• Study Resource
  • Explore Categories
    • Arts & Humanities
    • Business
    • Engineering & Technology
    • Foreign Language
    • History
    • Math
    • Science
    • Social Science

    Top subcategories

    • Advanced Math
    • Algebra
    • Basic Math
    • Calculus
    • Geometry
    • Linear Algebra
    • Pre-Algebra
    • Pre-Calculus
    • Statistics And Probability
    • Trigonometry
    • other →

    Top subcategories

    • Astronomy
    • Astrophysics
    • Biology
    • Chemistry
    • Earth Science
    • Environmental Science
    • Health Science
    • Physics
    • other →

    Top subcategories

    • Anthropology
    • Law
    • Political Science
    • Psychology
    • Sociology
    • other →

    Top subcategories

    • Accounting
    • Economics
    • Finance
    • Management
    • other →

    Top subcategories

    • Aerospace Engineering
    • Bioengineering
    • Chemical Engineering
    • Civil Engineering
    • Computer Science
    • Electrical Engineering
    • Industrial Engineering
    • Mechanical Engineering
    • Web Design
    • other →

    Top subcategories

    • Architecture
    • Communications
    • English
    • Gender Studies
    • Music
    • Performing Arts
    • Philosophy
    • Religious Studies
    • Writing
    • other →

    Top subcategories

    • Ancient History
    • European History
    • US History
    • World History
    • other →

    Top subcategories

    • Croatian
    • Czech
    • Finnish
    • Greek
    • Hindi
    • Japanese
    • Korean
    • Persian
    • Swedish
    • Turkish
    • other →
 
Profile Documents Logout
Upload
5. GÖCH Symposium 2016 “Physikalische Chemie in Österreich”
5. GÖCH Symposium 2016 “Physikalische Chemie in Österreich”

2013 us national chemistry olympiad
2013 us national chemistry olympiad

Plastic nanocomposite insulation material enabling reliable
Plastic nanocomposite insulation material enabling reliable

... surface functionalization of the filler. Chemical methods involve the use of coupling agents (e.g. alkylsilanes, polysiloxanes or polymeric coupling agents) or by grafting polymers. Furthermore, both treatment can be combined. The novel filler technology with chemical and / or physical modifications ...
Roughness analysis of the
Roughness analysis of the

Stylolite formation process: Surface Roughness
Stylolite formation process: Surface Roughness

Week 10 Day 2-Plastics - Washington State University
Week 10 Day 2-Plastics - Washington State University

Self-Assembly Structures of Nonionic Surfactants at Graphite
Self-Assembly Structures of Nonionic Surfactants at Graphite

Syntheses of Soluble, -Stacking Tetracene Derivatives π
Syntheses of Soluble, -Stacking Tetracene Derivatives π

MEMS Processing
MEMS Processing

... Basic MEMS materials Silicon and its derivatives, mostly • Micro-electronics heritage Si is a good semiconductor, properties can be tuned Si oxide is very robust Si nitride is a good electrical insulator ...
THE CREATION OF EXPLOSIVE CONTAMINATION STANDARDS:
THE CREATION OF EXPLOSIVE CONTAMINATION STANDARDS:

SIDE GROUP ADDITION TO THE POLYCYCLIC AROMATIC
SIDE GROUP ADDITION TO THE POLYCYCLIC AROMATIC

Adsorption of Phenol and 4-Hydroxybenzoic Acid onto Functional
Adsorption of Phenol and 4-Hydroxybenzoic Acid onto Functional

Molecular Modeling Activity for Carbohydrates
Molecular Modeling Activity for Carbohydrates

AP CHEMISTRY – Source: 1999 AP Exam CHAPTER 8 TEST
AP CHEMISTRY – Source: 1999 AP Exam CHAPTER 8 TEST

Slides - Jung Y. Huang
Slides - Jung Y. Huang

Project-BR
Project-BR

SCHLOSS RINGBERG
SCHLOSS RINGBERG

downey_poster - SURF-IT Summer Research
downey_poster - SURF-IT Summer Research

Characterization techniques for nanotechnology
Characterization techniques for nanotechnology

... scattered electrons and characteristic X-rays are generated that contain information about the sample's surface topography, composition, etc. The SEM can produce very high-resolution images of a sample surface, revealing details about 1-5 nm in size in its primary detection mode i.e. secondary elect ...
Joint Symposium of Waseda University and Peking University
Joint Symposium of Waseda University and Peking University

Chapter 13: Properties of Solutions
Chapter 13: Properties of Solutions

(NH4)2S surface passivation
(NH4)2S surface passivation

dmi cleaning and maintenance
dmi cleaning and maintenance

... periodic cleaning to remove build-ups of resins and other residue is a good idea to extend coating life. Simple washing with plain water using hoses or pressure spray equipment is usually adequate. When heavy deposits of dirt or other contaminants dull surfaces, a heavy-duty dry powdered laundry det ...
Enzymes: “Helper” Protein molecules
Enzymes: “Helper” Protein molecules

Preparation of Sm–Ru bimetallic alloy films on Ru(0001) surface by
Preparation of Sm–Ru bimetallic alloy films on Ru(0001) surface by

< 1 ... 13 14 15 16 17 18 19 20 21 ... 25 >

Self-assembled monolayer



Self-assembled monolayers (SAM) of organic molecules are molecular assemblies formed spontaneously on surfaces by adsorption and are organized into more or less large ordered domains. In some cases molecules that form the monolayer do not interact strongly with the substrate. This is the case for instance of the two-dimensional supramolecular networks of e.g. Perylene-tetracarboxylicacid-dianhydride (PTCDA) on gold or of e.g. porphyrins on highly oriented pyrolitic graphite (HOPG). In other cases the molecules possess a head group that has a strong affinity to the substrate and anchors the molecule to it. Such a SAM consisting of a head group, tail and functional end group is depicted in Figure 1. Common head groups include thiols, silanes, phosphonates, etc.SAMs are created by the chemisorption of ""head groups"" onto a substrate from either the vapor or liquid phase followed by a slow organization of ""tail groups"". Initially, at small molecular density on the surface, adsorbate molecules form either a disordered mass of molecules or form an ordered two-dimensional ""lying down phase"", and at higher molecular coverage, over a period of minutes to hours, begin to form three-dimensional crystalline or semicrystalline structures on the substrate surface. The ""head groups"" assemble together on the substrate, while the tail groups assemble far from the substrate. Areas of close-packed molecules nucleate and grow until the surface of the substrate is covered in a single monolayer.Adsorbate molecules adsorb readily because they lower the surface free-energy of the substrate and are stable due to the strong chemisorption of the ""head groups."" These bonds create monolayers that are more stable than the physisorbed bonds of Langmuir–Blodgett films. A Trichlorosilane based ""head group"", for example in a FDTS molecule reacts with an hydroxyl group on a substrate, and forms very stable, covalent bond [R-Si-O-substrate] with an energy of 452 kJ/mol. Thiol-metal bonds, that are on the order of 100 kJ/mol, making the bond a fairly stable in a variety of temperature, solvents, and potentials. The monolayer packs tightly due to van der Waals interactions, thereby reducing its own free energy. The adsorption can be described by the Langmuir adsorption isotherm if lateral interactions are neglected. If they cannot be neglected, the adsorption is better described by the Frumkin isotherm.
  • studyres.com © 2025
  • DMCA
  • Privacy
  • Terms
  • Report