Nanothermoforming of hierarchical optical components utilizing shape memory polymers as active molds

Schneider, Norbert; Zeiger, Claudia; Kolew, Alexander; Schneider, Marc; Leuthold, Juerg; Hölscher, Hendrik; Worgull, Matthias

doi:10.1364/ome.4.001895

Cited by 14 publications

(14 citation statements)

References 27 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…SMP coatings that change both topography and color are appealing for a range of reconfigurable nanophotonic devices for optical data storage, photovoltaics, and optical sensors, as well as smart adhesives, biosurfaces, and battery‐free optical time‐analyte indicators . Regular surface topographies exhibiting structural colors have been fabricated in SMPs by top‐down methods including locally induced surface wrinkling, nanoimprint lithography, compression molding, or templating via microspheres . In these examples, hot pressing of the surface features results in a temporary flattened and colorless state, which is reversible upon heating …”

Section: Introductionmentioning

confidence: 99%

Photonic Shape Memory Chiral Nematic Polymer Coatings with Changing Surface Topography and Color

Nickmans

Heijden

Schenning

2019

Advanced Optical Materials

View full text Add to dashboard Cite

optical time-analyte indicators. [21,22] Regular surface topographies exhibiting structural colors have been fabricated in SMPs by top-down methods including locally induced surface wrinkling, [23] nanoimprint lithography, [24,25] compression molding, [26] or templating via microspheres. [27] In these examples, hot pressing of the surface features results in a temporary flattened and colorless state, which is reversible upon heating. [24][25][26][27] To circumvent the cumbersome topdown nanoforming steps to generate the structural color, photonic SMP coatings generated by bottom-up self-assembly have also been employed. [17,28,29] For example, shape memory photonic films have been produced from core-interlayer-shell polymer microspheres that form opal structures. [30][31][32] Alternatively porous inverse-opal SMPs have been templated by silica colloids. [33] Capillary pressure-induced "cold" programming of these materials results in a disordered temporary state consisting of collapsed pores and an arbitrarily roughened surface, which can be recovered by pressure, heat, organic vapors, solvents, and microwave radiation. [34][35][36][37][38][39] Unfortunately, the fabrication of such SMP coatings is still hampered by the lack of facile methods and materials. [40] Reactive liquid crystalline materials are exciting from this perspective since they form nanostructured phases via selfassembly, and can be easily processed via photopolymerization [41][42][43][44] to fabricate polymeric coatings. [45][46][47][48][49] Chiral nematic liquid crystalline (a.k.a. cholesteric liquid crystalline (CLC)) phases are of particular interest for their periodic helical structures which lead to the selective and incident-angledependent reflection of light, resulting in iridescent structural colors. [50] CLC coatings have been reported that respond to stimuli including heat, light, and humidity. [17,[51][52][53][54][55][56][57] In addition, CLC coatings have been reported that simultaneously change surface topography and color in a reversible manner. [41,55] Recently, our group reported that irreversible thermoresponsive photonic coatings can be fabricated based on CLC polymer networks using a shape memory approach. [58,59] Indentation of a small area (≈1 mm 2 ) of the CLC film, at a temperature above the T g of the polymer network, resulted in a blue-shift of the reflection band through a reduction of the pitch of the cholesteric helix, which was fully recovered upon heating.We now report a new approach for the fabrication of shape memory photonic coatings that irreversibly change both topography and color. Polymeric CLC films with a red structural The fabrication of shape memory coatings that change both reflectivity and topography is hampered by the lack of facile methods and materials. Now, shape memory photonic coatings are fabricated by high-speed flexographic printing and UV-curing in air of a chiral nematic liquid crystal ink. Deformable polymeric films with a red reflection band and a smooth surface topography are obtained which...

show abstract

Section: Introductionmentioning

confidence: 99%

Photonic Shape Memory Chiral Nematic Polymer Coatings with Changing Surface Topography and Color

Nickmans

Heijden

Schenning

2019

Advanced Optical Materials

View full text Add to dashboard Cite

show abstract

“…Those polymers were already exten- sively studied for macroscopic applications, e.g., for deployable components in aerospace [7], medical applications like self-unfolding stents, [8] or shape-memory sutures [1]. However, there are several applications where micro-or nano-structured active polymer devices are advantageous [9][10][11], e.g., as tunable nanostructured resonator substrates for optical devices.…”

Section: Introductionmentioning

confidence: 99%

Shape-memory polymers as flexible resonator substrates for continuously tunable organic DFB lasers

Schauer

Liu

Worgull

et al. 2015

Opt. Mater. Express

Self Cite

View full text Add to dashboard Cite

Abstract:We introduce shape-memory polymers (SMP) as substrate material for active optical devices. As an exemplary application we build a tunable organic semiconductor distributed feedback (DFB) laser. Hence, we transfer a second order Bragg grating with a period of 400 nm into SMP foils by hot embossing. The composite organic gain medium Alq 3 :DCM evaporated on the SMP substrate serves as laser active material. Mechanical stretching of the substrate increases the grating period temporarily and triggering the shape-memory effect afterwards reduces the period on demand. In this way, we can adjust the grating period to achieve a broad continuously tuning of the laser emission wavelength by 30 nm.

show abstract

“…Recently, a range of techniques for creating synthetic structurally colored systems have been reported in the literature. The methods each utilize a very different production technique, ranging from self-assembly [1][2][3][4] to deposition, growth, embossing, and etching techniques [5][6][7][8][9][10][11][12][13][14]. The nanofabrication methods are often highly inventive with different limitations on geometries and materials and, thus, also on obtainable colors and angle dependence.…”

Section: Introductionmentioning

confidence: 99%

“…The nanofabrication methods are often highly inventive with different limitations on geometries and materials and, thus, also on obtainable colors and angle dependence. The governing effects for color control are (layered) interference effects possibly combined with randomization [1,5,[7][8][9]11,12,14], structural (particle) scattering [2][3][4]6], and surface plasmon effects [10,13]. The approaches mentioned-which by no means provide an exhaustive list-all have their limitations due to manufacturability, such as good color selectivity but little control of angular reflection, or expensive fabrication and/or design procedures.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Designing visual appearance using a structured surface

Johansen¹,

Thamdrup²,

Smistrup³

et al. 2015

Optica

View full text Add to dashboard Cite

We present an approach for designing nanostructured surfaces with prescribed visual appearances, starting at design analysis and ending with a fabricated sample. The method is applied to a silicon wafer structured using deep ultraviolet lithography and dry etching and includes preliminary design followed by numerical and experimental verification. The approach comprises verifying all design and fabrication steps required to produce a desired appearance. We expect that the procedure in the future will yield structurally colored surfaces with appealing prescribed visual appearances.

show abstract

Nanothermoforming of hierarchical optical components utilizing shape memory polymers as active molds

Cited by 14 publications

References 27 publications

Photonic Shape Memory Chiral Nematic Polymer Coatings with Changing Surface Topography and Color

Photonic Shape Memory Chiral Nematic Polymer Coatings with Changing Surface Topography and Color

Shape-memory polymers as flexible resonator substrates for continuously tunable organic DFB lasers

Designing visual appearance using a structured surface

Contact Info

Product

Resources

About