基于共轭共聚物网络的动态褶皱的多重调控

环境刺激响应的动态微/纳米图案可调节表面特性,为智能表面的按需制备提供了有效的解决方案.我们合成了一种光响应共轭聚合物(P(AEG-AAzo-AAN)),基于简单的策略构建了光驱动的双层动态褶皱图案系统.聚合物所含蒽侧基的光二聚和偶氮苯侧基的光异构化可以分别调节交联密度和应力松弛,从而决定褶皱的产生/擦除,实现多级次褶皱的按需制备.硫酸掺杂后,褶皱图案能够对湿度做出响应,薄膜变为半导体.这种多重响应动态褶皱可能在智能显示器和防伪标签中获得潜在的应用.

Azobenzene-based ultrathin peptoid nanoribbons for the potential on highly efficient artificial light-harvesting

The development of artificial light-harvesting systems based on long-range ordered ultrathin organic nanomaterials(i.e., below3 nm), which were assembled from stimuli-responsive sequence-controlled biomimetic polymers, remains challenging. Herein,we report the self-assembly of azobenzene-containing amphiphilic ternary alternating peptoids to construct photo-responsive ultrathin peptoids nanoribbons(UTPNRs) with a thickness of ~2.3 nm and the length in several micrometers. The pendants hydrophobic conjugate stacking mechanism explained the formation of one-dimensional ultrathin nanostructures, whose thickness was highly dependent on the length of side groups. The photo-isomerization of azobenzene moiety endowed the aggregates with a reversible morphology transformation from UTPNRs to spherical micelles(46.5 nm), upon the alternative irradiation with ultraviolet and visible light. Donor of 4-(2-hydroxyethylamino)-7-nitro-2,1,3-benzoxadiazole(NBD) and acceptor of rhodamine B(RB) were introduced onto the hydrophobic and hydrophilic regions, respectively, to generate photocontrollable artificial light-harvesting systems. Compared with the spheres-based systems, the obtained NBD-UTPNRs@RB composite proved a higher energy transfer efficiency(90.6%) and a lower requirement of RB acceptors in water. A proof-ofconcept use as fluorescent writable ink demonstrated the potential of UTPNRs on information encryption.

化学机械抛光中保持环对抛光液利用率影响的有限元模拟

化学机械抛光(CMP)过程中抛光液占其总成本的50%,抛光液有效利用率却非常低。改进保持环的沟槽结构可以提高抛光液的有效利用率。本工作中,构建了抛光液流动与保持环转动的动态耦合模型,采用有限元方法(FEM)探究了CMP过程中保持环结构(包括沟槽数量、沟槽宽度、沟槽面积以及沟槽处是否为圆角)对抛光液有效利用率的影响。结果表明,同沟槽宽度(3.0 mm)时,抛光液的有效利用率随着保持环沟槽数量的增加而提高。而同沟槽面积(1785.4±0.3 mm^(2))时,保持环沟槽数量增加会导致抛光液的有效利用率下降。在其他条件相同的情况下,圆角型沟槽比尖角型沟槽有更高的抛光液有效利用率。本工作通过FEM优化了CMP工艺参数,为降低CMP成本提供了理论指导。

Regulating the self-assembly of rigid 2D ribbon-like amphiphilic homopolymer via tailoring its holistic conformation

Amphiphilic rigid backbone polymers are traditionally seemed as one-dimensional(1D)rods and show distinct self-assembly behavior to flexible polymers,but they could hardly adapt morphology-tunable self-assembly by changing their holistic conformation upon external stimuli.In this study,we synthesized a series of amphiphilic homopolymers poly(acetylene azobenzene oligoethylene glycol)(P(AAzo-EGx))containing conjugated polyacetylene mainchain,azobenzene pendants and oligo ethylene glycol tails in each unit.This comb-like amphiphilic polymer could be treated as two-dimensional(2D)nanoribbons with tunable holistic conformation via meticulous tailoring intrastrand repulsion and interchainπ-πinteraction of azobenzene pendants by light,temperature,and solvent swelling.P(AAzo-EG_(2))could self-assemble into large vesicles in ambient,whereas transformed to supramolecular helix bundles(SHBs)at 65℃as well as depicted by dissipative particle dynamics(DPD)simulation,and then turned into grass leaf-like micelles upon sequential ultraviolet(UV)and blue light irradiation.The three assemblies featured different stacking mode of PAAzo skeletons although showed similar aggregate induce emission(AIE)effect.In this holistic macromolecular chain conformation-induced self-assembly and morphology transformation,temperature influenced the stacking of hydrophobic parts mainly by tuning the torsion of PAAzo skeleton.Certain amount of good solvent played a vital role by swelling of hydrophobic PAAzo skeleton,and helping the movement and rearrangement of azobenzene pendants and polyacetylene mainchains like a lubricant.The length and diameter of SHBs could be tuned by changing EGxtails.This work uncovered a facile strategy to tailor the self-assembly of rigid backbone polymers for fabrication of functional nanodevices.

Biomimetic ultrathin pepsomes for photo-controllable catalysis

Artificial vesicles for mimicking the unique structures and functions of natural organelles represent a promising scientific object in biomimicry.However,the development of the stimuli-responsive and ultrathin vesicles assembled from sequence-defined biomimetic polymers for controllable applications is still a significant challenge.Herein,we report the self-assembly of azobenzene-based amphiphilic alternating peptoids to generate photo-responsive and ultrathin peptoid vesicle(pepsomes)with an average diameter of∼180 nm.Both cryo-transmission electron microscopy(TEM)and dissipative particle dynamics simulation proved that the vesicular membrane was the ultrathin bilayer structure around∼1.6 nm.The photo-responsive ability of pepsomes was demonstrated by the reversible size changes upon the alternative irradiation with ultraviolet(UV)and visible lights,which was attributable to the photoisomerization virtue of azobenzene moiety.As a proof-of-concept,the photo-controllable catalytic action of gold nanoparticles-decorated pepsomes was evaluated toward the borohydride-mediated reduction from 4-nitrophenol to 4-aminophenol.Photo-controllable reversible and recyclable catalytic activity was effectively modulated using the alternative irradiation with UV and visible lights for five cycles.Our work provides a simple strategy to prepare stimuli-responsive and ultrathin vesicles for potential application on nanocatalysis.

Helical supramolecular nanorods via sequential meticulous tailoring of noncovalent interaction and light irradiation

Polymers are widely recognized to entail random conformations in good solvent governed by the need for achieving the highest entropy to reach thermodynamic equilibrium.In this context,it remains grand challenging to directly arrange them into ordered conformation as building blocks for further self-assembling into hierarchal structures.Herein,we report a simple yet viable strategy to progressively assemble rationally designed azobenzene-containing alternating copolymer(i.e.,poly(binaphthylspacer-azobenzene-alt-hexaethylene glycol),denoting P(BNPSAzo-alt-EG_(6))_(24))into helical supramolecular nanorods.Specifically,P(BNPSAzo-alt-EG_(6))_(24) chains in good solvent are firstly self-assembled into helical single molecular micelles in good solvent via intramolecular π-π interaction between binaphthyl groups as well as between azobenzene moieties.Subsequently,by simply introducing water into the solution that is allowed to dwell for a certain period of time,single molecular micelles are selfassembled into well-defined vesicles.Finally,these isotropic vesicles could be further transformed into anisotropic helical supramolecular nanorods with enhanced aggregate-induced emission(AIE)capability driven by repeated,light-triggered cistrans isomerization of azobenzene moieties with the retention of π-π interacted binaphthyl groups.This study highlights a facile route to yielding morphology-rich,functional assemblies from a single polymer via judiciously exploiting non-covalent interaction and light of different wavelength as highly effective trigger in a non-invasive manner for potential applications in controlled release and fluorescent labelling.