Observation of nano-dewetting structures

Müller‐Buschbaum, Peter; Vanhoorne, Pierre; Scheumann, Volker; Stamm, Manfred

doi:10.1209/epl/i1997-00519-4

Cited by 88 publications

(101 citation statements)

References 19 publications

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“…This scattering technique supplements the force microscopy because GISAXS delivers information about lateral structures all over the illuminated sample area of some mm 2 , while the detection area of SFM is only limited to the range of several µm 2 . The dried layers adsorbed from aqueous polyampholyte solutions containing CsCl were measured at the USAX beam-line BW4 at the DORIS III storage ring at HASYLAB/DESY in-Hamburg (Germany) [31,32] The replacement of NaCl by CsCl in the adsorption solution causes an increased sensitivity of the adsorbed polyampholyte layer to the GISAXS experiments. The response of the adsorbed polymer films increased due to the bigger election density of the coadsorbed ions Cs + compared with Na + .…”

Section: Scanning Force Microscopymentioning

confidence: 99%

Highly Regular Polyampholytic Structures Adsorbed Directly from Solution

Mahltig

Müller‐Buschbaum

Wolkenhauer

et al. 2001

Journal of Colloid and Interface Science

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This article concerns the adsorption of the diblock polyampholyte poly(methacrylic acid)-blockpoly((dimethylamino)ethyl methary-late) (PMAA-b-PDMAEMA) from aqueous solution on silicon substrates. The investigated polyampholyte is characterized by a small molecular weight around 15,000 g/mol and a big positively charged PDMAEMA block. The adsorbed amount determined by ellipsometry was str ongly influenced by the pH of the adsorption solution. Using dynamic light scattering polyampholytic structures with diameters around 50 nm were found in aqueous solution. The hydrodynamic diameter was hardly affected by changing the pH of the polymer solution. Analogous regular structures were also found by scanning force microscopy (SFM) and grazing incidence, small angle X-ray scattering (GISAXS) at the silicon surface after the adsorption process. While SFM provides a topographical image of a small part of the adsorbed polyampholytic layer; GISAXS was used to get a statistical description of the lateral surface structures. The adsorbed structures were highly regular and their sizes were nearly pH independent over a lar ge pH region. Only directly at the isoelectric point of the polyampholyte larger adsorbed structures were observed. Compared with earlier investigated PMAA-b-PDMAEMA systems we are now able to prepare highly regular polyampholytic structures at silicon surfaces. There are two kinds of interactions for the adsorbed micelles. First, the charged block of the chains is directly attracted to the substrate via electrostatic interactions, while the uncharged part of the chains is only hydrophobically attracted via the hydrophobic core of the adsorbed micelle.

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Section: Scanning Force Microscopymentioning

confidence: 99%

Highly Regular Polyampholytic Structures Adsorbed Directly from Solution

Mahltig

Müller‐Buschbaum

Wolkenhauer

et al. 2001

Journal of Colloid and Interface Science

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“…Grazing incidence x-ray scattering ͑GIXS͒ provides such information on parallel structures. [25][26][27][28] Due to the peculiar geometry of the experiment, it offers a dramatic enhancement of the signal coming from the probed interface, without significantly sensing the overlaying bulk of solution ͑which is accessible via more conventional x-ray scattering͒. 29 GIXS has gained a lot of interest in the past years since it enables to study interfacial structures in a noninvasive and nondestructive way.…”

Section: Introductionmentioning

confidence: 99%

Flow at interfaces: A new device for x-ray surface scattering investigations

Moulin

Roth²,

Müller‐Buschbaum

2008

Review of Scientific Instruments

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A fluidic cell based setup is described which allows for microbeam grazing incidence small angle x-ray scattering characterization of the interface between a solid substrate and a flowing liquid. This cell can potentially be used to study in situ a wide variety of systems ranging from synthetic and natural colloids to biological molecules. The selected channel geometry enables the characterization of the solid-liquid interface during mixing of different solutions. As a proof of concept, measurements on an aqueous gold nanoparticle solution in contact with a glass surface are presented that show that the structure at the interface can be probed during flow.

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“…However, when the polymer films are annealed at temperatures higher than their T g or T m , the films may become unstable and dewetting takes place. [3][4][5] Depending on the substrate and the medium surrounding the layer, the wetting phase can form a continuous film, a single droplet or a pattern of discontinuous droplets. 6 If the interactions between substrate and polymer are van der Waals type, the values of the Hammaker constant A for polymer/polymer and polymer/substrate indicate the film stability.…”

Section: Introductionmentioning

confidence: 99%

“…If Apolymer/polymer is higher than Apolymer/substrate, dewetting will be favored. [3][4][5] This work is concerned with the morphology of thin polymer films obtained from spin-coating when different solvents are used. The interactions between substrate, polymer and solvent were qualitatively correlated with ) and poly(vinyl butyral), PVB, (M w 4 0.000 g mol -1 ) were kindly supplied by Trikem (São Paulo, Brazil) and Monsanto (São Paulo, Brazil), respectively.…”

Section: Introductionmentioning

confidence: 99%

Characterization of Spin-Coated Polymer Films

Petri¹

2002

J. Braz. Chem. Soc.

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Neste trabalho a morfologia de filmes obtidos por revestimento rotacional foi explicada como sendo resultante de forças competitivas entre polímero, solvente e substrato. Lâminas de silício (superfícies polares) suportaram os filmes. Tolueno e tetrahidrofurano (THF) foram os solventes escolhidos para dissolver poliestireno (PS), poli(cloreto de vinila) (PVC) e poli(butiral vinílico) (PVB). Análises de microscopia de força atômica mostraram que filmes de PS obtidos a partir de soluções preparadas em tolueno são homogêneos e lisos, enquanto filmes de PS e PVC obtidos a partir de soluções preparadas em THF são muito rugosos e segregados. Entretanto, filmes de PVB preparados a partir de soluções em THF são contínuos e homogêneos. Quando as interações entre substrato e solvente são mais favoráveis que as interações entre substrato e polímero, o filme se torna rugoso e segrega. Contrariamente, quando as interações entre substrato e polímero são mais favoráveis que as interações entre substrato e solvente, ou quando as interações são muito fracas, os filmes obtidos são homogêneos e lisos. Os filmes homogêneos e lisos também foram caracterizados por elipsometria e medidas de ângulo de contato.In this work the morphology of spin-coated polymer films is explained based on the competitive interactions between polymer, solvent and substrate. The films were formed on silicon wafers, a polar surface. Toluene and tetrahydrofuran (THF) were chosen for the dissolution of polystyrene (PS), poly(vinyl chloride) (PVC) and poly(vinyl butyral) (PVB). PS spin-coated films from solutions prepared in toluene were homogeneous and flat, while PS and PVC films obtained from solutions prepared in THF were very rough and presented segregation on the surface, as revealed by the atomic force microscopy. However, PVB films prepared from THF are continuous and homogeneous. When the interaction energy between substrate and solvent overcomes that between substrate and polymer, the films become rough and segregate. On the contrary, when the interaction energy between substrate and polymer is stronger than that between substrate and solvent, or when both interaction energies are weak, the films obtained are homogeneous and flat. These homogeneous and flat films were also characterized by ellipsometry and contact angle measurements.

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Observation of nano-dewetting structures

Cited by 88 publications

References 19 publications

Highly Regular Polyampholytic Structures Adsorbed Directly from Solution

Highly Regular Polyampholytic Structures Adsorbed Directly from Solution

Flow at interfaces: A new device for x-ray surface scattering investigations

Characterization of Spin-Coated Polymer Films

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