We successfully synthesized two different structures, silica nanospheres and porous polymer membranes, via nanophase separation, based on a sol-gel process. Silica sol, which was in situ polymerized from tetraorthosilicate, was used as a precursor. Subsequently, it was mixed with a polymer that was used as a matrix component. It was observed that nanophase separation occurred after the mixing o...

A variable optical attenuator (VOA) based on polymer stabilized twisted nematic (PSTN) liquid crystal (LC) is demonstrated. Comparing with the normal twisted nematic LC-based VOA, PSTN exhibits a much faster response time. Moreover, the polymer networks effectively eliminate the backflow effect which exists in the normal TNLC cell. The attenuation mechanism of the PSTN LC was studied. Both pola...

The properties of thin polymer films are known to be different than the properties of bulk polymers. Both dewetting studies1,2 and temperature-dependent thickness measurements3 showed that thin polystyrene films can exhibit polymer mobility even at temperatures well below that of the bulk-polymer glass transition (Tg). Subsequent work by a wide range of groups has shown that the thermal propert...

Utilization of membrane humidifiers is one of the methods commonly used to humidify reactant gases in polymer electrolyte membrane fuel cells (PEMFC). In this study, polymeric porous membranes with different compositions were prepared to be used in a membrane humidifier module and were employed in a humidification test. Three different neural network models were developed to investigate several...

Self-oscillating polymer gel has become a distinguished class of smart soft materials. Here we fabricated and demonstrated a self-oscillating structural gel network with the incorporation of the Belousov-Zhabotinsky (BZ) reaction. The structural polymer gel oscillates at a macroscopic level with remarkably faster kinetics compared to a normal gel of similar chemical compositions. The structural...

A statistical theory was proposed for the degradation (random scission of chains) of a network having f-functional nodes in the case where all chains contain equireactive groups and a chain scission event does not create new groups or suppress more than one group. Closedform relations were established between the conversion ratio of the degradation process and the crosslink density. Emphasis wa...

Stimuli-responsive polymer hydrogels which are capable of responding to changes in their environment such as pH (1), osmotic strength (2), or temperature (3) have received growing attention in recent years for applications in a wide variety of areas including controlled drug delivery (4). Also, due to the size limitations imposed by the body’s natural defense mechanisms, such as the reticuloend...

An axially-symmetric sheared polymer network liquid crystal (SPNLC) device is demonstrated and its performances characterized. Through analyzing the structure of this axially-symmetric SPNLC, we constructed a 3-D model to explain the observed phenomena. The simulation results agree well with the experiment. Two potential applications of such an axially-symmetric SPNLC, namely tunable-focus nega...

Natural polymers such as proteins and polysaccharides though very useful exhibit a limitation in their reactivity and process ability. These shortcomings were overcome by chemical and physical alteration of natural polymers. Among various investigations, the interpenetrating polymer networks (IPNs) for hydro gels have attracted much attention. It is a combination of at least two polymer chains ...