Chapter 7
Reactive µCP on Ultrathin Block
Copolymer Films: Investigation
of the µCP Mechanism and Applications
to Sub-µm (Bio)Molecular Patterning
In this chapter, three different, complementary lithographic approaches to produce
chemical patterns on ultrathin polystyrene-b-poly(t-butyl acrylate) (PS 690 -bPtBA 1210 ) films are introduced, which can be expanded to obtain patterns of
biomolecules with (sub)micrometer feature sizes. In this chapter, three different,
complementary lithographic approaches to produce chemical patterns on ultrathin
polystyrene-b-poly(t-butyl acrylate) (PS 690 -b-PtBA 1210 ) films are introduced, which
can be expanded to obtain patterns of biomolecules with (sub)micrometer feature
sizes. In approach (A), PS 690 -b-PtBA 1210 films were homogeneously hydrolyzed
and subsequently functionalized with (N-hydroxysuccinimide) (NHS). Two types
of molecules, fluoresceinamine and BSA, were patterned and covalently bound on
the activated polymer films in sequential direct molecular transfer steps using reactive μCP. NHS functionalized polymer films were also patterned with PEG 500 NH 2
by reactive μCP in approach (B). The PEG layer was used as antifouling layer to
prevent the non-specific adsorption of (bio)molecules in the subsequent covalent
coupling step of fluoresceinamine and bovine serum albumin (BSA) carried out
in solution. The area selective immobilization was also successfully demonstrated
for 25mer probe DNA, as shown by the fluorescence microscopic detection of the
hybridization of dye-labeled target DNA. In approach (C), the polymer films were
locally hydrolyzed with trifluoroacetic acid that was locally applied on the films
using acid-soaked poly(dimethyl siloxane) (PDMS) stamps. A detailed study of the
reactive μCP mechanism led to the conclusion that ink spreading and diffusion must
be controlled for faithful pattern transfer, in particular on the sub-micrometer level.
In addition, it was found that patterns with micrometer scale dimensions could be
fabricated by using stamps with >10 μm dimensions by controlling the spreading of
trifluoroacetic acid. Thus, ultrahigh density patterns can be conveniently fabricated.
© Shanghai Jiao Tong University Press 2021
C. Feng et al., Microfabrication of Stimuli-Responsive Polymers,
https://doi.org/10.1007/978-981-33-6869-9_7
125
Reactive µCP on Ultrathin Block
Copolymer Films: Investigation
of the µCP Mechanism and Applications
to Sub-µm (Bio)Molecular Patterning
In this chapter, three different, complementary lithographic approaches to produce
chemical patterns on ultrathin polystyrene-b-poly(t-butyl acrylate) (PS 690 -bPtBA 1210 ) films are introduced, which can be expanded to obtain patterns of
biomolecules with (sub)micrometer feature sizes. In this chapter, three different,
complementary lithographic approaches to produce chemical patterns on ultrathin
polystyrene-b-poly(t-butyl acrylate) (PS 690 -b-PtBA 1210 ) films are introduced, which
can be expanded to obtain patterns of biomolecules with (sub)micrometer feature
sizes. In approach (A), PS 690 -b-PtBA 1210 films were homogeneously hydrolyzed
and subsequently functionalized with (N-hydroxysuccinimide) (NHS). Two types
of molecules, fluoresceinamine and BSA, were patterned and covalently bound on
the activated polymer films in sequential direct molecular transfer steps using reactive μCP. NHS functionalized polymer films were also patterned with PEG 500 NH 2
by reactive μCP in approach (B). The PEG layer was used as antifouling layer to
prevent the non-specific adsorption of (bio)molecules in the subsequent covalent
coupling step of fluoresceinamine and bovine serum albumin (BSA) carried out
in solution. The area selective immobilization was also successfully demonstrated
for 25mer probe DNA, as shown by the fluorescence microscopic detection of the
hybridization of dye-labeled target DNA. In approach (C), the polymer films were
locally hydrolyzed with trifluoroacetic acid that was locally applied on the films
using acid-soaked poly(dimethyl siloxane) (PDMS) stamps. A detailed study of the
reactive μCP mechanism led to the conclusion that ink spreading and diffusion must
be controlled for faithful pattern transfer, in particular on the sub-micrometer level.
In addition, it was found that patterns with micrometer scale dimensions could be
fabricated by using stamps with >10 μm dimensions by controlling the spreading of
trifluoroacetic acid. Thus, ultrahigh density patterns can be conveniently fabricated.
© Shanghai Jiao Tong University Press 2021
C. Feng et al., Microfabrication of Stimuli-Responsive Polymers,
https://doi.org/10.1007/978-981-33-6869-9_7
125