The organization of 2,3-iron-naphthalocyanine molecules on substrate as revealed by scanning tunneling microscopy

Surface morphology of thin molecular layer of 2,3-Iron-naphthalocyanine (2,3 FeNPc) was studied by scanning tunneling microscopy (STM) at the ambient conditions. Organic layer with thickness of 40 nm was vapour phase deposited on amorphous carbon substrate. The STM images have revealed the pecularities of surface molecular organization from large range (hundreds of nm) down to atomic scale. Arrays of locally ordered linear stuctures have been distinguished as the main morphological features of the examined surface. At several places the well-ordered STM patterns have been distinguished at the atomic scale. They can be described as stacks of periodicity approximatelly 0.4 nm in a row and 1.5 nm between stacks. These results can be explained by arrangement of 2,3-FeNPh molecules in stacks with a main plane being perpendicular to the substrate surface

Atomic force microscopy of gel-drawn ultrahigh-molecular-weight polyethylene

Gel-drawn ultrahigh molecular weight polyethylene was studied by atomic force microscopy (AFM). Three-dimensional surface profiles were recorded for tapes drawn to different extents. AFM images allowed the discrimination of different well-defined levels of the fibrillar morphology: (i) bundles of microfibrils with a diameter between 4 and 7 μm strongly depending on the elongation; (ii) microfibrils with a diameter between 0.2 and 1.2 nm which also decreased with increasing draw ratio; (iii) nanofibrils which form the elementary fibrillar building blocks; and (iv) regular chain patterns on the molecular level which correspond to the crystalline packing of polyethylene chains at the surface of the nanofibrils. The nanofibrils were formed during the initial conversion of lamellae to fibrillar crystallites and did not change considerably in diameter up to draw ratios of λ = 70

Organic–inorganic interfaces and spiral growth in nacre

Nacre, the crown jewel of natural materials, has been extensively studied owing to its remarkable physical properties for over 160 years. Yet, the precise structural features governing its extraordinary strength and its growth mechanism remain elusive. In this paper, we present a series of observations pertaining to the red abalone (Haliotis rufescens) shell's organic–inorganic interface, organic interlayer morphology and properties, large-area crystal domain orientations and nacre growth. In particular, we describe unique lateral nano-growths and paired screw dislocations in the aragonite layers, and demonstrate that the organic material sandwiched between aragonite platelets consists of multiple organic layers of varying nano-mechanical resilience. Based on these novel observations and analysis, we propose a spiral growth model that accounts for both [001] vertical propagation via helices that surround numerous screw dislocation cores and simultaneous 〈010〉 lateral growth of aragonite sheet structure. These new findings may aid in creating novel organic–inorganic micro/nano composites through synthetic or biomineralization pathways

Surface structure of polymers and their model compounds observed by atomic force microscopy

Results of atomic force microscopy (AFM) of normal alkanes, polyethylene, isotactic polypropylene and of a diblock copolymer are presented. Various types of surfaces - naturally and epitaxially grown on different substrates - have been examined from hundreds of nanometers down to the atomic scale. Surface morphology and molecular arrangement have been visualized in AFM images. Atomic-scale AFM images with some defects have been observed on lamellar surfaces of normal alkanes C33H68. Arrays of oriented polyethylene molecules have been revealed at the surface of thin polyethylene films, epitaxially crystallized on the (001) face of an anthracene single crystal. Contact faces of thin films of isotactic polypropylene (iPP), epitaxially crystallized on various substrates (i.e. benzoic acid, potassium salt of 4-chloro-benzoic acid or polyamide 11), show the lamellar structure as well as the methyl side-group pattern in the exposed iPP (010) planes. AFM offers the way to distinguish the crystalline modification as well as the molecular conformation (left- and right-handed helices). Also the morphology of a microphase-separated block copolymer, polystyrene-b-poly-(2-vinylpyridine) (PS/PVP), has been observed by AFM