Block Copolymer Thermoplastic Elastomers for Microcontact Printing

Abstract

Two commercial thermoplastic block copolymer elastomers with a high stiffness were investigated as stamp materials for microcontact printing and compared to conventional poly(dimethylsiloxane) (PDMS). Stamps with a relief structure were produced by hot embossing techniques, utilizing the thermoplastic properties of these rubberlike block copolymers. It is shown that the stamps based on these copolymers are able to transfer a thiol ink to a gold substrate. After printing, the thiol ink acts as an etch resist, which indicates that a coherent self-assembled monolayer is formed. Like PDMS stamps, specific copolymer stamps can be used for repeated printing without re-inking. Moreover, the higher stiffness of the thermoplastic stamps increases the load above which structural collapse occurs by a factor of 10−15 in comparison to that of identical PDMS stamps, which is potentially useful in the reproduction of structures which are sensitive to sagging, buckling, or pairing. An example is presented of relief structures, which are accurately reproduced with the thermoplastic elastomers, in contrast to identical chemically cross-linked PDMS stamps.

Photoembossing of Periodic Relief Structures Using Polymerization‐ Induced Diffusion: A Combinatorial Study

“…To create these substrates, clean glass plates were coated with a negative photoresist that was subsequently exposed through a stainlesssteel mask with rectangular holes corresponding to the sectors. After development, the substrate was coated with a fluorinated silane ((tridecafluoro-1,1,2,2-tetrahydrooctyl)-1-trichlorosilane) [16]. Finally, the resist was stripped, leaving the sectors hydrophilic while the surrounding area was fluorinated.…”

“…[11][12][13][14][15] Zinc oxide, a semiconductor with a large direct bandgap, possesses unique optical, acoustic, and electronic properties. ZnO is one of the most widely studied metal oxides for use in solar cells, [16] sensors, [17] ultraviolet nanolasers, [18] and bluelight-emitting diodes (LEDs). [19] …”

Sub-Micrometer Patterning Using Soft Lithography

“…For example, block co-polymers (e.g., polystyrene in conjunction with butadiene or ethylene/butylene) seem promising to this end as they can fulfill many of the requirements for high-resolution soft lithography [36,37]. A number of co-polymer formulations are superior to Sylgard 184 in terms of elastic modulus, which makes resultant replicas less susceptible to deformation and distortion.…”

High‐Resolution Contact Printing with Chemically Patterned Flat Stamps Fabricated by Nanoimprint Lithography

“…However, deformation of the soft-polymer stamps due to the limited mechanical stability of the elastomer during stamp fabrication or printing, leading to pairing, buckling, or roof collapse of structures, renders them unsuitable for high-resolution mCP. [5][6][7][8] New stamp materials [9][10][11][12][13] and composite stamps [6,14,15] may overcome these problems. The mechanical issues are a direct consequence of the inclusion of voids as the transport barriers in topographically patterned stamps.…”