Fabrication, functionalization, and exploration of polymer -based rancdevices

我们通过实验证明了聚合物的几种机械性能，如弹性、粘弹性和玻璃化转变温度，在纳米尺度上取决于聚合物的尺寸。据我们所知，这一结果是纳米材料力学性能尺寸效应的首次报道。以直径约200 nm的聚甲基丙烯酸甲酯纳米线为材料，采用双光子光聚合法制备了纳米弹簧。采用激光俘获法对制备的纳米弹簧在溶液中进行操纵，并测量了纳米弹簧的弹性常数。我们在手工制作的激光捕获系统中安装了温度可控阶段，使得纳米弹簧的温度在弹簧常数测量时可以从200 K左右改变到400 K左右。首先，我们发现纳米尺寸聚合物的弹性比相同材料的体积小109倍。这种巨大的弹性与聚合程度或溶液无关，而纯粹取决于聚合物的大小。我们还观察到聚合物的转变温度随聚合物尺寸的不同而发生显著变化。实际上，当纳米弹簧的尺寸从450 nm减小到150 nm时，转变温度降低了40 K以上。实验数据还表明，基于聚合物的纳米器件具有一种新的功能，即可逆的温度可切换弹性/粘弹性。弹性/粘弹性随转变温度的变化实际上在任何聚合物材料中都是固有的，因此并不奇怪，尽管大块聚合物的玻璃化转变温度通常为~ 370 K。然而，通过在纳米尺度上设计聚合物结构的尺寸，即使在室温下也可以控制开关温度。我们还开发了含az -苯单体功能化的新型高分子材料。该聚合物在光照射下表现出折射率变化和体积变化。我们利用双光子聚合制备了三维光子晶体，并演示了光子带隙的光开关。由于偶氮苯衍生物的光异构化引起了折射率和体积变化，因此光子带隙的光开关是可逆的。我们通过这个项目展示的这些新颖的机械和光学功能是纳米级聚合物所固有的，并将导致探索未来新型聚合物纳米器件。少

We experimentally presented proof that several mechanical properties of polymer, such as elasticity, viscoelasticity, and glass transition temperature, are dependent on the size of the polymer in nano meter scale. To our knowledge, this result is the first report of the size -effect on mechanical property of nano materials. We fabricated nano spring made of 〜200 nm diameter poly (methylmethacrylate) nanowire by means of two-photon photopolymerization. We manipulated the fabricated nano spring in solution by laser trapping method, and measured the spring constant of the nano spring. We installed temperature controllable stage into our hand -made laser trapping system, which made it possible to change the temperature of the nano spring from about 200 to 400 K during spring constant measurement. First, we found that the elasticity of nano size polymer is 109 times smaller than that of the bulk of the same material. This giant elasticity is not related to degree of polymerization, or solve … More nt, but purely dependent on the size of polymer. We also observed that transition temperature of the polymer changes remarkably depending on the size of polymer. Actually, the transition temperature decreased more than 40 K when the size of the nano spring was decreased from 450 nm to 150 nm. The experimental data also suggest a novel functionality in polymer based nano devices, which is reversible temperature -switchable elasticity/viscoelasticity. The change of elasticity/viscoelasticity by transition temperature is actually intrinsic in any polymer materials, and so not surprising, though the glass transition temperature of bulk polymer is usually 〜370 K. However by designing the size of polymer structures at the nanoscale, it becomes possible to control the switching temperature, even at room temperature. We also developed new polymer materials functionalized by az o-benzene contained monomers. This polymer shows refractive index change and volume change by light irradiation. We fabricated three -dimensional photonic crystals by two-photon polymeriation, and demonstrated optical switching of photonic bandgaps. Since the refractive index and volume change is induced by photo -isomerization of azo-benzene derivative, the optical switching of photonic bandgaps is reversible. These novel mechanical and optical functions we have shown through this project are intrinsic to nano-sized polymers, and would lead to exploring future novel polymer-based nanodevices. Less