Spacious and mechanically flexible mesoporous silica thin film composed of an open network of interlinked nanoslabs

Abstract

Transparent and smooth silica thin films with a very high porosity were prepared by linking zeolitic nanoslabs into open mesoporous networks. Calcined films characterized by ellipsometric porosimetry presented pore sizes in the range of 6-18 nm and porosities of 70-90% depending on the temperature of assembly of the nanoslabs in the presence of Pluronic P123 triblock copolymer. The films were disordered according to grazing incidence small angle X-ray scattering and transmission electron microscopy. The most spacious film had a very low refractive index of 1.08 (at 632.8 nm) and exhibited reversible shrinkage of up to 30% of its original thickness upon capillary condensation of adsorbate vapor. The mechanical flexibility of the film was confirmed by the low Young modulus of 0.9 GPa determined by nano-indentation. The full accessibility of the porosity and the convenience for chemical functionalization were demonstrated using Atomic Layer Deposition (ALD) of TiO 2 monitored with Rutherford Backscattering Spectroscopy. Using ALD the porosity and mechanical flexibility of the film could be fine tuned.

Plasma enhanced atomic layer deposition of Ga2O3thin films

“…66 Ellipsometric porosimetry measurements showed that the silica lm had a thickness of 150 nm, a porosity of 55% and a surface area of ca. large area nanostructured substrates for sensing or catalytic applications, the conformal nature of the novel PE-ALD process was veried.…”

Fabrication of Macroscopically Flexible and Highly Porous 3D Semiconductor Networks from Interpenetrating Nanostructures by a Simple Flame Transport Approach

“…Flexibility is a desired property for all the materials dealing with expansion due to heat, swelling due to lithium uptake, or bendable electronics, however it is specific for organic materials. A material can be classified as mechanically flexible if it exhibits a Young's modulus value below 1 GPa . In general, ceramic materials or classical semiconductors are typically rigid and brittle.…”

Synchrotron based in situ characterization during atomic layer deposition

“…While the possibility for tailoring the pore size and the composition of the pore wall opens excltmg opportunities in the fields of catalysis and molecular filtration, the penetration of ALD layers inside nanoporous low-k materials is typically perceived as a disadvantage within the micro-electronics community. In our recent work [4][5][6][7][8][9][10], in-situ XRF was used to quantify the penetration of ALD in nanoporous thin films. In [10], nanoporous SiCOH low-k films with a porosity of � 45% and interconnected pores with a diameters of � 3 nm.…”