Fabrication of Multilayered Nanoporous Poly(methyl silsesquioxane)

Kim, Ho-Cheol; Wilds, Jason B.; Kreller, Cortney R.; Volksen, Willi; Brock, Phillip J.; Lee, Victor Y.; Magbitang, Teddie; Hedrick, James L.; Hawker, Craig J.; Miller, Robert D.

doi:10.1002/1521-4095(20021118)14:22<1637::aid-adma1637>3.0.co;2-c

Cited by 60 publications

(104 citation statements)

References 10 publications

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“…16 Nanoporous ormosil bulk materials and thin films can be prepared using selfassembling template molecules to form periodic nanopores 17 or by sacrificial polymers to induce nano-phase separation. 18 However, the additional removal step of sacrificial substances requires harsh conditions, i.e. high temperature (400-450 C) and/or low pH (<1), further complicating the process, and limiting the choice of substrate in the case of thin films.…”

Section: Introductionmentioning

confidence: 99%

Template free preparation of nanoporous organically modified silica thin films on flexible substrates

et al. 2011

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We report the preparation and characterization of nanoporous organically modified silica (ormosil) thin films at room temperature and neutral pH conditions from homogeneous methyl silsesquioxane (MSQ) gels. Universally applicable and stable colloidal ormosil suspensions are prepared from the gels by sonication and coated to the substrates including glass, paper and plastics. The nanoporosity and thickness of the films can be tuned, which makes them suitable for certain applications including sensing, functional coatings, and low-dielectric materials. We demonstrate the antireflection property of the films on glass, cellulose acetate (CA) and polyetherimide (PEI) substrates. The films on CA and PEI retain their antireflection property after multiple bending cycles. Furthermore, films are intrinsically hydrophobic, over a wide pH range, with static contact angles up to 143 on paper and 123 on glass and CA. Producing nanoporous ormosil thin films on flexible substrates may expand their use in low cost electronic, optical devices and sensors, and lab-on-paper applications.

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Section: Introductionmentioning

confidence: 99%

Template free preparation of nanoporous organically modified silica thin films on flexible substrates

et al. 2011

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“…A sacrificial-porogen technique based on the selective removal of the organic macromolecular porogen from phase-separated mixtures of organic/ inorganic nanohybrids used in this experiment was prepared and supplied by International Business Machines Corp. ͑IBM™͒ Almaden Research Center. 21 Two sets of these porous films with open-or closed-pore geometries were used. These films were fabricated by mixing appropriate ratios of porogen and matrix precursor; 25% by weight porogen loading for closed pore and 55% by weight porogen loading for open pore, respectively.…”

Section: Methodsmentioning

confidence: 99%

“…The details of bilayer sample preparation can be found elsewhere. 21 We also prepared another set of porous films by mixing 50% PPG ͑MW= 600 g / mol͒ and 50% PMSSQ. PGMEA was used as solvent for both PPG and PMSSQ solutions.…”

Section: Methodsmentioning

confidence: 99%

Characterization of porous low-k films using variable angle spectroscopic ellipsometry

Othman

Lubguban

et al. 2006

Journal of Applied Physics

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Variable angle spectroscopic ellipsometry ͑VASE™͒ is used as a tool to characterize properties such as optical constant, thickness, refractive index depth profile, and pore volume fraction of single and bilayer porous low-k films. The porous films were prepared using sacrificial pore generator ͑porogen͒ approach. Two sets of porous films with open-and closed-pore geometries were measured. Three models were used for data analysis: Cauchy, Bruggeman effective medium approximation ͑BEMA͒, and graded layer. Cauchy, a well-known model for transparent films, was used to obtain thickness and optical constant, whereas BEMA was utilized to calculate the pore volume fraction from the ellipsometric data. The Cauchy or BEMA models were then modified as graded layers, resulting in a better fit and a better understanding of the porous film. The depth profile of the porous film implied a more porous layer at the substrate-film interface. We found 3%-4% more porosity at the interface compared with the bulk for both films. This work shows that VASE™, a nondestructive measurement tool, can be used to characterize single-and multigraded layer porous films quickly and effectively.

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“…Such low refractive index films obtained by spin coating are unprecedented [28]. It is interesting to note that, even at sufficiently high porogen loadings (>80%), the refractive index of films reported using the sacrificial porogen approach is still comparatively high (∼1.13-1.18) [22,10]. In addition, due to the monolithic structure of these films, it is expected that the optical constants of these films (sacrificial porogen approach) remain constant as a function of calcination temperature provided complete porogen burn out occurs.…”

Section: Curing/calcination Temperature Dependent System Behaviormentioning

confidence: 99%

Entropy driven spontaneous formation of highly porous films from polymer–nanoparticle composites

Korampally¹,

Yun²,

Thiruvengadathan³

et al. 2009

Nanotechnology

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Nanoporous materials have become indispensable in many fields ranging from photonics, catalysis and semiconductor processing to biosensor infrastructure. Rapid and energy efficient process fabrication of these materials is, however, nontrivial. In this communication, we describe a simple method for the rapid fabrication of these materials from colloidal dispersions of Polymethyl Silsesquioxane nanoparticles. Nanoparticle-polymer composites above the decomposition temperature of the polymer are examined and the entropic gain experienced by the nanoparticles in this rubric is harnessed to fabricate novel highly porous films composed of nanoparticles. Optically smooth, hydrophobic films with low refractive indices (as low as 1.048) and high surface areas (as high as 1325 m 2 g −1 ) have been achieved with this approach. In this communication we address the behavior of such systems that are both temperature and substrate surface energy dependent. The method is applicable, in principle, to a variety of nanoparticle-polymer systems to fabricate custom nanoporous materials.

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Fabrication of Multilayered Nanoporous Poly(methyl silsesquioxane)

Cited by 60 publications

References 10 publications

Template free preparation of nanoporous organically modified silica thin films on flexible substrates

Template free preparation of nanoporous organically modified silica thin films on flexible substrates

Characterization of porous low-k films using variable angle spectroscopic ellipsometry

Entropy driven spontaneous formation of highly porous films from polymer–nanoparticle composites

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