movable microparts of
microelectromechanical systems
Microelectromechanical systems (MEMS), also written as micro-electro-mechanical systems (or microelectronic and microelectromechanical systems) and the related micromechatronics and microsystems constitute the technology of microscopic devices, ...
(
MEMS
Microelectromechanical systems (MEMS), also written as micro-electro-mechanical systems (or microelectronic and microelectromechanical systems) and the related micromechatronics and microsystems constitute the technology of microscopic devices, ...
). A FDTS monolayer reduces surface energy and prevents sticking, so they are used to coat micro- and nano-features on stamps for a
nanoimprint lithography
Nanoimprint lithography (NIL) is a method of fabricating nanometer scale patterns. It is a simple nanolithography process with low cost, high throughput and high resolution. It creates patterns by mechanical deformation of imprint resist and subse ...
which is becoming a method of choice for making electronics,
organic photodiodes, microfluidics and other.
Reduced surface energy is helpful for reduction of ejection force and demolding of polymer parts in an
injection molding
Injection moulding (U.S. spelling: injection molding) is a manufacturing process for producing parts by injecting molten material into a mould, or mold. Injection moulding can be performed with a host of materials mainly including metals (for ...
and FDTS coating was applied
onto some metallic
injection molding
Injection moulding (U.S. spelling: injection molding) is a manufacturing process for producing parts by injecting molten material into a mould, or mold. Injection moulding can be performed with a host of materials mainly including metals (for ...
molds and inserts.
References
* Srinivasan, U.; Houston, M.R.; Howe, R.T.; Maboudian, R.; , "Alkyltrichlorosilane-based self-assembled monolayer films for stiction reduction in silicon micromachines," Microelectromechanical Systems, Journal of , vol.7, no.2, pp. 252–260, Jun 1998. doi: 10.1109/84.679393
* Ruben B. A. Sharpe, Dirk Burdinski, Jurriaan Huskens, Harold J. W. Zandvliet, David N. Reinhoudt, and Bene Poelsema, Chemically Patterned Flat Stamps for Microcontact Printing, Journal of the American Chemical Society 2005 127 (29), 10344-10349.
* Ashurst, W. R., Carraro, C., and Maboudian, R., “Vapor Phase Anti-Stiction Coatings for MEMS,” IEEE Transactions on Device and Materials Reliability, Vol. 3, No. 4, pp. 173–178, 2003. doi: 10.1109/TDMR.2003.821540
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Organofluorides
Thin films
Organosilicon compounds