Delicate modification of poly(dimethylsiloxane) ultrathin film by low-energy ion beam treatment for durable intermediate liquid crystal pretilt angles.
Long-term stability of intermediate liquid crystal pretilt angles on a poly(dimethylsiloxane) (PDMS) ultrathin film grafted onto a surface was realized simply and easily via low-energy ion beam (IB) treatment. The composition and surface energy of the thin film could be controlled by varying the low-energy IB treatment. This treatment results in the permanent chemical modification of the film surface, converting it from organic PDMS to a mixed layer of organic PDMS and inorganic silica. The partial transformation of a PDMS surface gives rise to the control of the pretilt angle via the formation of the inhomogeneous surface and the stabilization of the pretilt angle via the cross-linking reaction of broken chemical bonds through IB irradiation. As a result, a continuous variation of pretilt angles that maintained their initial value with long-term stability was obtained. Thus, the unique chemical transformation of the PDMS surface using IB treatment may allow for the production of durable intermediate liquid crystal pretilt angles.
Hwang
Byoung Har
BH
Department of Materials Science and Engineering, Yonsei University, Shinchon-Dong 134, Seodaemun-Gu, Seoul 120-749, Korea.
Choi
Chu Ji
CJ
Jo
Min Kyoung
MK
Kim
Jong Bok
JB
Choe
Hae Min
HM
Chae
Soo Sang
SS
Kim
Youn Sang
YS
Baik
Hong Koo
HK
D004129:Dimethylpolysiloxanes / Q000737:chemistry*; D050866:Liquid Crystals / Q000737:chemistry*; D008567:Membranes, Artificial; D012822:Silicon Dioxide / Q000737:chemistry; D013499:Surface Properties
D004129:Dimethylpolysiloxanes; D008567:Membranes, Artificial; C013830:baysilon; D012822:Silicon Dioxide