Sealed ultra low-k organosilica films with improved electrical, mechanical and chemical properties

Goethals, Frederik; Levrau, Elisabeth; Pollefeyt, Glenn; Baklanov, Mikhaı̈l R.; Ciofi, Ivan; Vanstreels, Kris; Detavernier, Christophe; Driessche, Isabel Van; Voort, Pascal Van Der

doi:10.1039/c3tc30522h

Cited by 7 publications

(4 citation statements)

References 27 publications

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“…1 The ethylene bridge tends to enhance the average micropore size as compared to pure silica, [3][4][5][6] but despite the addition of hydrophobic organic segments the material keeps on having a signicant affinity for water. [6][7][8][9][10] Ethylene-bridged organosilica in mesoporous architectures is particularly interesting as low-k material, 1,11 is UV-responsive upon metal doping 12 and has been used in chiral thermochromic composites. 13 An important application of microporous BTESE-based organosilica is in molecular sieving membranes, [14][15][16] which are being employed industrially.…”

Section: Introductionmentioning

confidence: 99%

Long-term flexibility-based structural evolution and condensation in microporous organosilica membranes for gas separation

et al. 2017

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Section: Introductionmentioning

confidence: 99%

Long-term flexibility-based structural evolution and condensation in microporous organosilica membranes for gas separation

et al. 2017

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“…In general, carbon‐bridged organosilicas have low intrinsic dielectric constants and higher Young's moduli than terminal‐methyl organosilicas . PMOs derived specifically from HETSCH and related molecules have been explored as low‐ k dielectric interlayers . Notably, only cylindrical pore HETSCH PMOs have been reported to date.…”

Section: Resultsmentioning

confidence: 99%

“…Notably, only cylindrical pore HETSCH PMOs have been reported to date. Nonetheless, porosities up to 55% have been reported for these anisotropic PMOs, whose dielectric constants were reported as low as 1.8 for HETSCH and 1.6 for methylene‐bridged compounds . Higher porosities would be required to lower those values any further, if desirable.…”

Section: Resultsmentioning

confidence: 99%

Block Copolymer Packing Limits and Interfacial Reconfigurability in the Assembly of Periodic Mesoporous Organosilicas

Wills

Michalak

Ercius

et al. 2015

Adv Funct Materials

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wileyonlinelibrary.comwith mesoscale dimensions are of particular interest; they can be introduced by embedding molecular or polymeric porogens within the host material and then processing the composite to create mesopores. [17][18][19][20][21][22][23][24][25][26][27][28] Elucidating design rules for how mesopore dimensions, shape, spatial arrangement, and defect structure dictate properties relies on access to well-controlled, ordered architectures for a wider range of overall porosity than has been possible previously. [ 5,23,29,30 ] To advance the science of mesoscale assembly, a careful revaluation of the factors governing porogen packing and shape persistence before and after processing is needed.We describe here a robust framework to understand the fundamental packing limits for spherical block copoly mer (BCP) micellar porogens during the assembly and thermal processing of periodic mesoporous organosilicas (PMOs), shown schematically in Figure 1 . For this work, we developed and applied a new family of block copolymer (BCP) architecture-directing agents based on a poly(styrene)-blockpoly( N,N-dimethylacrylamide) (PS-b -PDMA) platform. [ 31,32 ] Under the acidic conditions used to hydrolyze 1,1,3,3,5,5-hexaethoxy-1,3,5-trisilacyclohexane (HETSCH), our PMO matrix precursor, we show that the HCl ( aq ) adsorbs to the corona of the PS-b -PDMA micelles. The electrostatic interactions that result, both between micelles, and with hydrolyzed HETSCH molecules, effi ciently direct the periodic arrangements of porogens in the composite fi lms for total porogen volume fractions spanning 26%-78%. A simple spin-on procedure was able to produce uniform fi lms with tunable thicknesses between 50 and 1000 nm across 5 cm × 5 cm Si substrates, and controlled thermal processing yielded structurally sound PMOs for all fi lms. Our implementation of PS-b -PDMA BCPs as PMO architecture-directing agents allows us to independently defi ne a specifi c pore size and shape across a wide range of porosities. As such, we can provide here a more comprehensive portrait into the nonequilibrium structures and phenomena yielding PMOs than has been possible previously. [33][34][35][36][37] One notable and unexpected outcome of our work includes the observation that the degree of order as determined by ( N,N -dimethylacrylamide)-block -poly(styrene) block copolymer micelles (BCPs) are advanced and applied to assemble periodic mesoporous organosilicas (PMOs) with noncylindrical pores. Using these BCP micelles, it is found that pore dimensions (11-23 nm), wall thicknesses (5-9 nm), and overall porosities (26%-78%) are independently programable, depending only on relative inputs for BCP and matrix former. Notably, the degree of order in all fi lms improves as BCP loading approaches a packing limit of 63 vol%. Beyond this limit and regardless of pore dimensions, both porogen packing in the fi lm and pore structure after thermal processing show signifi cant deviations away from spherical close-packed lattices. The surprising absence of fi lm colla...

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“…The position of the organic groups can be terminal (Si–R) or bridging (Si–R’–Si), which affects their exposure at the (internal) surface and influences the crosslink density and microporosity of the network [ 3 ]. Organosilicas can be prepared by mild and versatile sol-gel routes and applications are, for instance, molecular separation membranes [ 4 ], catalysts [ 5 ], low-k materials [ 6 , 7 ] and sensors [ 8 ]. Organosilica networks offer the combined advantage of a mechanically strong yet flexible network.…”

Section: Introductionmentioning

confidence: 99%

Thermochemical Stability and Friction Properties of Soft Organosilica Networks for Solid Lubrication

et al. 2018

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In view of their possible application as high temperature solid lubricants, the tribological and thermochemical properties of several organosilica networks were investigated over a range of temperatures between 25 and 580 °C. Organosilica networks, obtained from monomers with terminal and bridging organic groups, were synthesized by a sol-gel process. The influence of carbon content, crosslink density, rotational freedom of incorporated hydrocarbon groups, and network connectivity on the high temperature friction properties of the polymer was studied for condensed materials from silicon alkoxide precursors with terminating organic groups, i.e., methyltrimethoxysilane, propyltrimethoxysilane, diisopropyldimethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane and 4-biphenylyltriethoxysilane networks, as well as precursors with organic bridging groups between Si centers, i.e., 1,4-bis(triethoxysilyl)benzene and 4,4′-bis(triethoxysilyl)-1,1′-biphenyl. Pin-on-disc measurements were performed using all selected solid lubricants. It was found that materials obtained from phenyltrimethoxysilane and cyclohexyltrimethoxysilane precursors showed softening above 120 °C and performed best in terms of friction reduction, reaching friction coefficients as low as 0.01. This value is lower than that of graphite films (0.050 ± 0.005), a common bench mark for solid lubricants.

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Sealed ultra low-k organosilica films with improved electrical, mechanical and chemical properties

Cited by 7 publications

References 27 publications

Long-term flexibility-based structural evolution and condensation in microporous organosilica membranes for gas separation

Long-term flexibility-based structural evolution and condensation in microporous organosilica membranes for gas separation

Block Copolymer Packing Limits and Interfacial Reconfigurability in the Assembly of Periodic Mesoporous Organosilicas

Thermochemical Stability and Friction Properties of Soft Organosilica Networks for Solid Lubrication

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