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Title: The Self-Assembled Nanophase Particle (SNAP) Process: A Nanoscience Approach to Coatings

Abstract

In the corrosion protection of aluminum-skinned aircraft, surface pretreatment and cleaning are critical steps in protecting aerospace alloys from corrosion. Our recent discovery of a revolutionary new method of forming functionalized silica nanoparticles in situ in an aqueous-based sol-gel process, and then crosslinking the nanoparticles to form a thin film, is an excellent example of a nanoscience approach to coatings. This coating method is called the self-assembled nanophase particle (SNAP) process. The SNAP coating process consists of three stages: (1) sol-gel processing; (2) SNAP solution mixing; (3) SNAP coating application and cure. Here, we report on key parameters in the ''sol-gel processing'' and the ''coating application and cure'' stages in the GPTMS/TMOS system. The SNAP process is discussed from the formation of the nanosized macromolecules to the coating application and curing process. The ''sol-gel processing'' stage involves hydrolysis and condensation reactions and is controlled by the solution pH and water content. Here, the molar ratio of water to hydrolysable silane is a key factor. SNAP solutions have been investigated by NMR, IR, light scattering, and GPC to identify molecular condensation structures formed as a function of aging time in the solution. In moderate pH and highwater content solutions, hydrolysis occursmore » rapidly and condensation kinetic conditions are optimized to generate nanophase siloxane macromolecules. In the ''SNAP solution mixing'' stage, crosslinking agents and additives are added to the solution, which is then applied to a substrate by dip-coating to form the SNAP coating. The chemical structure and morphology of the films have been characterized using X-ray diffraction (XRD), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and atomic force microscopy (AFM). SNAP films are amorphous but exhibit nanostructured assembly of siloxane oligomers at a separation of about 1.8 nm as well as molecular level ordering of O-Si-O species. The surface analytical data indicate that the films retain the basic chemical arrangement of the siloxane macromolecules/oligomers and crosslinking process creates a network of siloxane oligomers tethered together. Results of these analyses are then used to construct a model of the SNAP coating.« less

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Pacific Northwest National Laboratory (PNNL), Richland, WA (US), Environmental Molecular Sciences Laboratory (EMSL)
Sponsoring Org.:
USDOE
OSTI Identifier:
15010518
Report Number(s):
PNNL-SA-40538
2210; 2357; 3021; KP1301030
DOE Contract Number:  
AC05-76RL01830
Resource Type:
Journal Article
Journal Name:
Progress in Organic Coatings, 47(3-4):401-415
Additional Journal Information:
Journal Name: Progress in Organic Coatings, 47(3-4):401-415
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; environmental molecular sciences laboratory; SNAP, time-of-flight secondary ion mass spectrometry, atomic force microscopy, nanophase, self-assembly, XPS

Citation Formats

Donley, Michael S, Mantz, Robert A, Khramov, A N, Balbyshev, Vsevolod, Kasten, Linda S, and Gaspar, Dan J. The Self-Assembled Nanophase Particle (SNAP) Process: A Nanoscience Approach to Coatings. United States: N. p., 2003. Web. doi:10.1016/j.porgcoat.2003.08.017.
Donley, Michael S, Mantz, Robert A, Khramov, A N, Balbyshev, Vsevolod, Kasten, Linda S, & Gaspar, Dan J. The Self-Assembled Nanophase Particle (SNAP) Process: A Nanoscience Approach to Coatings. United States. doi:10.1016/j.porgcoat.2003.08.017.
Donley, Michael S, Mantz, Robert A, Khramov, A N, Balbyshev, Vsevolod, Kasten, Linda S, and Gaspar, Dan J. Mon . "The Self-Assembled Nanophase Particle (SNAP) Process: A Nanoscience Approach to Coatings". United States. doi:10.1016/j.porgcoat.2003.08.017.
@article{osti_15010518,
title = {The Self-Assembled Nanophase Particle (SNAP) Process: A Nanoscience Approach to Coatings},
author = {Donley, Michael S and Mantz, Robert A and Khramov, A N and Balbyshev, Vsevolod and Kasten, Linda S and Gaspar, Dan J},
abstractNote = {In the corrosion protection of aluminum-skinned aircraft, surface pretreatment and cleaning are critical steps in protecting aerospace alloys from corrosion. Our recent discovery of a revolutionary new method of forming functionalized silica nanoparticles in situ in an aqueous-based sol-gel process, and then crosslinking the nanoparticles to form a thin film, is an excellent example of a nanoscience approach to coatings. This coating method is called the self-assembled nanophase particle (SNAP) process. The SNAP coating process consists of three stages: (1) sol-gel processing; (2) SNAP solution mixing; (3) SNAP coating application and cure. Here, we report on key parameters in the ''sol-gel processing'' and the ''coating application and cure'' stages in the GPTMS/TMOS system. The SNAP process is discussed from the formation of the nanosized macromolecules to the coating application and curing process. The ''sol-gel processing'' stage involves hydrolysis and condensation reactions and is controlled by the solution pH and water content. Here, the molar ratio of water to hydrolysable silane is a key factor. SNAP solutions have been investigated by NMR, IR, light scattering, and GPC to identify molecular condensation structures formed as a function of aging time in the solution. In moderate pH and highwater content solutions, hydrolysis occurs rapidly and condensation kinetic conditions are optimized to generate nanophase siloxane macromolecules. In the ''SNAP solution mixing'' stage, crosslinking agents and additives are added to the solution, which is then applied to a substrate by dip-coating to form the SNAP coating. The chemical structure and morphology of the films have been characterized using X-ray diffraction (XRD), time-of-flight secondary ion mass spectrometry (TOF-SIMS) and atomic force microscopy (AFM). SNAP films are amorphous but exhibit nanostructured assembly of siloxane oligomers at a separation of about 1.8 nm as well as molecular level ordering of O-Si-O species. The surface analytical data indicate that the films retain the basic chemical arrangement of the siloxane macromolecules/oligomers and crosslinking process creates a network of siloxane oligomers tethered together. Results of these analyses are then used to construct a model of the SNAP coating.},
doi = {10.1016/j.porgcoat.2003.08.017},
journal = {Progress in Organic Coatings, 47(3-4):401-415},
number = ,
volume = ,
place = {United States},
year = {2003},
month = {9}
}