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Volumn 22, Issue 4, 2006, Pages 1711-1714

Designing for optimum liquid repellency

Author keywords

[No Author keywords available]

Indexed keywords

LIQUID REPELLENCY; SUPER REPELLENT SURFACES; SUSPENSION PRESSURES;

EID: 33644553153     PISSN: 07437463     EISSN: None     Source Type: Journal    
DOI: 10.1021/la052540l     Document Type: Article
Times cited : (142)

References (45)
  • 10
    • 0032634742 scopus 로고    scopus 로고
    • Chen, W.; et al. Langmuir 1999, 15, 3395.
    • (1999) Langmuir , vol.15 , pp. 3395
    • Chen, W.1
  • 19
    • 33644513662 scopus 로고    scopus 로고
    • note
    • Super repellency also is referred to as super or ultra lyophobicity. If the liquid is water, then it is termed super hydrophobicity.
  • 25
    • 33644556083 scopus 로고    scopus 로고
    • note
    • Teflon is a registered trademark of DuPont.
  • 29
    • 33644516547 scopus 로고    scopus 로고
    • note
    • The most widely known form of Teflon is poly(tetrafluoroethylene) (PTFE), which is comprised solely of fluoromethylene groups. If smooth, PTFE has a contact angle of approximately 110°. DuPont manufactures a number of PTFE copolymers that are sold under the Teflon trademark, such as fluorinated ethylene propylene (FEP), perfluoroalkoxy (PFA), and an amorphous 2,2-bistrifluoromethyl-4,5-difluoro-1,3-dioxole (PDD)/tetrafluoroethylene (TFE) copolymer (Teflon AF). These copolymers all contain comonomers with side chains that are fluoromethyl terminated. Among these, the PDD/TFE copolymer contains the highest number of fluoromethyl groups and consequently can show contact angles as high as 130°. Other fluorocarbon compounds, such as fluorowaxes and fluorosurfactants, also can be used to create smooth layers that show water contact angles in excess of 120°.
  • 30
    • 33644507029 scopus 로고    scopus 로고
    • note
    • a.
  • 32
    • 33644520204 scopus 로고    scopus 로고
    • note
    • Eq 4 is for a flat horizontal sheet of liquid. The suspension pressures required to repel impinging drops will be somewhat larger.
  • 33
    • 33644533456 scopus 로고    scopus 로고
    • note
    • Even though drop curvature increases the downward pressure above and beyond that associated with the height of the liquid drop, a suspension pressure that successfully repels a column of liquid will easily repel small residual drops.
  • 39
    • 33644546339 scopus 로고    scopus 로고
    • note
    • The early papers on drop retention cited here assume a constant advancing contact angle at the front of the drop and a constant receding value at the rear. Although this may be approximately true for elongated drops, it is not the case for drops with circular contact lines. If drops are not stretched much, which is the case for super repellent surfaces, then their contact line remains circular, and the contact angle varies continuously from front to back. The pre-factor in eq 8 arises from integrating the dot product of the liquid surface tension and the cosine of the contact angle from the advancing value at the front of the drop to the receding value at the rear.
  • 41
    • 0023978140 scopus 로고
    • If very small drops with diameters equal to or less than asperity spacing fall between asperities, these drops may behave differently. Small drops entering pores have been studied by Marmur, A. J. Colloid Interface Sci. 1988, 122, 209.
    • (1988) J. Colloid Interface Sci. , vol.122 , pp. 209
    • Marmur, A.1


* 이 정보는 Elsevier사의 SCOPUS DB에서 KISTI가 분석하여 추출한 것입니다.