Liquid crystal surface anchoring of mesophase pitch

被引：50

作者：

Jian, KQ ^{[1
]}

Shim, HS ^{[1
]}

Tuhus-Dubrow, D ^{[1
]}

Bernstein, S ^{[1
]}

Woodward, C ^{[1
]}

Pfeffer, M ^{[1
]}

Steingart, D ^{[1
]}

Gournay, T ^{[1
]}

Sachsmann, S ^{[1
]}

Crawford, GP ^{[1
]}

Hurt, RH ^{[1
]}

机构：

[1] Brown Univ, Div Engn, Providence, RI 02912 USA

来源：

CARBON | 2003年 / 41卷 / 11期

基金：

美国国家科学基金会;

关键词：

mesophase pitch; texture; optical microscopy; microstructure;

D O I：

10.1016/S0008-6223(03)00203-3

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

Mesophase pitch, in common with other liquid crystalline substances, exhibits preferred angles of molecular orientation at its boundaries with other phases. These orientations, or surface anchoring states, are important because they influence the ultimate graphene layer arrangement in a variety of carbon materials where the pitch precursor encounters a composite filler, a free surface, a bubble cavity, or the surfaces of processing equipment such as a fiber spinneret. This paper presents experimentally determined anchoring states for two mesophase pitches at free surfaces, and on twenty solid substrates. Edge-on anchoring is found to be the most common state, occurring on the free surface, on some metals, on PTFE, and on all oxides with the exception of the lamellar material mica. The optical texture associated with the edge-on films is observed to be stable during carbonization up to 1200 T. Face-on anchoring is observed on carbon graphene planes, mica and the metals Pt, Ni, and Ag. Trends in the data are discussed in terms of the strength of pitch/substrate intermolecular forces relative to pi-pi bonding between large discotic mesogens within the pitch. The implications for the structure and properties of carbon materials are discussed. (C) 2003 Elsevier Ltd. All rights reserved.

引用

页码：2073 / 2083

页数：11

共 43 条

[21] Orthogonal carbon nanofibers by template-mediated assembly of discotic mesophase pitch [J].