Covalent chemical modification of self- assembled fluorocarbon monolayers by low- energy CH2Br2+· ions: a combined ion/surface scattering and X-ray photoelectron spectroscopic investigation

Wade, Nathan; Pradeep, Thalappil; Shen, Jie; Cooks, R. Graham

doi:10.1002/(sici)1097-0231(19990615)13:11<986::aid-rcm595>3.0.co;2-u

Cited by 20 publications

(4 citation statements)

References 54 publications

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“…Surface modification using reactive landing of low-energy (o100 eV) ions has been reported by several groups. Examples include formation of silicon nitride by collisions of low-energy N + and N 2 + ions with a Si(100) surface, 53 formation of Si-O bond between the OH-terminated SAM (HO-SAM) surface and a variety of SiX + ions, [54][55][56] esterification and ether formation on the HO-SAM surface following collisions with C 6 H 5 CO + and C 6 H 5 CH 2 + ions, respectively, 57 chemical modification of FSAM [58][59][60][61] and polystyrene 62 surfaces, growth and modification of thin films, 2,63-65 and covalent immobilization of small molecules and proteins on plasma-treated metal surfaces. 26,28 Peptide-modified surfaces are commonly used in biological and medical applications ranging from characterization of molecular recognition events at the amino acid level and identification of biologically active motifs in proteins to the development of novel biosensors and substrates for improved cell adhesion.…”

Section: Covalent Immobilization Of Peptides Using Reactive Landingmentioning

confidence: 99%

Soft-landing of peptide ions onto self-assembled monolayer surfaces: an overview

Laskin

Wang

Hadjar

2008

Phys. Chem. Chem. Phys.

115

169

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This review is focused on what has been learned in recent research studies concerned with fundamental aspects of soft-landing and reactive landing of peptide ions on self-assembled monolayer surfaces (SAMs). Peptide ions are particularly attractive model systems that provide important insights on the behavior of soft landed proteins, while SAMs provide a convenient and flexible platform for tailoring the interfacial properties of metals and semiconductor surfaces. Deposition of mass-selected ions on surfaces is accompanied by a number of processes including charge reduction, neutralization, covalent and non-covalent binding, and thermal desorption of ions and molecules from the substrate. Factors that affect the competition between these processes are discussed.

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Section: Covalent Immobilization Of Peptides Using Reactive Landingmentioning

confidence: 99%

Soft-landing of peptide ions onto self-assembled monolayer surfaces: an overview

Laskin

Wang

Hadjar

2008

Phys. Chem. Chem. Phys.

115

169

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“…Scattered and sputtered ion data have been used to show that various polyatomic ions will ''soft land'' as intact species upon FC surfaces at ϳ10 eV collision energies 17 and induce other types of covalent surface modification above 20 eV. 77 However, selective ionization effects prevent quantification of surface chemistry from scattered or sputtered ions, thereby complicating comparison with our results. Finally, Ͻ100 eV ion-surface scattering tends to sample the repulsive wall of the ion-surface scattering potential, thereby emphasizing mechanical effects of the collision while suppressing chemical effects that occur on the attractive portion of the potential.…”

Section: Energy Transfer In Ion-surface Collisionsmentioning

confidence: 99%

Effect of polyatomic ion structure on thin-film growth: Experiments and molecular dynamics simulations

Wijesundara

Yuan

et al. 2000

Journal of Applied Physics

111

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The experiments described here examine 25-100 eV CF 3 ϩ and C 3 F 5 ϩ ion modification of a polystyrene ͑PS͒ surface, as analyzed by x-ray photoelectron spectroscopy. The molecular dynamics computer simulations probe the structurally and chemically similar reactions of 20-100 eV CH 3 ϩ and C 3 H 5 ϩ with PS. CF 3 ϩ and C 3 F 5 ϩ each form a distribution of different fluorocarbon ͑FC͒ functional groups on PS in amounts dependent upon the incident ion energy, structure, and fluence. Both ions deposit mostly intact upon the surface at 25 eV, although they also undergo some crosslinking upon deposition. Fragmentation of the two ions increases as the ion energies are increased to 50 eV. Both ions show increases in total fluorine and fluorinated carbon content when changing the ion energy from 25 to 50 eV. The simulations predict that CH 3 ϩ and C 3 H 5 ϩ behave in a similar fashion to their FC analogs, remaining mostly intact and either embedding or scattering from the surface without reacting at 20 eV. At 50 and 100 eV, the simulations predict fragmentation most or all of the time. The simulations also show that the chemical products of the collisions depend significantly on the structure of the incident isomer. The simulations further illustrate how the maximum penetration depth of ion fragments depends on ionic structure, incident energy, and the identity of the penetrating fragment. These ion-surface results are discussed in terms of their possible role in plasmas.

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“…It was further demonstrated that these ion–surface reactions chemically altered the surface molecular groups. For example, a transhalogenation reaction, performed with reagents such as PCl 3 + or Si(NCO) + , has been shown to transform fluorocarbon surfaces chemically into terminal CF 2 X units, where X represents the halogen atom or pseudohalogen in the projectile ion 32–34. The scattered ion beam then includes such reaction products as PCl 2 F + .…”

Section: Introductionmentioning

confidence: 99%

Silylation of an OH‐terminated self‐assembled monolayer surface through low‐energy collisions of ions: a novel route to synthesis and patterning of surfaces

Wade

Evans

et al. 2002

J. Mass Spectrom.

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Using a multi-sector ion-surface scattering mass spectrometer, reagent ions of the general form SiR(3) (+) were mass and energy selected and then made to collide with a hydroxy-terminated self-assembled monolayer (HO-SAM) surface at energies of approximately 15 eV. These ion-surface interactions result in covalent transformation of the terminal hydroxy groups at the surface into the corresponding silyl ethers due to Si--O bond formation. The modified surface was characterized in situ by chemical sputtering, a low-energy ion-surface scattering experiment. These data indicate that the ion-surface reactions have high yields (i.e. surface reactants converted to products). Surface reactions with Si(OCH(3))(3) (+), followed by chemical sputtering using CF(3) (+), yielded the reagent ion, Si(OCH(3))(3) (+), and several of its fragments. Other sputtered ions, namely SiH(OCH(3))(2)OH(2) (+) and SiH(2)(OCH(3))OH(2) (+), contain the newly formed Si--O bond and provide direct evidence for the covalent modification reaction. Chemical sputtering of modified surfaces, performed using CF(3) (+), was evaluated over a range of collision energies. The results showed that the energy transferred to the sputtered ions, as measured by their extent of fragmentation in the scattered ion mass spectra, was essentially independent of the collision energy of the projectile, thus pointing to the occurrence of reactive sputtering.A set of silyl cations, including SiBr(3) (+), Si(C(2)H(3))(3) (+) and Si(CH(3))(2)F(+), were similarly used to modify the HO-SAM surface at low collision energies. A reaction mechanism consisting of direct electrophilic attack by the cationic projectiles is supported by evidence of increased reactivity for these reagent ions with increases in the calculated positive charge at the electron-deficient silicon atom of each of these cations. In a sequential set of reactions, 12 eV deuterated trimethylsilyl cations, Si(CD(3))(3) (+), were used first as the reagent ions to modify covalently a HO-SAM surface. Subsequently, 70 eV SiCl(3) (+) ions were used to modify the surface further. In addition to yielding sputtered ions of the modified surface, SiCl(3) (+) reacted with both modified and unmodified groups on the surface, giving rise not only to such scattered product ions as SiCl(2)OH(+) and SiCl(2)H(+), but also to SiCl(2)CD(3) (+) and SiCl(2)D(+). This result demonstrates that selective, multi-step reactions can be performed at a surface through low-energy ionic collisions. Such processes are potentially useful for the construction of novel surfaces from a monolayer substrate and for chemical patterning of surfaces with functional groups.

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Covalent chemical modification of self- assembled fluorocarbon monolayers by low- energy CH2Br2+· ions: a combined ion/surface scattering and X-ray photoelectron spectroscopic investigation

Cited by 20 publications

References 54 publications

Soft-landing of peptide ions onto self-assembled monolayer surfaces: an overview

Soft-landing of peptide ions onto self-assembled monolayer surfaces: an overview

Effect of polyatomic ion structure on thin-film growth: Experiments and molecular dynamics simulations

Silylation of an OH‐terminated self‐assembled monolayer surface through low‐energy collisions of ions: a novel route to synthesis and patterning of surfaces

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