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In Situ Probing the Relaxation Properties of Ultrathin Polystyrene Films by Using Electric Force Microscopy

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ABSTRACT

The rapid development of nanoscience and nanotechnology involves polymer films with thickness down to nanometer scale. However, the properties of ultrathin polymer films are extremely different from that of bulk matrix or thin films. It is challenging to distinguish the changes of physical properties in ultrathin films using conventional techniques especially when it locates near the glass transition temperature (Tg). In this work, we successfully evaluated a series of physical properties of ultrathin polystyrene (PS) films by in situ characterizing the discharging behavior of the patterned charges using electric force microscopy. By monitoring the surface potential in real time, we found that the Tg of ultrathin PS films is clearly independent of film thickness, which are greatly different from that of thin PS films (film thickness larger than 10 nm).

No MeSH data available.


a Schematic illustration of the fabrication of PDMS stamps and b the in situ monitoring of discharging behavior
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Fig1: a Schematic illustration of the fabrication of PDMS stamps and b the in situ monitoring of discharging behavior

Mentions: The schematic fabrication processes of PDMS stamps and patterned charges were illustrated in Fig. 1. PDMS prepolymer was poured on an optical lithographed silicon wafer with micro-structures and cured at a temperature of 348 K for 2 h. Then, the cured PDMS polymer was peeled off from the silicon substrate, and a 10-nm Cr adhesive layer and 100 nm Au conductive layer was deposited on it, forming a conductive micro-patterned PDMS stamp. The conductive PDMS stamp was then placed in close contact with the PS film supported on Si substrate to form a parallel-plate capacitor. A Keithley 2400 source meter supplied a 10 kV cm−1 electrical field between the PDMS stamp and the silicon substrate. The charge patterns were successfully fabricated and characterized using EFM.Fig. 1


In Situ Probing the Relaxation Properties of Ultrathin Polystyrene Films by Using Electric Force Microscopy
a Schematic illustration of the fabrication of PDMS stamps and b the in situ monitoring of discharging behavior
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5383798&req=5

Fig1: a Schematic illustration of the fabrication of PDMS stamps and b the in situ monitoring of discharging behavior
Mentions: The schematic fabrication processes of PDMS stamps and patterned charges were illustrated in Fig. 1. PDMS prepolymer was poured on an optical lithographed silicon wafer with micro-structures and cured at a temperature of 348 K for 2 h. Then, the cured PDMS polymer was peeled off from the silicon substrate, and a 10-nm Cr adhesive layer and 100 nm Au conductive layer was deposited on it, forming a conductive micro-patterned PDMS stamp. The conductive PDMS stamp was then placed in close contact with the PS film supported on Si substrate to form a parallel-plate capacitor. A Keithley 2400 source meter supplied a 10 kV cm−1 electrical field between the PDMS stamp and the silicon substrate. The charge patterns were successfully fabricated and characterized using EFM.Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

The rapid development of nanoscience and nanotechnology involves polymer films with thickness down to nanometer scale. However, the properties of ultrathin polymer films are extremely different from that of bulk matrix or thin films. It is challenging to distinguish the changes of physical properties in ultrathin films using conventional techniques especially when it locates near the glass transition temperature (Tg). In this work, we successfully evaluated a series of physical properties of ultrathin polystyrene (PS) films by in situ characterizing the discharging behavior of the patterned charges using electric force microscopy. By monitoring the surface potential in real time, we found that the Tg of ultrathin PS films is clearly independent of film thickness, which are greatly different from that of thin PS films (film thickness larger than 10 nm).

No MeSH data available.