Bottom-up fabrication via polymer brush hypersurface photolithography

Abstract

A surface for use in photolithography. The surface has a layer of a copolymer that is the polymerization product of a divinyl monomer, a polythiol monomer and a monovinyl monomer. The copolymer is covalently bound to the surface by a mercaptan group. The monovinyl monomer chelates a metal ion which is reduced to the corresponding metal nanoparticle.

Description

BOTTOM-UP FABRICATION VIA POLYMER BRUSH HYPERSURFACE PHOTOLITHOGRAPHYCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims priority to, and is a non-provisional of, U. S. Patent Applications 63 / 652,497 (filed May 28, 2024) and 63 / 761,049 (filed February 20, 2025), the entirety of which are incorporated herein by reference.STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

[0001] This invention was made with government support under grant numbers DBI-2032176 awarded by the National Science Foundation, FA9550-23-1-0230, DGE- 2151945 and FA9550-22-1-0513 awarded by the Air Force Office of Scientific Research, W911NF-23-1-0234 awarded by the Office of the Secretary’ of Defense; EES-2112550 and LEAD-HI 2245265 awarded by the National Science Foundation. The government has certain rights in the invention.BACKGROUND OF THE INVENTION

[0002] There is a growing need for lithography methods that can create transparent and conductive (T / C) patterns for flexible electronics, solar cells, smart windows, touch screens, augmented / virtual reality displays, implants, and sensors, particularly those involving optical detection. In solar cells, these patterns allow light to reach the active layer while providing a mechanism for collecting and transporting charge carriers. In touch screens, tablets, smartphones, and interactive kiosks, T / C patterns provide pathways for charge transport while maintaining the screen’s clarity and responsiveness. These patterns ensure that electrical signals can pass through without disrupting the visual display, while still allowing for smooth and accurate touch sensitivity.Furthermore, their flexibility and durability are essential for withstanding repeated use and ensuring long-term device performance, even in flexible or foldable screens. Optical sensors that conform to the human body require flexible and stretchable T / C materials tomaintain both electrical conductivity and optical functionality during movement. These applications often require that the T / C patterns are applied onto substrates, including glass, plastics, or textiles, which are not substrates typical for conventional microfabrication approaches. To fabricate the next generation of electronic, wearable devices, there is a pressing need for lithography methods that can prepare T / C patterns on diverse substrates.

[0003] Despite the growing need, the preparation of T / C patterns and, in turn, the widespread adoption of devices that incorporate such patterns, faces several challenges related to substrate chemistry compatibility, difficulty in creating surfaces that combine soft and hard materials, and the slow throughput of the design-test-optimization cycle. T / C patterns are produced most frequently using top-down techniques like sputtering or chemical vapor deposition (CVD), and solution-based methods such as spin and spray coating. CVD involves depositing a thin metallic film through a mask onto a substrate, but this process often requires high temperatures and vacuum conditions that may be incompatible with soft materials or certain substrates. The spin coating of thin films is scalable, but involves additional steps, such as masking or surface modification to create patterns. Combining these methods to tailor the electrical properties within a pattern poses significant challenges, particularly when integrating soft (organic, polymeric, and biological) and hard (inorganic and metallic) materials. This integration can lead to poor adhesion, cracking, or delamination, adversely affecting the film’s conductivity and mechanical properties. Such issues are especially critical for applications requiring biotic and abiotic integration, like bioelectronics or wearable devices, where flexibility and biocompatibility are crucial. Alternatively, bottom-up approaches build stmctures from smaller components through self-assembly or controlled deposition. These methods, such as templated self-assembly of nanoparticles (NPs), offer nanoscale precision without extensive material removal and allow for tailored material integration and patterning. However, many bottom-up techniques require further optimization to achieve high throughput and scalability over large areas. Moreover, these methods involve multiple steps and specialized equipment, often necessitating clean room environments, whichlimits accessibility. Finally, the low throughput of preparing and characterizing these films, often yielding only a few samples per day or per processing sequence, hinders the testing and optimization cycle involved in the development of new film and processing conditions. Therefore, there is a continued need for lithographic methods that can print T / C patterns, accommodate different materials, and can print over large (>1 cm2) areas with high throughput.

[0004] Many of these drawbacks could be addressed with the use of patterned polymer brushes. This approach involves grafting polymers onto or from a surface and then modifying the resulting polymer brushes with conductive elements, such as gold nanoparticles (AuNPs), or alternatively, the polymer brushes themselves are conductive. By leveraging techniques such as surface-initiated photopolymerization (SIP), patterns can be fabricated with sub-3 micrometer precision over large areas while accommodating various materials within the pattern design. The advantages of using polymer brushes include the ability to create a uniform, defect-free coatings and the versatility to modify surface properties by adjusting the polymer composition and brush height, h. In addition, the brushes can be grafted covalently to the surfaces, ensuring a strong attachment to the substrate.

[0005] To date, significant progress has been made in creating conductive polymer brush patterns using various photolithographic techniques. However, one of the significant challenges with these patterns, particularly when polymer brushes are involved, is achieving sheet resistance (Rs) below 10 Ω sq−1for high-performance applications, such as optical detection systems or solar cells, and 10 to 100 Ω sq−1required for uses in flexible electronics, touch screens, and displays. For example, researchers have used surface-initiated photopolymerization to create conductive polymer brushes, such as poly(monomethyl itaconate) (PMMI) grafted multi-layer graphene oxide (PMMI-g-GO) and poly(4-vinylaniline) nanospheres, and in doing so have achieved materials with electrical conductivity as high as 5.04 S m1(Rs:::1.98 x 10’ Q sq"1, for a 1 pm thick layer) and 3 * 101S cm"1(Rs8 12 10’ sq"1, for a shell thickness of 41 nm), respectively. Another significant advancement is block copolymer lithography,which combines the self-assembly of block copolymers with photolithographic techniques to create nanoscale patterns. This approach has been employed to produce highly ordered, periodic patterns of polymer brushes with conductive domains. Notably, the incorporation of conductive polymers like poly(3-hexylthiophene) (P3HT) has demonstrated good electrical performance. P3HT’s crystallinity helps form efficient charge transport pathways, even at low concentrations (as low as 3 wt%), without degrading the device’s performance. However, this crystallinity renders it difficult to achieve desirable transparency because of light scattering, the challenge of uniform integration when mismatched surface interactions may occur, and the inability to immobilize into arbitrary, multiplexed patterns because of the limitations of the lithographic methods.

[0006] Organic polymer brushes themselves often have unsatisfactory conductivity for electronic applications because of the insulating nature of most organic polymer matrices. Previously this challenge has been addressed by incorporating conductive additives into patterns, including metal NTs, such as AuNPs, CuNPs, and AgNPs, or carbon nanotubes, Ag nanowires, or conductive polymers in an attempt to increase conductivity. For example, Ag nanowire additives can achieve sheet resistances of 10 Ω sq−1with over 90% transparency, making them one of the best performers for applications requiring high conductivity, flexibility, and transparency. Additionally, metal NP-polymer composite films have demonstrated excellent conductivity when structured as multilayered architectures. Polymeric materials serve as both substrates and binders for metal NPs, allowing for precise structural control and enhanced conductivity. For instance, a multilayer polymer-metal film has been reported to achieve a sheet resistance of 5 Ω sq−1with 78% transmittance, while an oxide / metal / polymer composite exhibited 15.1 Ω sq−1with 87.4% transmittance. These results demonstrate that incorporating polymer-metal hybrid structures can lead to highly conductive films while maintaining excellent optical transparency. However, these approaches have often struggled with achieving uniform distribution and integration of conductive materials, highlighting the need for more advanced and precise fabrication techniques. AuNPs,known for their exceptional electrical conductivity, chemical stability, and biocompatibility, are particularly promising candidates for enhancing the conductivity of these polymer brush films. In sputtered Au films, sheet resistivity as low as about 10−5Ω cm (10 Ω sq−1) have been reported for continuous films with thicknesses around 10 nm, and this value is only one order of magnitude higher than that of the resistivity of bulk gold, 2.44 x 10"6Q cm (2.44 Q sq”1) at that thickness, demonstrating that such films could offer attractive conductivity if further optimized. The challenge of achieving AuNP / polymer brush composites with low Rsis that precise control over the size, shape, and surface chemistry of the NPs is necessary to ensure integration in sufficiently high concentrations to achieve desirable conductivity (<1 Q sq"1) for high-performance applications. Furthermore, the high concentrations of AuNPs necessary for low Rs can compromise the film’s transparency, limiting their effectiveness in applications where both transparency and conductivity are crucial. Additionally, the low throughput of current fabrication processes hinders the synergistic exploration of the relationships between polymer architecture, AuNP integration, conductivity, and transparency required to optimize these fabrication processes. Until these problems are solved, the promise of AuNP / polymer-brush composites as T / C elements in electronic circuits will remain unrealized.

[0007] The discussion above is merely provided for general background information and is not intended to be used as an aid in determining the scope of the claimed subject matter.SUMMARY

[0008] Thi s disclosure provides a surface for use in photolithography. The surface has a layer of a copolymer that is the polymerization product of a divinyl monomer, a poly thiol monomer and a monovinyl monomer. The copolymer is covalently bound to the surface by a mercaptan group The monovinyl monomer chelates a metal ion which is reduced to the corresponding metal nanoparticle. The technical problem to be solved is creating transparent and conductive metal patterns on arbitrary substrates.

[0009] In a first embodiment, a surface is provided. The surface comprises a layer of copolymer that is the polymerization product of a reaction mixture comprising a divinyl monomer, a polythiol monomer and monovinyl monomer, a metal ion, wherein the monovinyl monomer is configured to chelate the metal ion and the copolymer is covalently bound to the surface by a mercaptan group.

[0010] In a second embodiment, a surface is provided. The surface comprises a layer of copolymer that is the polymerization product of a reaction mixture comprising a divinyl monomer, a polythiol monomer and monovinyl monomer, a metal nanoparticle, wherein the copolymer is covalently bound to the surface by a mercaptan group.

[0011] In a third embodiment, a surface is provided. The surface comprises a layer of copolymer that is the polymerization product of a reaction mixture comprising an ethylene glycol dimethylacrylate (EGDMA), a pentaerythritol tetrakis(3- mercaptopropionate) (PETT), a monovinyl monomer selected from the group consisting of 2-vinyl pyridine and a 2-vinyl pyrrolidine, and a metal ion or a metal nanoparticle, wherein the copolymer is covalently bound to the surface by a mercaptan group.

[0012] This brief description of the invention is intended only to provide a brief overview of subject matter disclosed herein according to one or more illustrative embodiments, and does not serve as a guide to interpreting the claims or to define or limit the scope of the invention, which is defined only by the appended claims. This brief description is provided to introduce an illustrative selection of concepts in a simplified form that are further described below in the detailed description. This brief description is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. The claimed subject matter is not limited to implementations that solve any or all disadvantages noted in the background.BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The patent or application file contains at least one drawing executed in color. Copies of this patent or patent application publication with color drawing(s) will be provided by the Office upon request and payment of the necessary fee.

[0014] So that the manner in which the features of the invention can be understood, a detailed description of the invention may be had by reference to certain embodiments, some of which are illustrated in the accompanying drawings. It is to be noted, however, that the drawings illustrate only certain embodiments of this invention and are therefore not to be considered limiting of its scope, for the scope of the invention encompasses other equally effective embodiments. The drawings are not necessarily to scale, emphasis generally being placed upon illustrating the features of certain embodiments of the invention. In the drawings, like numerals are used to indicate like parts throughout the various views. Thus, for further understanding of the invention, reference can be made to the following detailed description, read in connection with the drawings in which:

[0015] FIG. 1 A depicts components involved in the bottom-up printing of T / C wires using the grafted-to / grafted-from radical photopolymerization (GTGFRP).

[0016] FIG. IB depicts a hypersurface photolithography printer in use.

[0017] FIG 1C depicts 2VP-EGDMA-PETT polymer brushes on thiol -terminated Si / SiO2 surface bind Au ions.

[0018] FIG. 1D shows the formation of gold nanoparticles (AuNPs) upon reduction of the Au ions.

[0019] FIG. 1E illustrates measuring Rsof polymer-brush patterns.

[0020] FIG. 2A shows preparation of 2VP-EGDMA-PETT polymer brushes via the GTGFRP.

[0021] FIG. 2B shows an optical image of 2VP-EGDMA-PETT polymer brushes patterned onto a thiol-functionalized Si / SiO2wafer. Scale bar is 200 μm

[0022] FIG. 2C is a plot of h versus t of the brushes shown in FIG. 2B.

[0023] FIG. 2D depicts XI’S spectrum (N1 s) of polymer brush patterns 2VP- EGDMA-PETT polymer brushes and EGDMA-PETT polymer brush features.

[0024] FIG. 2E shows Time-of-flight secondary ion mass spectrometry spectra of EGDMA-PETT and 2VP-EGDMA-PETT

[0025] FIG. 2F is an optical image of pattern containing 2VP-EGDMA-PETT polymer brushes (squares) and EGDMA-PETT polymer brushes (circle) that do not contain 2 VP and cannot bind Au ions. Scale bars are 100 pm.

[0026] FIG. 2G is a SEM image of polymer brushes in FIG. 2F. Scale bars are 250 pm

[0027] FIG. 2H is Raman spectroscopy map of polymer brushes in FIG. 2F. Scale bars are 100 pm.

[0028] FIG. 21 is a SEM7EDS image of Au Mcrl of the polymer brushes in FIG 2F. Scale bars are 250 pm.

[0029] FIG. 2J shows a XPS spectrum of Au4f of the passivated 2VP-EGDMA- PETT polymer brushes, a passivated thiol-functionalized surface, and MA-passivated surfaces with EGDMA-PETT polymer brushes that do not contain the 2VP groups.

[0030] FIG. 3 A is an optical image of 2VP-EGDMA-PETT polymer brush lithography test pattern with profilometry trace indicating the h of each feature. The x- axis units are in mm and y-axis units are in pm. Scale bars are 900 pm.

[0031] FIG. 3B shows a fluorescent micrograph of rhodamine B methacrylate (RMA) functionalized polymer brush lithography test pattern with profilometry trace indicating the h of each feature on the corresponding row. The x-axis units are in mm and y-axis units are in pm. Scale bars are 900 μm.

[0032] FIG. 3C depicts an image of a fire dragon with glowing red eyes. Raman map of a 2VP-EGDMA-PETT and RMA-EGDMA-PETT multiplexed polymer brush pattern. Area scans were taken with 532 nm lasers and 633 nm laser for measuring Au and RMA peaks, respectively, and the image of the fire dragon is produced by overlaying the two Raman maps. Yellow show's peak intensities at 10-350 cm1(Aex= 532 nm). Red shows peak intensities at 1400-1460 cm’1(Aex= 633 nm). Scale bar is 200 pm.

[0033] FIG. 4A shows an optical image of 2VP-EGDMA-PETT polymer brushes bound to AuNPs prepared via in situ reduction on a thiol-functionalized glass surface passivated with maleic anhydride. Scale bar is 900 pm.

[0034] FIG. 4B depicts a Raman map (Aex= 532 nm) of peaks corresponding to Au (310-350 cm’1) of 2VP-EGDMA-PETT polymer brushes with intercalated AuNPs. Scale bar is 1000 gm.

[0035] FIG. 4C is a SEM image of 2VP-EGDMA-PETT polymer brushes bound to AuNPs patterned on a thiol-functionalized glass surface. Scale bar is 1 μm. Inset is SEM / EDS image of AuMα1 intensity (green). Inset scale bar is 25 pm.

[0036] FIG. 4D depicts an UV-Vis absorbance spectrum of 2VP-EGDMA-PETT polymer brushes patterned on a thiol-functionalized glass surface.

[0037] FIG. 4E depicts a graph of transmittance data taken from the samples in FIG. 4D.

[0038] FIG. 4F is a graph showing sheet resistance (Rs) versus current (I) plot of different samples measured by a 4-point probe device.

[0039] FIG. 4G is an expansion of plot of FIG. 4F showing Rsfrom I = 650–1050 mADETAILED DESCRIPTION OF THE INVENTION

[0040] This disclosure addresses the challenges of creating T / C AuNP / polymer brush composite patterns with Rs< 1 Q sq“]by combining hypersurface photolithography (HP), the grafted to / grafted-from radical photopolymerization (GTGFRP), and bottom- up, templated AuNP self-assembly. A polymer brush hypersurface refers to a printed structure where multiple independent properties of each voxel can be precisely controlled. Polymer brushes with Au-binding 2-vinyl pyridine (2VP) groups were grafted from Si / SiO2 and glass surfaces. These structures were then incubated in a solution of Au ions, and subsequently reduced to create AuNP / polymer-brush composite patterns. The ability of hypersurface photolithography to test polymer brush growth conditions with ultra-high throughput, enabling the screening of hundreds-to-thousandsQof conditions in a single experiment, was used to optimize surface-initiated photopolymerization conditions, so relationships between polymer architecture, metal incubation and reduction, conductivity, and transparency could be explored systematically. The result is patterns with micrometer-scale line widths and Rsas low as 0.42 Q sq on both silicon wafers and glass substrates, and whose conductance is independent of the underlying surface. Additional multiplexed patterns were created by copatterning AuNP / polymer brush composites and fluorescent polymer brushes containing Rhodamine B methacrylate monomers onto the same substrate. This approach enabled the successful production of multiplexed, arbitrary patterns without the need for masks, while effectively blending soft and hard materials within the same structure. This significantly advances the field of bottom-up, mask-free lithography by enabling rapid, high-throughput testing and optimization of AuNP / polymer brush composites, paving the way for the development of high performance, multiplexed, and T / C patterns for various optical and electronic applications.

[0041] Patterning Au-Binding Polymer Brushes with Independent Control over Height at Each Pixel

[0042] Hypersurface photolithography (FIG. IB and FIG. 1C) combines a light emitting diode (LED), such as a 405 nm LED, and a digital micromirror device (DMD) with individually addressable mirrors (e.g. about 700,000 mirrors), and a fluid cell, where surface-initiated photopolymerizations occur, with integrated microfluidic control of reagents to create multiplexed polymer brush patterns. By coordinating the microfluidics with the delivery of light, the brush height / ?, the chemical composition at each pixel (a pixel corresponding to an individual mirror in the DMD), or the reaction condition at each pixel are controlled independently. In some embodiments, the brush height h is from 5 nm to 100 / / m or 1 μm–100 μm.

[0043] As a result, thousands of different reaction conditions can be tested on each printed substrate, allowing for the rapid screening of reaction conditions and high- throughput optimization of surface chemistry To this end, hypersurface photolithography was used to study the kinetics of grafted-from photopolymerizations,create stimuli-responsive hypersurfaces, and create biosensors with attomolar sensitivity. Here, hypersurface photolithography was first used to study the growth rates of 2VP- containing polymer brushes grown by the GTGFRP. The GTGFRP is a living, photochemically driven thiol-initiated radical photopolymerization, where branched polymer brushes composed of ethylene glycol di methacryl ate (EGDMA) and pentaerythritol tetrakis(3 -mercaptopropionate) (PETT) monomers are grafted from a thiol-terminated substrate.

[0044] By adding molecules with terminal alkenes to the reaction solution, functional groups are incorporated into the growing polymer brush via covalent C-S bonds. In this process, 2 VP is introduced into the printing solution as part of the polymerization and, as a result, 2VP is incorporated throughout the polymer brush structure. This results in 2VP-EGDMA-PETT polymer brushes that are immobilized covalently onto the surface and with the ability to bind metal ions throughout.

[0045] This di sclosure provides a surface that is transparent and conductive. The surface comprises a layer of a copolymer bound to the surface wherein the copolymer is the product of a polymerization reaction between a divinyl monomer, a. poly thiol monomer and monovinyl monomer. See, for example, FIG. 1A. The monovinyl monomer provides a ligand that chelates a metal ion (e.g. an ion of Au, Ag, Al, Ca, Cr, Zn, In, Sn, Hf, Ir, Pb, Ni, Cd, Pd, Pt, Cu, Fe, Ni or a combination thereof). The metal ion is reduced to provide the corresponding metal as a nanoparticle. As used in this specification, the term “nanoparticle” refers to particles with an average diameter of 1-100 nm. The presence of the metal nanoparticles render the surface electrically conductive As used in this specification, the term “transparent” refers to a substrate that has at least 70% average transmittance over a wavelength range of 600 nm to 700 nm or at least 60% average transmittance over a wavelength range of 400 nm to 700nm. As used in this specification, the term “conductive” refers to a substrate that has a sheet resistance (R.s) of less than 1 Ω sq−1or less than 0.1 Ω sq−1.[0046[ The divinyl monomer may be an acrylate of Formula A, wherein R5is hydrogen, methyl, ethyl, n-propyl or isopropyl and R8is a linking group. R8may be, forexample, a C1-C8 alkane (see Formula A-I, wherein I is an integer from 1 to 8) or an oligoethylene glycol (see Formula A-2, wherein m is an integer from 1-4). The divinyl monomer functions as a crosslinking agent.Formula AFormula A-lFormula A-2

[0047] In another embodiment, the divinyl monomer is a diacrylate of Formula B, wherein R4is hydrogen, methyl, ethyl, n-propyl or isopropyl and a is an integer selected from 1, 2, 3 and 4. In one such embodiment, the diacrylate is ethylene glycol dimethylacrylate (EGDMA, Formula B-l), wherein a is 2 and R4is methyl.Formula BFormula B-l, EGDMA

[0048] The polythiol monomer has at least two thiol groups (e.g. 2, 3, 4, 5, 6 thiol groups, etc.). The polythiol monomer may be a polythiol of Formula C, wherein e is an integer selected from 2, 3 and 4, d is an integer selected from 0, 1, 2 or 3 and f is an integer given by 4-e. For example, in one embodiment, the polythiol is a dithiol (wherein e=2, f=2), a trithiol (wherein e=3, f=l) or a tetrathiol (wherein e=4, f=0). In one embodiment, the polythiol is 3,3-bis(2-mercaptoethy[)pentane-l,5-dithiol given byFormula C-1 (e=4, d=2 and f=0) which is an example of a tetrathiol. The polythiol monomer functions as a crosslinking agent.CHf'^‘(CH2)dSH | Formula CFormula C-1

[0049] In another embodiment, the polythiol monomer is a dithiol of Formula D, wherein h is an integer selected from 1, 2, 3 and 4. Specific examples of embodiments of Formula D are also provided.HS(CH2)hSH Formula DFormula D-l1,2-ethanedithiolHSx / X^SHFormula D-21,3-propanedithiolHS'SHFormula D-31,4-butanedithiol

[0050] In one embodiment, the polythiol monomer is a polythiol of Formula E wherein d is an integer selected from 0, 1, 2 or 3, j is an integer selected from 1, 2 and 3, i is an integer given by 3-j, and R6is selected from methyl, ethyl, n-propyl and isopropyl.R6—CHf—[(CH2)dSH Formula EjFormula E-l1,1,1 -tri s(mercaptomethyl)ethaneFormula E-21,1, l-tris(mercaptoethyl)ethane

[0051] The polythiol monomer may be a polythiol of Formula F, wherein e is an integer selected from 2, 3 and 4, d is an integer selected from 0, 1, 2 or 3 and f is an integer given by 4-e.Formula FeFormula F-1tetrakis(2-mercaptoethyl)orthocarbonate

[0052] The polythiol monomer may be a pentathiol of Formula G, wherein k is an integer selected from 1, 2, 3 and 4.Formula GFormula G-l

[0053] In another embodiment, the polythiol monomer is a polythiol of Formula H, wherein e is an integer selected from 2, 3 and 4, d is an integer selected from 0, 1, 2 or 3and g is an integer selected from 1, 2, and 3. In one such embodiment, the polythiol is a tetrathiol given by Formula H-l, In one embodiment, the polythiol is pentaerythritol tetrakis(3-mercaptopropi onate) (PETT) given by Formula H-2 (d=2, g=l and f=0).Formula HFormula H-lFormula H-2, PETT

[0054] The monovinyl monomer (e.g., a vinyl monomer, an acrylic acid monomer, an acrylic ester monomer) may be a vinyl arene such as Formula I, wherein R5is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl and X is N or CH. In one embodiment, the vinyl pyridine is 2-vinyl pyridine, given by Formula 1-1 (wherein R5is hydrogen and X is N). In another embodiment, the monovinyl monomer may be a styrene, wherein R5is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl and X is CH. Other embodiments include: 4-vinylpyridine (4VP), N -vinyl carbazole, vinylimidazole, acrylic acid (AA), methacrylic acid (MAA), hydroxyethyl methacrylate (HEMA), etc. The monovinyl monomer provides a ligand that chelates the metal ions but does not provide crosslinking functionality (i.e. non-crosslinking agent).Formula IFormula 1-1, 2 VPFormula 1-2Formula 1-3

[0055] The monovinyl monomer may be a vinyl pyridine such as Formula J, wherein R5is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl.Formula JFormula J-14-vinylpyridine (4VP)

[0056] The monovinyl monomer may be a vinyl carbazole such as Formula K, wherein R is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl.is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl and R7is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl and a C1-C4 hydroxyalkane (e.g. hydroxyethyl).oJL Formula My OnR?'Formula N, wherein R5is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl. In one embodiment, the vinyl pyrrolidine is 2-vinyl pyrrolidine, given by Formula N-l (wherein R' is hydrogen).Formula N2-vinyl pyrrolidine

[0060] The copolymer is formed on a surface that has exposed mercaptan groups by exposure to light in the presence of a photoinitiator and solvent. Examples of suitable photoinitiators include, diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide (TPO), ethyl (2,4,6-trimethylbenzoyl) phenylphosphinate (TPO-L), bisacylphosphine oxide (BAPO), 2-hydroxy-2-methyl-l -phenylacetone, 1 -hydroxy -cyclohexyl benzophenone, lithium phenyl-2,4,6-trimethylbenzoylphosphinate (LAP), 2,2-dimethoxy-2-phenylacetophenone,benzophenone, Irgacure 2100 (blend of two photoinitiators: ethyl phenyl(2,4,6-trimethylbenzoyl)phosphinate (approximately 95% by weight) and phenyl bis(2,4,6-trimethylbenzoyl)phosphine oxide (approximately 5% by weight)), tris(2-phenylpyridine)iridium (Ir(ppy)3 ), 2-hy droxy-2-methylpropi ophenone, etc

[0061] For example, FIG. 1 A depicts examples of components involved in the bottom-up printing of T / C wires using the grafted-to / grafted-from radical photopolymerization (GTGFRP). FIG. IB shows a hypersurface photolithography (HP) printer used for surface patterning combines a digital micromirror device (DMD), a microfluidics-enabled fluid cell, and a reactive surface. This provides patterned polymer brushes growing from a thiol-terminated Si / SiO2surface by consuming monomers in solution upon exposure to light. As the irradiation time, / , increases, the height, h, of the polymer brushes increases. FIG. 1C shows 2VP-EGDMA-PETT polymer brushes on thiol-terminated Si / SiO2surface with bound Au ions. FIG. ID shows the formation of gold nanoparticles (AuNPs) formed upon reduction of Au-ions. FIG. IE depicts measuring Rsof polymer-brush patterns using a four-point probe.

[0062] The high-throughput screening capabilities of hypersurface photolithography were used to systematically explore the effects of [2 VP], light intensity, and irradiation time, t, on the growth rate of 2VP-EGDMA-PETT polymer brushes, with 576 conditions tested using the same pattern. To print the polymer brush patterns (FIG. 2A), a solution containing EGDMA, PETT, 2 VP, and a photoinitiator (e g. diphenyl(2,4,6- trimethylbenzoyi)phosphine oxide (TPO)) in DMSO was prepared under inert atmosphere and introduced into the fluid cell of the hypersurface photolithography printer. The mixture was then irradiated with 4 μm x 500 μm line patterns of 405 nm light, where each of the 12 lines within a pattern was irradiated at t from 58 to 80 min. Following the printing, the surfaces were washed with EtOH and air-dried to remove any physiosorbed monomers. The presence of the printed patterns was confirmed using optical microscopy (FIG, 2B). The height h of each feature was measured using profilometry (FIG. 2C), and the ability to print 12 patterns of 12 lines on each surface produced high-fidelity datasets so variance between lines on different patterns could bemeasured accurately. The heights h were determined by profilometry. Heights are reported as the average of 3 features printed at the same time t, and all error bars are reported as one standard deviation from the mean. The results showed the growth rate of the 2VP-EGDMA-PETT polymer brushes increased as [2VP] increased FIG. 2C shows that at [2VP] = 500 mM, the height h of these polymer brushes can be varied controllably from 8.0 ± 2.5 to 3800 ± 8.7 nm. The polymerization process is influenced by multiple parameters, including [monomer], [photoinitiator], light intensity, and t. Although >9000 conditions were tested, this disclosure only details a fraction of the total parameter space for this reaction. To confirm the presence of 2VP-groups within the polymer brush features, Xray photoelectron spectroscopy (XPS) was performed on a VPEGDMA-PETT polymer brush substrate and compared to a substrate with EGDMA-PETT polymer brushes. A significant Nls signal is observed with the substrate which contained the 2VPEGDMA-PETT polymer brushes (FIG. 2D), which is consistent with the proposed chemical structures of the polymers, but no such peak was observed for the EGDMA- PETT brushes that lack N, indicating that the incorporation of 2 VP into the polymer brushes was successful. FIG. 2D depicts the XPS spectrum (Nls) of polymer brush patterns of 2VP-EGDMA-PETT polymer brashes ([2 VP] = 500 mM; [EGDMA] - 1300 mM; [TPO] = 1 mm; light intensity = 2.53 mW mm−2; [PETT] = 100 mM) and EGDMA-PETT polymer brash features, which were printed without 2VP ([EGDMA]:::1300 mM, [TPO] = 1 mM; light intensity = 2.53 mW mm'; [PETT] = 100 mm). Time-of-flight secondary ion mass spectrometry of the 2 VP -EGDMA-PETT polymer brushes was taken and compared to that of the EGDMA-PETT polymer brashes (FIG. 2E). The mass spectra show that the 2VP -EGDMA-PETT surface had peaks with m / z corresponding to the aniline groups of 2VP, which were not present in the spectra of the EGDMA-PETT samples. These results demonstrate the ability to control precisely the height h and chemical composition of the polymer brushes at each feature in the patterns. FIG. 2E, depicts time-of-flight secondary ion mass spectrometry spectra of (bottom) EGDMA- PETT polymer brash features ([EGDMA] ~ 1300 mM; [TPO] = 1 mM; light intensity “ 2.53 mW mm−2; [PETT] = 100 mm), (top): 2 VP -EGDMA-PETT polymer brash features([2VP] = 500 mM; [EGDMA] = 1300 mM; [TPO] = 1 mM; light intensity = 2.53 mW mm−2, [PETT] = 100 mM). Black boxes are at m / z =:106.0, corresponding to the fragment [C7H8N]+. Center: Total ion images are shown. Scale bars are 100 pm.

[0063] Au Ion Binding and In Situ Reduction to Form AuNP / Polymer Brush Composites

[0064] To demonstrate the selective binding of AuNPs to the 2VPEGDMA-PETT polymer brushes, two approaches to incorporating AuNPs into the brushes were tested: incubating presynthesized AuNPs with a surface that had been patterned with 2VP- EGDMA-PETT, and the in situ generation of AuNPs by reduction of Au ions bound to the 2 VP groups on the patterned 2VP-EGDMA-PETT polymer brushes. For the former method, EGDMA-PETT polymer brushes and 2VP-EGDMA-PETT polymer brushes were printed on separate substrates, and these substrates were incubated for 1 h in a solution of pre-synthesized AuNPs (about 30 nm diameter). For the latter method, the polymer brush-modified substrates were first incubated in 0.1 mm HauCU (aq) for 1 h and then reduced with 1 mm NaBFh (aq) for 1 h. These samples were analyzed with XPS to detect the presence of AuNPs onto the different polymers. Results from XPS analysis showed no significant binding of Au to the EGDMA-PETT polymer brushes, irrespective of the incubation method. With in situ AuNP formation the 2VP-EGDMA-PETT polymer brushes showed distinct Au4f peaks at 85 eV, with peak intensity of 410 a.u., confirming Au binding

[0065] The surfaces incubated with AuNPs also displayed Au4f peaks in their XPS spectra, but with a lower peak intensity of 320 a.u. Without wishing to be bound to any particular theory, this lower intensity is believed to be the result of the inability of AuNPs to migrate through the pores of the polymer brush network and bind 2 VP groups within the pillars. To maximize AuNP incorporation with the in situ reduction, the concentration of HauCL was increased to 1 mm, and the NaBEh concentration was increased to 10 mm, which significantly increased the Au4f peak intensities within the 2VP -EGDMA-PETT samples to 3000 a.u. To prevent non-specific Au binding to unreacted thiols on EGDMA-PETT polymer brushes or on the thiol -terminated substrate,the unreacted thiol groups were passivated by incubation of the patterned substrates in a solution of maleic anhydride (MA) for 30 min. After passivation, XPS analysis revealed reduced Au4f peak intensities for the EGDMA-PETT polymer brushes and the thiol- terminated substrates. However, the 2VP-EGDMA-PETT polymer brushes retained high Au4f XPS intensities (3000 a.u.), signifying substantial Au-binding. This increase in Au4F intensity of 2 VP -EGDMA-PETT compared to EGDMA-PETT brushes suggests that the 2 VP units play a desirable role in facilitating Au binding, and that the MA treatment effectively minimizes nonspecific binding to unreacted thiol groups within the brushes and on unpatterned regions of the substrate Varying AuNP size and density is anticipated to affect conductivity and transparency.

[0066] To further demonstrate the selective binding of Au to the 2VPEGDMA-PETT polymer brushes under the in situ AuNP formation conditions, a multiplexed pattern was prepared, where the 2 VP -EGDMA-PETT polymer brushes were printed into squares and the EGDM A-PETT polymer brushes were printed into circles (FIG. 2F) on the same substrate. This multiplexed substrate was passivated with MA followed by a 1 h incubation in 1 M HauCh solution and then reduced with 10 mM NaBHfoaq) for 1 h. An SEM image is shown in FIG. 2G. The substrates were analyzed by Raman mapping to confirm that the Au is bound within the polymer brush pattern by the presence of characteristic Au peaks at 310-350 cm'1(Aex= 532 nm) (FIG 2H). This Raman map, along with the energy-dispersive X-ray spectroscopy (EDS • map of the Au Mα1 intensity (FIG. 2I), confirms that the 2VP-EGDMA-PETT polymer brush regions selectively contained bound Au. The absence of Raman or EDS intensity corresponding to Au in the EGDMA-PETT circles further confirms that the Au ions selectively bind to the 2VP-EGDMA-PETT polymer brushes containing 2VP groups. XPS analyses of these surfaces also confirm the selective binding of Au to the 2VP-EGDMA-PETT polymer brushes (FIG. 2J), with the 2VP-EGDMA-PETT polymer brushes showing a much higher Au4f intensity than that of the EGDMA-PETT brushes or the MA-passivated regions of the thiol terminated SiCh surface.

[0067] Multiplexed Patterning of Au-Binding and Fluorescent Polymer Brushes

[0068] Test patterns in photolithography are prepared so that the widths and roughness of features prepared under different conditions can guide the production of patterns with certain feature dimensions. A test pattern of lines was made that vary in thickness from 5 to 70 gm, which are assembled in groups of four, where in each descending row the spacing between lines varies from 100 to 5 pm, was prepared.

[0069] The first test pattern was printed using 2VP-EGDMA-PETT polymer brushes, and another test pattern was printed with polymer brushes that contain the fluorescent monomer Rhodamine B methacrylate (RMA) by adding RMA to EGDM and PETT during the photopolymerization, resulting in RMAEGDMA-PETT polymer brushes. The profilometry trace of the 2VP-EGDMA-PETT polymer brush test pattern showed that as the spacing between the lines decreases, the h of the brushes increase, and the polymer features merge when spacing is <10 pm (FIG. 3 A). The RMA-EGDMA-PETT polymer brush pattern showed similar results, where, as the spacing between the lines decreased, the polymer brushes grew taller and merged (FIG 3B). From these experiments, it was concluded that line widths ranging from 5 um to 70 p could be printed, and that the distance between non-intersecting lines should be > 10 pm to prevent feature merging. While the resolution is influenced by instrumental factors, such as the size of the mirrors in the DMD and the magnification of the lenses in the hypersurface photolithography printer, it is also possible that chemical properties, including polymer diffusion and crosslinking kinetics, influence pattern resolution.

[0070] Using the guidance from the test patterns, a multiplexed print consisting of 2VP-EGDMA-PETT and RMA-EGDMA-PETT patterned into a fire dragon with fluorescent red eyes was designed (FIG. 3C). Following printing, the substrate was incubated with AuCh(aq) ions (1 mM), reduced with NaBEhfaq) (10 mM), washed, and analyzed by profilometry, optical microscopy, and Raman mapping Two different Raman spectroscopy maps of this pattern were taken, one with a 532 nm laser to observe the Au peaks (310-350 cm’1) within the printed pattern (shown in yellow) and another with 633 nm to detect the RMA (1400-1460 cm ') (shown in red) within the print. Thesetwo different maps were then merged to complete the full image of the fire dragon. RMA peaks were only observed on the eyes (RMA-EGDMA-PETT brushes) and Au peaks were only observed on the lines forming the face (2VP-EGDMA-PETT brushes). The resulting print demonstrates our ability to successfully produce multiplexed, arbitrary patterns, mask-free, and without necessitating cleanroom conditions, while blending soft and hard materials on the same surface and with precisely defined relative positions. This multiplexed print is made possible by the advantages of high throughput optimization, material diversity, and pattern flexibility offered by combining hypersurface photolithography and the GTGFRP[00711 Transparency and Conductivity of AuNP / Polymer Brush Composites

[0072] To analyze the transparency of our Au polymer brush samples, 4 x 3 5 mm rectangular patterns of 2VP-EGDMA-PETT were printed on a thiol-functionalized glass slide. This large pattern was selected to ensure accurate measurement of transparency across the sample. Thi s sample was then passivated with MA, incubated in 1 mM HauCL (aq), and reduced with 10 mM NaBH^aq) to form the AuNP / polynier brush composites. While no pattern is visible by optical microscopy (FIG. 4A), a Raman spectroscopy map of the Au intensities (310-350 cm l, Aex= 532 nm) confirmed the presence of the AuNPs in the pattern (FIG. 4B). SEM images of this pattern were taken to visualize the size of the AuNPs (FIG, 4C), and ImageJ image processing software was used to measure the size of the AuNPs on the surface. These images indicated that the average diameter of the AuNPs was 79 ± 17 nm, where the error is reported as one standard deviation from the mean. The UV-Vis absorbance data supports the size determination of these AuNPs based on the peak at Amax” 580 nm that emerges upon reduction with NaBH4(aq) (FIG. 4D, inset), which corresponds to AuNPs with diameters of 80 nm according to Mie theory' Transmission measurements (FIG. 4E) show an average transmittance of 86% over the wavelength range of 500-800 nm.

[0073] To test the conductivity of these polymer-AuNP composites, a 4-point probe device was designed and fabricated. The device consists of 4 metal pogo pins of 16 mm length with a pin-to-pin spacing of 2.5 mm. The pins w'ere connected and wired using aGH 1.25 mm 4-pin housing, which was then attached to an Agilent B2901A current source and an Agilent 34405A multimeter. To test the accuracy of this device, three different samples of known conductivity were tested, including samples of Ag paint, Cu tape, and an SiOz wafer coated in 50 nm of Au. The Rsof these three materials were consistent with their known conductivities- Ag being the most conductive, followed by Cu, and then Au (FIG. 4F, FIG. 4G). Also, the following non-conductive samples were tested, a glass substrate, an Si / SiOz substrate, and 2VP-EGDMA-PETT polymer brush samples, and their Rsvalues exceeded the maximum sensitivity of the detector of 450 Q sq;

[0074] The AuNP / 2XT-EGDMA-PETT polymer brush samples were prepared on two insulating substrates, thiol-terminated SiO2wafers with 500 nm thermal oxide and transparent thiol-terminated glass slides. On the SiCb substrate, AuNP / 2VP-EGDMA- PETT polymer brushes features were prepared with dimensions of 8 mm x 3.5 mm to ensure contact with all 4 pins Measurements were taken on this Au-ion / 2VP-EGDMA-PETT (2VP Au Ions SiOz) samples (not reduced with NaBH4) to examine whether the reduction from Au ions to AuNPs affected conductivity. The Rsmeasured for a 100 mA input of current on the AuNP / 2VPEGDMA-PETT (2VP AuNP SiO2) polymer brushes sample was 0.38 ± 0.02 Ω sq−1, whereas for the Au-ion / 2VP-EGDMA-PETT polymer brush sample the Rsmeasured was 0.69 ± 0.07 Q sq”1.

[0075] A sample of AuNP / 2 VP-EGDMA-PETT (2VP AuNP Glass) on a glass cover slide was taken, the Rsof 0.42 ± 0.01 fl sq”1at 100 A input showed to be very consistent with that of the AuNP / 2 VPEGDMA-PETT on SiOz (FIG. 4G). For comparison, the sheet resistance of bulk Au for a 1 j m thick sample is 0.0244 Q sq”1. While this study focuses primarily on the fabrication and characterization of T / C polymer-AuNP composites, assessing their long-term stability is essential for practical implementation. To evaluate durability, w?e conducted 250 current input cycles and observed that the films surpassed a sheet resistance of 1Ω sq−1after 148 cycles. The resistance stabilized after 230 cycles, remaining consistent at 1.34 Q sq”1

[0076] The results obtained from the 2VP-EGDMA-PETT-Au polymer brush samples highlight a significant improvement in conductivity when compared to conventional conductive polymers, like (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) (PEDOT), polyaniline (PANI), and polypyrrole (Ppy). Typically, PEDOT, one of the most widely used conductive polymers, exhibits sheet resistivities ranging from 10 to 500 Q sq"1depending on the processing conditions and doping levels. Similarly, PANI and Ppy generally possess Rsin the range of 100–10000 Ω sq−1and 100–1000 Ω sq−1respectively. In contrast, the sheet resistivity of the AuNP / 2VP-EGDMA-PETT samples is < I Q sq"1. These values of Rsunderscore the effectiveness of this lithographic approach towards creating T / C patterns.

[0077] Conclusions: This disclosure demonstrated an approach to fabricating T / C polymer-AuNP composites by combining hypersurface photolithography, the GTGFRP, and templated, in situ AuNP formation. The resulting materials exhibited exceptional performance, with Rsof 0.42 Q sq"1at 100 mA, while maintaining high transmittance from 500 to 800 nm. These properties make these AuNP composites highly suitable for next-generation flexible electronics, sensors, and optical detection devices. Hypersurface photolithography utilizes a microfluidic-based approach for high-throughput materials discovery', enabling the screening of hundreds to thousands of reaction conditions on a single substrate, which can then be translated into other fabrication processes. This disclosure allows for precise control over the polymer brush h and composition, enabling the sy stematic exploration of growth conditions and metal-binding capabilities, and here >9000 different printing conditions were tested to achieve this control. By integrating AuNPs uniformly into the polymer matrix, challenges such as poor adhesion and low conductivity that are typically associated with polymer-based conductive films were overcome. The grafted-from polymer brushes are covalently attached to the substrate, ensuring that these patterns maintain strong, stable interfaces even under various processing conditions. These findings demonstrate that embedding AuNPs within the polymer brush matrix facilitates the formation of conductive pathways.[0078 This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims

What is claimed is:

1. A surface comprising:a layer of copolymer that is the polymerization product of a reaction mixture comprising a divinyl monomer, a polythiol monomer and monovinyl monomer, a metal ion, wherein the monovinyl monomer is configured to chelate the metal ion and the copolymer is covalently bound to the surface by a mercaptan group.

2. A surface comprising:a layer of copolymer that is the polymerization product of a reaction mixture comprising a divinyl monomer, a polythiol monomer and monovinyl monomer, a metal nanoparticle, wherein the copolymer is covalently bound to the surface by a mercaptan group.

3. The surface as recited in claim 2, wherein the monovinyl monomer is selected from the group consisting of a vinyl pyridine monomer, a vinyl pyrrolidine monomer, a vinyl carbazole monomer, a vinyl imidazole monomer and an acrylate monomer with a structure of Formula M:oR^ J-L.7OR'Formula XI.wherein R3is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl and R7is selected from hydrogen, methyl, ethyl, n-propyl, isopropyl and a C1-C4 hydroxyalkane.

4. The surface as recited in claim 2, wherein the monovinyl monomer is selected from the group consisting of a vinyl pyridine monomer, a vinyl pyrrolidine monomer, a vinyl carbazole monomer and a vinyl imidazole monomer.

5. The surface as recited in claim 2, wherein the divinyl monomer has a structure of Formula AFormula Awherein R5is methyl, ethyl, n-propyl or isopropyl and R8is a linking group.

6. The surface as recited in claim 2, wherein the divinyl monomer has a structure of Formula A and the monovinyl monomer has a structure of Formula M:' Formula A,wherein R’ is methyl, ethyl, n-propyl or isopropyl and Rxis a linking group, andFormula M,wherein R5is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl and R'7is selected from hydrogen, methyl, ethyl, n-propyl, isopropyl and a C1-C4 hydroxyalkane.The surface as recited in claim 2, wherein the divinyl monomer has a structure of Formula BFormula Bwherein R4is hydrogen, methyl, ethyl, n-propyl or isopropyl and a is an integer selected from 1, 2, 3 and 4.

8. The surface as recited in claim 2, wherein the divinyl monomer has a structure of Formula B-lO z O Formula B-l9. The surface as recited in claim 2, wherein the polythiol monomer has a structure of Formula CCH<-L / ru ■> cu 1eFormula Cwherein e is an integer selected from 2, 3 and 4, d is an integer selected from 0, 1, 2 or 3 and f is an integer given by 4-e.

10. The surface as recited in claim 2, wherein the polythiol monomer has a structure of Formula HI ° 1CH iC'AV°' Jul"(CH2)dSHeFormula Hwherein e is an integer selected from 2, 3 and 4, d is an integer selected from 0, 1, 2 or 3, g is an integer selected from 1, 2, and 3 and f is an integer given by 4-e.

11. The surface as recited in claim 2, wherein the polythiol monomer has a structure of Formula H-lo pHSW^OTV^O"^SHO O Formula H-l wherein d is an integer selected from 0, 1, 2 or 3 and g is an integer selected from 1. 2, and 312. The surface as recited in claim 2, wherein the polythiol monomer has a structure of Formula H-2o oO O Formula H-2.

13. The surface as recited in claim 2, wherein the monovinyl monomer has a structure of Formula I, Formula J or Formula NFormula N, wherein R5is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl and X is N or CH.

14. The surface as recited in claim 2, wherein the monovinyl monomer has a structure of Formula K or Formula L:wherein R5is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl.

15. The surface as recited in claim 2, wherein the monovinyl monomer has a structure of Formula M:oR5is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl, and R7is selected from hydrogen, methyl, ethyl, n-propyl, isopropyl and a C1-C4 hydroxyalkane.

16. The surface as recited in claim 2, wherein the layer is present on the surface in a predefined pattern such that an image is formed on the surface by the layer 17. The surface as recited in claim 2, wherein the layer and the surface form a composite that is transparent such that the composite has at least 60% average transmittance over a wavelength range of 400 nm to 700nm.

18. The surface as recited in claim 2, wherein the polythiol monomer is selected from the group consisting of pentaerythritol tetraki s(3 -mercaptopropi onate) (PETMP), tetrakis(2-mercaptoethyl)orthocarbonate, 1,2-ethanedithiol, 1,3-propanedithiol, 1,4-butanedithi ol, 1,1,1 -tris(mercaptomethyl)ethane, 1,1,1- tris(mercaptoethyl)ethane, pentakis(mercaptomethyl)cyclopentane, a pentathiolate of a pentaerythritol derivative.

19. The surface as recited in claim 2, whereinthe divinyl monomer has a structure of Formula Bwherein R is hydrogen, methyl, ethyl, n-propyl or isopropyl and a is an integer selected from 1, 2, 3 and 4;the poly thiol monomer has a structure of Formula HeFormula Hwherein e is an integer selected from 2, 3 and 4, d is an integer selected from 0, 1, 2 or 3, g is an integer selected from 1, 2, and 3 and f is an integer given by 4-e;the monovinyl monomer has a structure of Formula I or Formula N:Formula 1, Formula N.wherein R5is selected from hydrogen, methyl, ethyl, n-propyl and isopropyl, wherein X is N or CH.

20. The surface as recited in claim 19, wherein the metal nanoparticle is a gold nanoparticle.

21. The surface as recited in claim 19, wherein the layer comprises brushes with a height of 5 nm to 100 nm.

22. The surface as recited in claim 19, wherein the mercaptan group is continuous with a Si / SiO2substrate.

23. A surface comprising:a layer of copolymer that is the polymerization product of a reaction mixture comprising an ethylene glycol dimethylacrylate (EGDMA), a pentaerythritol tetrakis(3-mercaptopropionate) (PETT), a monovinyl monomer selected from the group consisting of 2-vinyl pyridine and a 2-vinyl pyrrolidine, and a metal ion or a metal nanoparticle, wherein the copolymer is covalently bound to the surface by a mercaptan group.

24. The surface as recited in claim 23, wherein the metal ion or the metal nanoparticle is a metal ion selected from the group consisting of a Au ion, a Ag ion, a Al ion, a Ca ion, a Cr ion, a Zn ion, an In ion, a Sn ion, a Hf ion, an Ir ion, a Pb ion, a Ni ion, a Cd ion, a Pd ion, a Pt ion, a Cu ion, a Fe ion, a Ni ion and a combination thereof.

25. The surface as recited in claim 23, wherein the metal ion or the metal nanoparticle is a gold ion.

26. The surface as recited in claim 23, where the metal ion or the metal nanoparticle is a metal nanoparticle consisting of a metal selected from the group consisting of Au, Ag, Al, Ca, Cr, Zn, In, Sn, Hf, Ir, Pb, Ni, Cd, Pd, Pt, Cu, Fe, Ni or a combination thereof.

27. The surface as recited in claim 24, wherein the metal ion or the metal nanoparticle is a gold nanoparticle.

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