Preparation Of Optical Window Materials Using Ultrasonic Assited Layer-by-layer Self-assembly Techinique

UV blocking and near-IR shielding transparent optical windowmaterial can meet the high quality of modern life. It’s efficient inshielding UV and near IR irradiations and avoids excessive rays fromharming human beings and goods; it can block thermal exchangesbetween indoor and outdoor of buildings and vehicles thus reducing theload of air conditioners; it should be widely applied in fields of rawmaterials for construction, transportation, energy saving, environmentprotection and so on. Up to now, the optical window materials arefabricated through sputtering, deposition and electron beam coatingmethods to obtain metal-reflective coating glasses and sunscreenheat-blocking films. However, the above approaches need expensive andcomplex equipments and costs a lot; products made by these methodshave poor transparency and high reflectivity and metal coatings areaccessible to be oxidized. Hence, a novel strategy towards UV blocking and near-IR shielding transparent optical window materials are urgent tobe developed.Layer-by-layer self-assembly is an important assembly technique toconstruct supramolecular systems, which has several advantages likeconstructing films in a facile and fast way with high quality, and it can bewidely applied. Besides, this technique is not restricted to any sizes andshapes of the substrates. Due to the various designable and tailoredproperties, functional nano-films are widely used in fields such asconstruction, transportation and cosmetic and so on. In this paper, wehave presented a facile and novel method to fabricate functional UVblocking and near-IR shielding transparent films, namelyultrasonic-assisted layer-by-layer self-assembly; by takingpolyethyleneimine and indium tin oxide nanoparticles as building blocks,the effects of introducing ultrasonic waves on the structures of the formedfilms, the quality of film and the film functions, have been investigated.Besides, a dynamic self-assembly mechanism is proposed through thepotential curves. Furthermore, we have combined ultrasonic-assistedlayer-by-layer self-assembly with conventional spin-coating method andtaken functional indium tin oxide nanoparticles and zinc oxidenanoparticles as building blocks, to achieve two kinds of transparentpolymer-nanoparticles composite films. It turns out that the as-preparedfilm displays adjustable properties of UV blocking and near-IR shielding, a high transparency above80%, a efficiency of UV blockingapproximately to80%and near-IR shielding effect more than60%, thusproviding a novel idea and approach to nano-films for energy saving.