scholarly journals Recruiting physisorbed water in surface polymerization for bio-inspired materials of tunable hydrophobicity

2016 ◽  
Vol 4 (38) ◽  
pp. 14729-14738 ◽  
Author(s):  
S. Oyola-Reynoso ◽  
I. D. Tevis ◽  
J. Chen ◽  
B. S. Chang ◽  
S. Çinar ◽  
...  
Keyword(s):  
Surface Energy ◽  
Surface Properties ◽  
Surface Polymerization ◽  
Physisorbed Water ◽  
Chemical Grafting ◽  
Properties Of Materials

Chemical grafting has been widely used to modify the surface properties of materials, especially surface energy for controlled wetting, because of the resilience of such coatings/modifications.

Effect of Polymer Substrates on Nano Scale Hot Embossing

2003 ◽  
Vol 782 ◽  
Author(s):  
Jin-Hyung Lee ◽  
Hyun-Woo Lim ◽  
Jin-Goo Park ◽  
Eun-Kyu Lee ◽  
Yangsun Kim
Keyword(s):  
Surface Energy ◽  
Surface Properties ◽  
Process Development ◽  
Adhesion Force ◽  
Polymer Surface ◽  
Hot Embossing ◽  
Surface Characteristic ◽  
Direct Writing ◽  
Polymer Substrates ◽  
Nano Size

ABSTRACTHot embossing has been widely accepted as an alternative to photolithography in generating patterns on polymer substrates. The optimization of embossing process should be accomplished based on polymer surface properties. Therefore, in this paper, polymers with different surface characteristic were selected and the surface properties of each polymers such as surface energy and adhesion force were investigated by contact angle and AFM. Based on these results, the imprinted nano patterns were compared. Silicon molds with nano size patterns were fabricated by e-beam direct writing. Molds were coated with self-assembled monolayer (SAM) of (1, 1, 2, 2H –perfluorooctyl)-trichlorosilane to reduce the stiction between molds and polymer substrates. For embossing, pressure of 500 psi, embossing time of 5 min and temperature of above transition temperature were applied. Mr-I 8010 polymer (Micro Resist Technology), Polymethylmethacrylate (PMMA 495k) and LOR (polyaliphatic imide copolymer) were used as substrate for hot embossing process development in nano size. These polymers were spun coated on the Si wafer with the thickness of 150 nm. The nano size patterns obtained by hot embossing were identified by atomic force microscopy without breaking the pattern and compared based on the polymer surface properties. The mr-I 8010 which has the lowest surface energy and adhesion force shows the best demolding property.

Crystallographic anisotropy in surface properties of brass and its dependence on the electron work function

2018 ◽  
Vol 51 (6) ◽  
pp. 1715-1720 ◽  
Author(s):  
Liqiu Guo ◽  
Hao Lu ◽  
D. Y. Li ◽  
Q. X. Huang ◽  
Xu Wang ◽  
...  
Keyword(s):  
Surface Energy ◽  
Work Function ◽  
Surface Properties ◽  
Electron Work Function ◽  
Adhesive Force ◽  
Surface Electron ◽  
Crystallographic Anisotropy ◽  
Atomic Force ◽  
Work Functions ◽  
Crystallographic Planes

The crystallographic anisotropy of the electric current or conductance, adhesive force, elastic modulus, and deformation magnitude of alpha brass were investigated through property mapping using an atomic force microscope. Surface electron work functions of differently oriented grains in the brass were also analyzed using atomic force microscopy. The mapped surface properties are closely related to the electron work function; the work function reflects the surface activity, which is itself dependent on the surface energy. The anisotropy of the properties is closely correlated to the in situ measured surface electron work function. It is demonstrated that crystallographic planes with higher electron work functions exhibit lower current, smaller adhesive forces, larger elastic moduli and smaller deformation magnitudes. Efforts are made to understand the relationships by connecting the properties with surface energy and electron work function. The dependence of the properties on crystallographic orientation can be elucidated by considering the surface electron behavior using electron work function as a novel probing parameter.

Using Atomic Force Microscopy to Retrieve Nanomechanical Surface Properties of Materials

2006 ◽  
Vol 514-516 ◽  
pp. 1598-1602 ◽  
Author(s):  
Sergio Graça ◽  
Rogerio Colaço ◽  
Rui Vilar
Keyword(s):  
Atomic Force Microscopy ◽  
Surface Properties ◽  
Application Rate ◽  
Critical Parameters ◽  
Nanomechanical Property ◽  
Force Microscopy ◽  
Atomic Force ◽  
Properties Of Materials ◽  
Microscopy Techniques ◽  
Scratch Tests

When atomic force microscopy is used to retrieve nanomechanical surface properties of materials, unsuspected measurement and instrumentation errors may occur. In this work, some error sources are investigated and operating and correction procedures are proposed in order to maximize the accuracy of the measurements. Experiments were performed on sapphire, Ni, Co and Ni-30%Co samples. A triangular pyramidal diamond tip was used to perform indentation and scratch tests, as well as for surface visualization. It was found that nonlinearities of the z-piezo scanner, in particular the creep of the z-piezo, and errors in the determination of the real dimensions of tested areas, are critical parameters to be considered. However, it was observed that there is a critical load application rate, above which the influence of the creep of the z-piezo can be neglected. Also, it was observed that deconvolution of the tip geometry from the image of the tested area is essential to obtain accurate values of the dimensions of indentations and scratches. The application of these procedures enables minimizing the errors in nanomechanical property measurements using atomic force microscopy techniques.

Effect of Surface Properties on Particle Growth Kinetics for Polymer Coating in Spouted Bed

2012 ◽  
Vol 727-728 ◽  
pp. 1616-1621 ◽  
Author(s):  
Boeira Braga Matheus ◽  
Cristina dos Santos Rocha Sandra
Keyword(s):  
Surface Energy ◽  
Surface Properties ◽  
Growth Kinetics ◽  
Particle Growth ◽  
Operating Conditions ◽  
Polymeric Film ◽  
Spouted Bed ◽  
Particle Coating ◽  
Solids Concentration ◽  
Before And After

In this research, glass beads with size range between 1.68 and 2mm were coated with 5 polymeric suspensions. The suspensions formulations differ in relation to their employment and physical properties (solids concentration, surface tension and rheology), generating different characteristics of wettability and adhesion with the nucleus. The aim of this study was to evaluate particle coating in a spouted bed through analysis of particle growth in terms of solid surface energy, wettability, and adhesion before and after the formation of the first layer of polymeric film on the particle. The solid-suspension and film-suspension systems were characterized by contact angle and surface energy. The operating conditions were fixed for all suspensions: 1.5 kg of beads, air velocity of 0.369 m/s, air temperature of 60 °C, suspension flow rate of 4 ml and atomizing pressure of 10 psig. Analyzing particle growth kinetics, different behaviors were observed and related not only to glass-suspension wettability, but also to polymeric film-suspension surface properties.

scholarly journals Influence of Solvent and Substrate on Hydrophobicity of PLA Films

Polymers ◽  
2021 ◽  
Vol 13 (24) ◽  
pp. 4289
Author(s):  
Verónica Luque-Agudo ◽  
Amparo M. Gallardo-Moreno ◽  
María Luisa González-Martín
Keyword(s):  
Surface Tension ◽  
Polylactic Acid ◽  
Surface Properties ◽  
Bacterial Adhesion ◽  
Spatial Arrangement ◽  
Methyl Groups ◽  
Solvent Casting ◽  
Properties Of Materials ◽  
The Right ◽  
Influence Of Solvent

The study of the surface properties of materials is key in determining whether the material will be suitable for medical purposes. One of these properties is hydrophobicity, which is important when assessing its behavior against bacterial adhesion. In this work, we have studied the influence of the solvent (chloroform, acetone, and tetrahydrofuran) and the substrate (glass, PTFE, silicone, and Ti6Al4V) on which polylactic acid is deposited in solution to manufacture films by solvent-casting. Thus, it has been found that there are no significant differences in hydrophobicity and surface tension among the solvents evaluated, but there are significant differences with respect to the substrates: PLA films casted on silicone are hydrophobic, while those casted on the rest of the substrates are hydrophilic. This is related to the fact that the silicone interacts with the polymer modifying its spatial arrangement, exposing its methyl groups towards the interface with the air. In this way, it has been shown that, when manufacturing PLA films, it is important to choose the right surface on which to deposit them, depending on their desired function.

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