Formation and characterization of self-assembled films of sulfur-derivatized poly(methyl methacrylates) on gold

Lenk, T. J.; Hallmark, V. M.; Rabolt, John F.; Haeussling, L.; Ringsdorf, Helmut

doi:10.1021/ma00058a005

Cited by 69 publications

(79 citation statements)

References 6 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Similarly to refs. [192,193] less polymer adsorbed with increasing q. However unlike the PMMA system [193] the final layer did not contain unreacted thiols except for the case q = 1.…”

Section: Methodsmentioning

confidence: 83%

Non-equilibrium in adsorbed polymer layers

O’Shaughnessy

Vavylonis

2005

J. Phys.: Condens. Matter

123

152

View full text Add to dashboard Cite

Abstract.High molecular weight polymer solutions have a powerful tendency to deposit adsorbed layers when exposed to even mildly attractive surfaces. The equilibrium properties of these dense interfacial layers have been extensively studied theoretically. A large body of experimental evidence, however, indicates that non-equilibrium effects are dominant whenever monomer-surface sticking energies are somewhat larger than kT , a common case. Polymer relaxation kinetics within the layer are then severely retarded, leading to non-equilibrium layers whose structure and dynamics depend on adsorption kinetics and layer ageing. Here we review experimental and theoretical work exploring these non-equilibrium effects, with emphasis on recent developments. The discussion addresses the structure and dynamics in non-equilibrium polymer layers adsorbed from dilute polymer solutions and from polymer melts and more concentrated solutions. Two distinct classes of behaviour arise, depending on whether physisorption or chemisorption is involved. A given adsorbed chain belonging to the layer has a certain fraction of its monomers bound to the surface, f , and the remainder belonging to loops making bulk excursions. A natural classification scheme for layers adsorbed from solution is the distribution of single chain f values, P (f ), which may hold the key to quantifying the degree of irreversibility in adsorbed polymer layers. Here we calculate P (f ) for equilibrium layers; we find its form is very different to the theoretical P (f ) for non-equilibrium layers which are predicted to have infinitely many statistical classes of chain. Experimental measurements of P (f ) are compared to these theoretical predictions.

show abstract

“…Similarly to refs. [192,193] less polymer adsorbed with increasing q. However unlike the PMMA system [193] the final layer did not contain unreacted thiols except for the case q = 1.…”

Section: Methodsmentioning

confidence: 83%

Non-equilibrium in adsorbed polymer layers

O’Shaughnessy

Vavylonis

2005

J. Phys.: Condens. Matter

123

152

View full text Add to dashboard Cite

show abstract

“…In physisorption, monomer attachment is essentially diffusionlimited, Q ≈ 1/t a , where t a is monomer relaxation time. Chemisorption, where adsorbed monomers form very strong chemical bonds with the surface [73,44,45,46,47,48] is much slower [74,52,75] with Q values 8 or more orders of magnitude smaller than those of physisorption. The origin of this difference is that chemical bond formation usually involves a large activation barrier ( fig.…”

Section: Where ∞ Denotes Asymptotic Values (T → ∞)mentioning

confidence: 99%

“…The extreme example of irreversibility arises in chemisorption [44,45,46,47,48] where covalent surface-polymer bonds develop irreversibly ( fig. 1).…”

Section: Introductionmentioning

confidence: 99%

Irreversible adsorption from dilute polymer solutions

2003

View full text Add to dashboard Cite

Abstract. We study irreversible polymer adsorption from dilute solutions theoretically. Universal features of the resultant non-equilibrium layers are predicted. Two broad cases are considered, distinguished by the magnitude of the local monomer-surface sticking rate Q: chemisorption (very small Q) and physisorption (large Q). Early stages of layer formation entail single chain adsorption. While single chain physisorption times τ ads are typically micro to milli-seconds, for chemisorbing chains of N units we find experimentally accessible times τ ads = Q −1 N 3/5 , ranging from seconds to hours. We establish 3 chemisorption universality classes, determined by a critical contact exponent: zipping, accelerated zipping and homogeneous collapse. For dilute solutions, the mechanism is accelerated zipping: zipping propagates outwards from the first attachment, accelerated by occasional formation of large loops which nucleate further zipping. This leads to a transient distribution ω(s) ∼ s −7/5 of loop lengths s up to a maximum size s max ≈ (Qt) 5/3 after time t. By times of order τ ads the entire chain is adsorbed. The outcome of the single chain adsorption episode is a monolayer of fully collapsed chains. Having only a few vacant sites to adsorb onto, late arriving chains form a diffuse outer layer. In a simple picture we find for both chemisorption and physisorption a final loop distribution Ω(s) ∼ s −11/5 and density profile c(z) ∼ z −4/3 whose forms are the same as for equilibrium layers. In contrast to equilibrium layers, however, the statistical properties of a given chain depend on its adsorption time; the outer layer contains many classes of chain, each characterized by a different fraction of adsorbed monomers f . Consistent with strong physisorption experiments, we find the f values follow a distribution P (f ) ∼ f −4/5 .

show abstract

“…(73,(89)(90)(91)(92)(93) Polymeric materials offer several attractive properties for the formation of organic monolayers (Fig. 4).…”

Section: Polymeric Monolayersmentioning

confidence: 99%

“…Since each polymer unit contains many sulfur-bearing side chains, multiple Au-S bonds will be formed between each polymer molecule and the Au surface. (73,(89)(90)(91)(92)(93) This process results in a significant increase in the stability of the organic molecules. (73,89) In the case of multiple-point attachment, one or more of the Au-S bonds can be broken without the molecule becoming detached because at any time several Au-S bonds will still be intact.…”

Section: Polymeric Monolayersmentioning

confidence: 99%

Chemical Modification of Surfaces

Castner

2002

Specimen Handling, Preparation, and Treatments in Surface Characterization

View full text Add to dashboard Cite

Formation and characterization of self-assembled films of sulfur-derivatized poly(methyl methacrylates) on gold

Cited by 69 publications

References 6 publications

Non-equilibrium in adsorbed polymer layers

Non-equilibrium in adsorbed polymer layers

Irreversible adsorption from dilute polymer solutions

Chemical Modification of Surfaces

Contact Info

Product

Resources

About