Functional nanocomposites prepared by self-assembly and polymerization of diacetylene surfactants and silicic acid.
Conjugated polymer/silica nanocomposites with hexagonal, cubic, or lamellar mesoscopic order were synthesized by self-assembly using polymerizable amphiphilic diacetylene molecules as both structure-directing agents and monomers. The self-assembly procedure is rapid and incorporates the organic monomers uniformly within a highly ordered, inorganic environment. By tailoring the size of the oligo(ethylene glycol) headgroup of the diacetylene-containing surfactant, we varied the resulting self-assembled mesophases of the composite material. The nanostructured inorganic host altered the diacetylene polymerization behavior, and the resulting nanocomposites show unique thermo-, mechano-, and solvatochromic properties. Polymerization of the incorporated surfactants resulted in polydiacetylene (PDA)/silica nanocomposites that were optically transparent and mechanically robust. Molecular modeling and quantum calculations and (13)C spin-lattice relaxation times (T(1)) of the PDA/silica nanocomposites indicated that the surfactant monomers can be uniformly organized into precise spatial arrangements prior to polymerization. Nanoindentation and gas transport experiments showed that these nanocomposite films have increased hardness and reduced permeability as compared to pure PDA. Our work demonstrates polymerizable surfactant/silica self-assembly to be an efficient, general approach to the formation of nanostructured conjugated polymers. The nanostructured inorganic framework serves to protect, stabilize, and orient the polymer, mediate its performance, and provide sufficient mechanical and chemical stability to enable integration of conjugated polymers into devices and microsystems.
Yang
Yi
Y
Center for Micro-Engineered Materials, The University of New Mexico, Albuquerque, New Mexico 87131, USA.
Lu
Yunfeng
Y
Lu
Mengcheng
M
Huang
Jinman
J
Haddad
Raid
R
Xomeritakis
George
G
Liu
Nanguo
N
Malanoski
Anthony P
AP
Sturmayr
Dietmar
D
Fan
Hongyou
H
Sasaki
Darryl Y
DY
Assink
Roger A
RA
Shelnutt
John A
JA
van Swol
Frank
F
Lopez
Gabriel P
GP
Burns
Alan R
AR
Brinker
C Jeffrey
CJ
D000114:Acetylene / Q000031:analogs & derivatives* / Q000138:chemical synthesis* / Q000737:chemistry; D019245:Compressive Strength; D008422:Materials Testing; D008958:Models, Molecular; D009010:Monte Carlo Method; D036103:Nanotechnology; D000078789:Polyacetylene Polymer; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D053279:Polyynes; D011789:Quantum Theory; D012824:Silicic Acid / Q000737:chemistry*; D012997:Solvents; D013501:Surface-Active Agents / Q000737:chemistry*; D014466:Ultraviolet Rays; D014961:X-Ray Diffraction
D000078789:Polyacetylene Polymer; D011108:Polymers; D012997:Solvents; D013501:Surface-Active Agents; D012824:Silicic Acid; D053279:Polyynes; C082361:polydiacetylene; D000114:Acetylene