Method to suppress period doubling during manufacture of micro and nano scale wrinkled structures
OwnerSourabh Kumar Sahainventor
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Abstract
The range of stretch-tunability of sinusoidal wrinkled surfaces that are obtained by compression of supported thin films is limited by the emergence of a period-doubled mode at high compressive strains. This disclosure presents a method to suppress the emergence of the period-doubled mode at high strains. This is achieved by compressing pre-patterned supported thin films, wherein the pre-patterns are substantially similar to the natural pattern of the supported thin film system. As compared to flat thin film systems, pre-patterned thin film systems exhibit period doubling behavior at a higher compressive strain. The onset strain for emergence of period-doubling is tuned by altering the amplitude of the pre-patterns.
Claims19
A method of suppressing a phenomenon of period doubling at high strains during wrinkling of bilayers, comprising the steps of:
- providing a topographically patterned surface, wherein the topographic pattern is a sinusoidal periodic pattern and has a period that is substantially similar to the natural period of the bilayer;
- replicating the patterned surface onto a base substrate, thereby forming a non-flat pre-patterned surface on the base;
- stretching the pre-patterned base substrate beyond the nominal period doubling onset strain, thereby forming a stretched and pre-patterned base layer;
- generating a thin film on top of the stretched pre-patterned base layer, wherein the film conforms to the pre-patterned surface, thereby forming a composite pre-patterned material comprising a thin film on top of a stretched and pre-patterned base layer;
- releasing the strain in the stretched pre-patterned base layer of the composite material, wherein releasing the strain by an amount smaller than or larger than the nominal period doubling onset strain leads to an increase in an amplitude of the pre-patterns without emergence of a period doubled mode, thereby suppressing the phenomenon of period doubling at high strains during wrinkling.
A method of suppressing a phenomenon of period doubling at high strains during wrinkling of bilayers, comprising the steps of:
- providing a topographically patterned surface, wherein the topographic pattern is a sinusoidal periodic pattern and has a period that is substantially similar to the natural period of the bilayer;
- replicating the patterned surface onto a base substrate, thereby forming a non-flat pre-patterned surface on the base;
- stretching the pre-patterned base substrate along two different directions, wherein one stretch direction is aligned along a direction of periodicity of the pre-patterned surface, and wherein the strain along this aligned direction is higher than the nominal period doubling onset strain, thereby forming a stretched and pre-patterned base layer;
- generating a thin film on top of the stretched pre-patterned base layer, wherein the film conforms to the pre-patterned surface, thereby forming a composite pre-patterned material comprising a thin film on top of a stretched and pre-patterned base layer;
- releasing the strain along the aligned direction, wherein releasing the strain leads to an increase in an amplitude of the pre-patterns without emergence of a period doubled mode, thereby forming a high aspect ratio wrinkled surface with the same period as that of the pre-pattern;
- subsequently releasing the strain along the second direction, wherein releasing the strain leads to the thin film to buckle along the second direction, thereby forming a high aspect ratio biaxially wrinkled surface.
A method of suppressing a phenomenon of period doubling at high strains during wrinkling of bilayers, comprising the steps of:
- providing a topographically patterned surface, wherein the topographic pattern is a sinusoidal periodic pattern and has a period that is substantially similar to the natural period of the bilayer;
- replicating the patterned surface onto a base substrate, thereby forming a non-flat pre-patterned surface on the base;
- stretching the pre-patterned base substrate along two different directions, wherein one stretch direction is aligned along a direction of periodicity of the pre-patterned surface, and wherein the strain along this aligned direction is higher than the nominal period doubling onset strain, thereby forming a stretched and pre-patterned base layer;
- generating a thin film on top of the stretched pre-patterned base layer, wherein the film conforms to the pre-patterned surface, thereby forming a composite pre-patterned material comprising a thin film on top of a stretched and pre-patterned base layer;
- simultaneously releasing the strain along both the directions, wherein releasing the strain leads to the thin film to buckle along both the directions, and wherein releasing the strain leads to an increase in an amplitude of the pre-patterns along one direction without emergence of a period doubled mode, thereby forming a high aspect ratio biaxially wrinkled surface.
Dependencies are inferred from the claim text.