Forming patterns using crosslinkable reactive polymers
Various patterning methods utilize certain crosslinkable reactive polymers comprise -A- and -B- recurring units, arranged randomly along a backbone. The -A- recurring units comprise pendant aromatic sulfonic acid oxime ester groups that are capable of providing pendant aromatic sulfonic acid groups upon irradiation with radiation having a λ max of at least 150 nm and up to and including 450 nm. The -A- recurring units are present in the reactive polymer in an amount of up to and including 98 mol % based on total reactive polymer recurring units. The -B- recurring units comprise pendant groups that provide crosslinking upon generation of the aromatic sulfonic acid groups in the -A- recurring units. The -B- recurring units are present in an amount of at least 2 mol %, based on total reactive polymer recurring units.
1. A method comprising:
providing a polymeric layer comprising a copolymer that comprises a backbone of at least -A- and -B- recurring units, all recurring units being arranged randomly along the backbone, wherein
the -A- recurring units comprise pendant groups that are capable of providing pendant aromatic sulfonic acid groups upon irradiation with radiation having a λ max of at least 150 nm and up to and including 450 nm, the -A- recurring units being present in the copolymer in an amount of up to and including 98 mol % based on total copolymer recurring units, and
the -B- recurring units comprise pendant groups that can provide crosslinking upon generation of the aromatic sulfonic acid groups in the -A- recurring units, the -B- recurring units being present in the copolymer in an amount of at least 2 mol %, based on total copolymer recurring units,
patternwise exposing the polymeric layer to radiation having a λ max of at least 150 nm and up to and including 450 nm to provide pendant sulfonic acid groups in the copolymer and to provide crosslinking in the copolymer in the exposed regions of the polymeric layer,
neutralizing the pendant sulfonic acid groups in the exposed regions of the polymeric layer to provide pendant neutralized sulfonic acid groups,
contacting both the exposed and non-exposed regions of the polymeric layer with a polycationic colorant that ionically binds to at least some of the pendant neutralized sulfonic acid groups in the exposed regions of the polymeric layer, and that adsorbs to the polymeric layer in the non-exposed regions, and
washing the polymeric layer with an aqueous solution to remove non-bound polycationic colorant from the exposed regions of the polymeric layer and non-adsorbed polycationic colorant from the non-exposed regions of the polymeric layer.
2. The method of claim 1 , further comprising, after washing the polymeric layer:
contacting the polymeric layer with positively-charged colloidal particles that adhere to the exposed regions of the polymeric layer having adsorbed polycationic colorant, and
again washing the polymeric layer to remove non-adhering positively-charged colloidal particles from the non-exposed regions of the polymeric layer.
3. The method of claim 2 , wherein the again washing is carried out at a pressure of at least 5 psi and up to and including 20 psi.
4. The method of claim 2 , wherein the positively-charged colloidal particles have an average diameter of at least 0.2 μm and up to and including 8 μm.
5. The method of claim 2 , wherein the positively-charged colloidal particles are metal ions.
6. The method of claim 5 , wherein the positively-charged colloidal particles are silver ions, copper ions, platinum ions, nickel ions, palladium ions, iron ions, iridium ions, rhodium ions, or tin ions.
7. The method of claim 2 , wherein the positively-charged colloidal particles are non-metallic organic polymeric particles having positively-charged surface groups, or inorganic particles having positively-charged surface groups.
8. The method of claim 1 , further comprising after washing the polymeric layer:
contacting the polymeric layer with negatively-charged colloidal particles that adhere to the non-exposed regions of the polymeric layer, and
again washing the polymeric layer to remove non-adhering negatively-charged colloidal particles from the exposed regions of the polymeric layer.
9. The method of claim 8 , wherein the negatively-charged colloidal particles have an average diameter of at least 0.2 μm and up to and including 8 μm.
10. The method of claim 8 , wherein the negatively-charged colloidal particles are negatively-charged silica particles or organic polymeric particles having negatively-charged surface groups.
11. The method of claim 1 , wherein the copolymer comprises -A- recurring units that are present in an amount of at least 50 mol % and up to and including 98 mol % based on total copolymer recurring units, and -B-recurring units that are present in an amount of at least 2 mol % and up to and including 50 mol % based on total copolymer recurring units.
12. The method of claim 1 , wherein the -B- recurring units comprise pendant crosslinkable epoxy groups.
13. The method of claim 1 , wherein the copolymer further comprises one or more additional recurring units that are different from all -A- and -B- recurring units in an amount of at least 3 mol % and up to and including 25 mol % based on the total copolymer recurring units.
14. The method of claim 1 , wherein upon irradiation, the reactive polymer is capable of having an ion exchange capacity of at least 20% based on the theoretical ion exchange capacity of an irradiated homopolymer having only the same -A- recurring units.
15. The method of claim 1 , wherein the polycationic colorant is a polycationic dye that is selected from the group consisting of a cyanine dye, merocyanine dye, acridine dye, polymethine dye, porphyrin dye, phthalocyanine dye, triarylmethane dye, and basic dye.
16. An intermediate article comprising a substrate and having disposed thereon a dry polymeric layer comprising exposed regions and non-exposed regions,
the exposed regions of the dry polymeric layer comprising a crosslinked and neutralized copolymer comprising reacted -A- recurring units and reacted -B- recurring units, and neutralized pendant sulfonic acid groups in the reacted -A- recurring units to which a polycationic colorant is ionically bound, and
the non-exposed regions of the dry polymeric layer comprising a non-crosslinked copolymer that comprises a backbone of at least -A- and -B- recurring units arranged randomly along the backbone, the -A- recurring units comprising pendant groups that are capable of providing pendant aromatic sulfonic acid groups upon irradiation at radiation having a λ max of at least 150 nm and up to and including 450 nm, the -A- recurring units being present in the copolymer in an amount of up to and including 98 mol % based on total copolymer recurring units, and the -B-recurring units comprising pendant groups that can provide crosslinking upon generation of the pendant aromatic sulfonic acid groups in the -A- recurring units, the -B- recurring units being present in an amount of at least 2 mol %, based on total copolymer recurring units, and
the non-exposed regions of the dry polymeric layer also having the polycationic colorant adsorbed thereto.
17. An article comprising a substrate and having disposed thereon a dry polymeric layer comprising exposed and non-exposed regions,
the exposed regions of the dry polymeric layer comprising a crosslinked and neutralized copolymer comprising reacted -A- recurring units and reacted -B- recurring units, and neutralized pendant sulfonic acid groups in the reacted -A- recurring units to which a polycationic colorant is ionically bound, and
the non-exposed regions of the dry polymeric layer comprising a non-crosslinked copolymer that comprises a backbone of at least -A- and -B- recurring units arranged randomly along the backbone, the -A- recurring units comprising pendant groups that are capable of providing pendant aromatic sulfonic acid groups upon irradiation to radiation having a λ max of at least 150 nm and up to and including 450 nm, the -A- recurring units being present in the non-crosslinked copolymer in an amount of up to and including 98 mol % based on total non-crosslinked copolymer recurring units, and the -B- recurring units comprising pendant groups that can provide crosslinking upon generation of the aromatic sulfonic acid groups in the -A-recurring units, the -B- recurring units being present in the non-crosslinked copolymer in an amount of at least 2 mol %, based on total non-crosslinked copolymer recurring units, and
the non-exposed regions of the dry polymeric layer further comprising negatively-charged colloidal particles and adsorbed polycationic colorant.
18. An article comprising a substrate and having disposed thereon a dry polymeric layer comprising exposed and non-exposed regions,
the exposed regions of the dry polymeric layer comprising a crosslinked and neutralized copolymer comprising neutralized pendant sulfonic acid groups to which are adhered positively-charged colloidal particles, and
the non-exposed regions of the dry polymeric layer comprising a non-crosslinked copolymer that comprises a backbone of at least -A- and -B- recurring units arranged randomly along the backbone, the -A- recurring units comprising pendant groups that are capable of providing pendant aromatic sulfonic acid groups upon irradiation with radiation having a λ max of at least 150 nm and up to and including 450 nm, the -A- recurring units being present in the non-crosslinked copolymer in an amount of up to and including 98 mol % based on total non-crosslinked copolymer recurring units, and the -B- recurring units comprising groups that can provide crosslinking upon generation of the aromatic sulfonic acid groups in the -A- recurring units, the -B- recurring units being present in the non-crosslinked copolymer in an amount of at least 2 mol %, based on total non-crosslinked copolymer recurring units, and
the non-exposed regions of the dry polymeric layer further comprising adsorbed polycationic colorant.