Modeling of azopolymer surface restructuring under complex irradiation patterns

复杂辐照模式下偶氮聚合物表面重构的建模

• 批准号: 526190489
• 负责人: Privatdozentin Dr. Marina Grenzer
• 金额: --
• 依托单位: Leibniz-Institut für Polymerforschung Dresden (IPF)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 资助国家: 德国
• 项目状态: 未结题
• 来源: https://gepris.dfg.de/gepris/projekt/526190489?language=en
• 关键词: Modeling; azopolymer; surface; restructuring; under

Polymers that can change their molecular architecture under such an external stimulus as light have attracted great attention in the scientific community. Particularly known are photosensitive azopolymers, which have many applications in different fields due to their high versatility. In modern engineering, a special interest has been evoked by a unique opportunity to control the deformations of thin azopolymer films depending on the light irradiation pattern. The topographical restructuring has been used to produce the surfaces with light-controlled wettability, templates for living cells in biotechnology, large-scale multiplexed gratings for photonic applications. Multiple theoretical interpretations have been developed to explain the appearance of surface reliefs (SR), but only a few of them consider the features of underlying molecular architecture. We have been also working on this problem by pursuing the orientation approach, which establishes a clear relation between the light characteristics and the molecular properties of azo-containing materials. Recently we provided a couple of decisive proofs that reorientation of polymer backbones along the light polarization direction should be the main reason of photoinduced deformations in azopolymer films. The ultimate objective of this project is to develop the viscoplastic modeling approach for complex irradiation patterns. To reach this objective, two limiting cases of linearly and circularly polarized beams should be extended to a general case of elliptical polarization. The model will be refined by comparing its predictions with appearance of SRs inscribed by the interference patterns of spatially varying elliptical polarization. Then we concentrate on the understanding of the spiral surface reliefs and the wavefront sensitivity of photodeformations. The spiral reliefs are inscribed by irradiating a surface of azopolymer sample with tightly focused helical beams. Such beams can be produced by modern optical elements, which significantly extends the possibilities offered by azopolymer-based nanolithography. The optical field of a helical beam is rather complex. We intend to model the appearance of spiral reliefs under action of such a field, to test the validity of orientation approach at extreme irradiation conditions. Underlying molecular parameters will be provided by atomistic modeling of the side-chain azopolymers used in the experiments. When we succeed, not only an ultimate solution of a long-standing mystery of SRs inscription will be provided but also a versatile modeling approach will be developed for practical applications in modern optics and photonics.

能够在光等外部刺激下改变其分子结构的聚合物引起了科学界的极大关注。特别已知的是光敏偶氮聚合物，其由于其高通用性而在不同领域中具有许多应用。在现代工程中，一个特殊的兴趣已经引起了一个独特的机会，以控制依赖于光照射模式的偶氮聚合物薄膜的变形。形貌重构已被用于制备具有光控润湿性的表面、生物技术中的活细胞模板、用于光子应用的大规模复用光栅。已经开发了多种理论解释来解释表面浮雕（SR）的外观，但只有少数考虑潜在的分子结构的特征。我们也一直致力于这个问题，通过追求取向的方法，它建立了一个明确的光特性和含偶氮材料的分子性质之间的关系。最近，我们提供了一些决定性的证据表明，聚合物主链沿光偏振方向的沿着重新取向应该是偶氮聚合物薄膜光致变形的主要原因。本计画的最终目标是发展复杂辐照模式的黏塑性模拟方法。为了达到这个目的，线偏振和圆偏振光束的两种极限情况应该扩展到椭圆偏振的一般情况。该模型将通过将其预测与空间变化的椭圆偏振的干涉图案所刻的SR的外观进行比较来改进。然后，我们集中在螺旋表面浮雕的理解和光变形的波前灵敏度。螺旋浮雕是通过用紧密聚焦的螺旋光束照射偶氮聚合物样品的表面而刻出的。这样的光束可以通过现代光学元件产生，这大大扩展了基于偶氮聚合物的纳米光刻提供的可能性。螺旋光束的光场是相当复杂的。我们打算在这样一个领域的作用下，模拟螺旋浮雕的外观，在极端的照射条件下，测试取向方法的有效性。基本的分子参数将提供的实验中使用的侧链偶氮聚合物的原子模型。当我们成功的时候，不仅将提供一个长期存在的神秘的SRs铭文的最终解决方案，而且还将为现代光学和光子学的实际应用开发一种通用的建模方法。