Molecular self-assembly (MSA) involves the spontaneous arrangement of molecules without external guidance. This natural process can be witnessed in instances like the formation of lipid bilayer membranes within cells. When intermolecular forces are strategically employed, novel and previously unattainable nanostructures can be created.

In self-assembly, the desired final structure is essentially “encoded” within the characteristics of the molecules being used. Self-assembled monolayers (SAMs) utilize relatively weak intermolecular interactions between specific organic molecules to drive assembly. These interactions include electrostatic forces between oppositely charged polyelectrolytes, as well as affinities between thiols and gold surfaces, or phosphonic acids and oxide surfaces.

Thiols and Gold Surfaces:

The assembly of alkyl thiols on a gold surface is influenced by multiple forces. Apart from the strong sulfur-gold interactions, which facilitate robust bonding of film-forming molecules to the surface, hydrophobic interactions between carbon and hydrogen atoms in alkyl thiol molecules significantly reduce overall surface energy, particularly when the alkyl chain comprises at least ten carbon atoms.

We offer a diverse range of high-purity thiol materials tailored for various self-assembly applications, spanning from soft lithography to chemical and biological sensing. These materials are categorized based on the type of thiol groups:

1. Alkyl thiols (-CH3 terminated)
2. Functionalized thiols
3. Dithiols
4. Ring thiols
5. Protected thiols

Phosphonic Acids and Oxide Surfaces:

Our selection includes phosphate and phosphonate materials designed to expand substrate choices for self-assembled monolayers beyond gold. These polar acidic molecules interact with a variety of metal-oxide surfaces (e.g., Al2O3, Ta2O5, NbO5, ZrO2, and TiO2) and form films with similar ordering as alkyl thiol SAMs on gold.

Nanoimprint Lithography:

Nanoimprint lithography (NIL) is a method for generating micro- and nanostructures in rigid polymers by pressing a solid master with surface-relief features into a thin thermoplastic polymer film, heated to or above its glass transition temperature (Tg). This technique holds promise for producing nanodevices efficiently, without requiring complex tools, and facilitating nanoscale replication for data storage.

We provide an array of nanoimprinting materials, such as poly(methyl methacrylate) (PMMA), along with other thermoplastic and thermosetting polymers (e.g., Polydimethylsiloxane PDMS and polyphthalaldehyde), to optimize the imprinting and subsequent etching steps.

Soft Lithography:

Soft lithography employs micromolding and embossing of flexible elastomers to create or replicate structures. Microcontact printing (mCP) is a part of this technique, involving the transfer of a material monolayer from an elastomeric stamp made of poly(dimethylsiloxane) (PDMS) onto a substrate through conformal contact. Sub-micron surface relief structures can be introduced in PDMS by curing the polymers against a lithographically prepared master. mCP’s advantage lies in its ability to chemically pattern surfaces at the sub-micron level. An elastomeric stamp is coated with small molecules (thiols or silanes) and pressed onto a clean substrate (gold or silicon wafer), transferring a monolayer of material where contact occurs. Another thiol or silane is then applied to fill the background, creating a chemically patterned surface.

We offer a comprehensive selection of silane, thiol, and PDMS materials to facilitate applications that require precise micropatterning and nanopatterning.