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1.
ACS Appl Mater Interfaces ; 10(4): 4057-4065, 2018 Jan 31.
Article in English | MEDLINE | ID: mdl-29355298

ABSTRACT

Plasmachemical deposition is a substrate-independent method for the conformal surface functionalization of solid substrates. Structurally well-defined pulsed plasma deposited poly(1-allylimidazole) layers provide surface imidazole linker groups for the directed liquid-phase epitaxial (layer-by-layer) growth of metal-organic frameworks (MOFs) at room temperature. For the case of microporous [Zn (benzene-1,4-dicarboxylate)-(4,4'-bipyridine)0.5] (MOF-508), the MOF-508a polymorph containing two interpenetrating crystal lattice frameworks undergoes orientated Volmer-Weber growth and displays CO2 gas capture behavior at atmospheric concentrations in proportion to the number of epitaxially grown MOF-508 layers.

2.
ACS Appl Mater Interfaces ; 8(33): 21832-8, 2016 Aug 24.
Article in English | MEDLINE | ID: mdl-27505445

ABSTRACT

Click thiol-ene chemistry is demonstrated for the reaction of thiol containing molecules with surface alkene bonds during electrical discharge activation. This plasmachemical reaction mechanism is shown to be 2-fold for allyl mercaptan (an alkene and thiol group containing precursor), comprising self-cross-linked nanolayer deposition in tandem with interfacial cross-linking to the surface alkene bonds of a polyisoprene base layer. A synergistic multilayer structure is attained which displays high wet electrical barrier performance during immersion in water.

3.
ACS Appl Mater Interfaces ; 6(10): 7504-11, 2014 May 28.
Article in English | MEDLINE | ID: mdl-24786299

ABSTRACT

Smooth copolymer-fluorosurfactant complex film surfaces are found to exhibit fast oleophobic-hydrophilic switching behavior. Equilibration of the high oil contact angle (hexadecane = 80°) and low water contact angle (<10°) values occurs within 10 s of droplet impact. These optically transparent surfaces display excellent antifogging and self-cleaning properties. The magnitude of oleophobic-hydrophilic switching can be further enhanced by the incorporation of surface roughness to an extent that it reaches a sufficiently high level (water contact angle <10° and hexadecane contact angle >110°), which, when combined with the inherent ultrafast switching speed, yields oil-water mixture separation efficiencies exceeding 98%.

4.
J Colloid Interface Sci ; 421: 44-8, 2014 May 01.
Article in English | MEDLINE | ID: mdl-24594030

ABSTRACT

Well-defined alkyl chain side group polymer brushes have been tethered onto high surface area macroporous pulsed plasmachemical emulsion-templated poly(vinylbenzyl chloride) initiator layers (typically 600-700 m2 g(-1)) using atom transfer radical polymerisation (ATRP). Immobilisation of phospholipids onto these bioactive surfaces is found to occur through interdigitation, and the efficacy of lipid binding is governed by the alkyl side group chain length of the polymer brushes.


Subject(s)
Emulsions , Lipids/chemistry , Polymerization , Microscopy, Fluorescence , Spectroscopy, Fourier Transform Infrared , Surface Properties
5.
ACS Appl Mater Interfaces ; 5(19): 9678-83, 2013 Oct 09.
Article in English | MEDLINE | ID: mdl-24079883

ABSTRACT

Atomized spray plasma deposition (ASPD) using a precursor mixture of 2-hydroxyethyl methacrylate and methacryloyl-functionalized 15 nm silica nanoparticles leads to the formation of poly(2-hydroxyethyl methacrylate)-silica nanocomposite layers. The direct application of these coatings to overlapping glass-glass joints gives rise to excellent in situ adhesion reaching 84 MPa shear bond strength and 6 GPa shear modulus prior to the onset of adherent (bulk glass) failure. This significant enhancement in interfacial adhesion arises due to the silica nanoparticle surface methacryloyl groups enhancing cross-linking throughout the nanocomposite layer.

6.
ACS Appl Mater Interfaces ; 4(12): 6747-51, 2012 Dec.
Article in English | MEDLINE | ID: mdl-23193941

ABSTRACT

Non-equilibrium plasmachemical deposition using platinum(II) hexafluoroacetylacetonate precursor leads to the single-step formation of nanocomposite layers comprising an organic host matrix embedded with metal particles of size less than 5 nm. These multifunctional nanocomposite films are found to display both ionic and electronic conductivities.

7.
Langmuir ; 28(38): 13712-9, 2012 Sep 25.
Article in English | MEDLINE | ID: mdl-22966860

ABSTRACT

Two-dimensional hexagonally ordered honeycomb surfaces have been created by solvent casting polybutadiene films under controlled humidity. Subsequent CF(4) plasmachemical fluorination introduces cross-linking and surface texturing, leading to hierarchical surfaces with roughness on both the 10 µm (honeycomb) and micrometer (texturing) length scales. For microliter droplets, these display high water contact angle values (>170°) in combination with low contact angle hysteresis (i.e., superhydrophobicity) while displaying bouncing of picoliter water droplets. In the case of picoliter droplets, it is found that surfaces which exhibit similar static contact angles can give rise to different droplet impact dynamics, governed by the underlying surface topography. These studies are of relevance to technological processes such as rapid cooling, delayed freezing, crop spraying, and inkjet printing.


Subject(s)
Fluorocarbons/chemistry , Butadienes/chemistry , Elastomers/chemistry , Humidity , Hydrophobic and Hydrophilic Interactions , Particle Size , Surface Properties
8.
ACS Appl Mater Interfaces ; 4(3): 1675-82, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22409149

ABSTRACT

Graft polymerization of sulfonic acid monomers onto structurally well-defined pulsed plasma poly(maleic anhydride) layers yields a composite carboxylic acid-sulfonic acid network. These bifunctional films are shown to exhibit high proton conductivity (125 mS cm(-1)) as well as good stability in water.

9.
Indian J Virol ; 23(1): 75-9, 2012 Jun.
Article in English | MEDLINE | ID: mdl-23730008

ABSTRACT

Apple is the major commercial horticulture crop in Himachal Pradesh and other hill states of Jammu & Kashmir, Uttarakhand and some parts of Northeastern states of India. In order to gather data on health status and incidence of virus and virus-like pathogens in apple orchards, survey was conducted in the month of June and September, 2010 in Hatkoti, Rohru, Kuthara, Jubbal and Khadapathar areas of major apple producing Shimla district of Himachal Pradesh. A total of 250 samples were collected and analyzed by DAS-ELISA, NASH and RT-PCR. NASH results indicated that a total of 117 samples were infected with Apple chlorotic leaf spot virus (ACLSV), Apple mosaic virus (ApMV), Apple stem grooving virus (ASGV), Apple stem pitting virus (ASPV) and Apple scar skin viroid (ASSVd). Results showed that ASSVd is predominant in these areas with highest infection rate of 27.6% followed by ASPV (17.2%), ACLSV (16.8%), ApMV (15.2%) and ASGV (12%). Mixed infection of these viruses and viroid was frequently detected in apple trees in Himachal Pradesh. The trees, which were positive for viruses and viroids, showed a variety of fruit deformation and rusting symptoms besides leaf deformation, mosaic and chlorosis.

10.
Langmuir ; 27(23): 14151-9, 2011 Dec 06.
Article in English | MEDLINE | ID: mdl-22029905

ABSTRACT

Surface-tethered bottlebrushes have been prepared by ATRP grafting of the macroinitiator brush backbone onto plasmachemical-deposited poly(vinylbenzyl chloride) initiator nanofilms followed by ATRP growth of the side chains (bristles). The surface density of bottlebrushes can be precisely tailored by varying the plasmachemical deposition parameters employed for producing the poly(vinylbenzyl chloride) initiator nanolayers. Lateral force scanning probe microscopy has shown that poly(glycidyl methacrylate)-graft-poly(sodium styrene sulfonate) bottlebrush-decorated surfaces give rise to an enhancement in lubrication.


Subject(s)
Nanostructures/chemistry , Polymers/chemistry , Polymethacrylic Acids/chemistry , Styrenes/chemistry , Sulfonic Acids/chemistry , Molecular Structure , Surface Properties
11.
Langmuir ; 27(22): 13897-903, 2011 Nov 15.
Article in English | MEDLINE | ID: mdl-22011196

ABSTRACT

The impact of picoliter-sized water droplets on superhydrophobic CF(4) plasma fluorinated polybutadiene surfaces is investigated with high-speed imaging. Variation of the surface topography by plasmachemical modification enables the dynamics of wetting to be precisely controlled. Final spreading ratios as low as 0.63 can be achieved. A comparison of the maximum spreading ratio and droplet oscillation frequencies to models described in the literature shows that both are found to be much lower than theoretically predicted.

12.
ACS Appl Mater Interfaces ; 3(6): 2051-6, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21612222

ABSTRACT

ß-cyclodextrin barrels can be tethered to solid surfaces using the Williamson ether synthesis reaction via an intermediate pulsed plasma deposited poly(4-vinylbenzyl chloride) linker layer. The loading and release of perfume molecules through host-guest inclusion complex formation with surface tethered ß-cyclodextrin has been followed by infrared spectroscopy and quartz crystal microbalance measurements. Fragrance release lasts for several months and can be easily recharged.

13.
Langmuir ; 27(7): 3798-802, 2011 Apr 05.
Article in English | MEDLINE | ID: mdl-21381707

ABSTRACT

Conventional fog-harvesting mechanisms are effectively pseudo-2D surface phenomena in terms of water droplet-plant interactions. In the case of the Cotula fallax plant, a unique hierarchical 3D arrangement formed by its leaves and the fine hairs covering them has been found to underpin the collection and retention of water droplets on the foliage for extended periods of time. The mechanisms of water capture and release as a function of the surface 3D structure and chemistry have been identified. Of particular note is that water is retained throughout the entirety of the plant and held within the foliage itself (rather than in localized regions). Individual plant hairs form matlike structures capable of supporting water droplets; these hairs wrap around water droplets in a 3D fashion to secure them via a fine nanoscale groove structure that prevents them from easily falling to the ground.

14.
ACS Appl Mater Interfaces ; 3(4): 1204-9, 2011 Apr.
Article in English | MEDLINE | ID: mdl-21417398

ABSTRACT

A lift-off method for creating multifunctional patterned surfaces has been devised. It entails consecutive pulsed plasmachemical deposition of a reactive bottom layer and a protective top release layer. By way of example, a bottom/top layer combination comprising pulsed plasma deposited poly(glycidyl methacrylate)/poly(pentafluorostyrene) has been shown to display selective adhesive lift-off of the latter. Application of a prepatterned adhesive template yields well-defined arrays of reactive epoxide functionality surrounded by a passive fluoropolymer background or vice versa.

15.
Langmuir ; 26(14): 12342-50, 2010 Jul 20.
Article in English | MEDLINE | ID: mdl-20540557

ABSTRACT

Patterned polymer brush surfaces have been fabricated using the molecular scratchcard lithography technique, where a functional top nanolayer (acting also as a resist) is selectively removed using a scanning probe tip to expose underlying atom-transfer radical polymerization (ATRP) initiator sites. The lateral spreading of grafted polymer brush patterns across the adjacent functional resist surface can be reversibly actuated via solvent exposure. Effectively, this methodology provides a means for hiding/unveiling functional surfaces on the nanoscale.


Subject(s)
Nanostructures/chemistry , Nanotechnology/methods , Methacrylates/chemistry , Microscopy, Atomic Force , Polyvinyls/chemistry , Spectrophotometry, Infrared , Surface Properties
16.
J Am Chem Soc ; 131(22): 7755-61, 2009 Jun 10.
Article in English | MEDLINE | ID: mdl-19438244

ABSTRACT

We describe microarraying of carbohydrates for protein screening using either disulfide bridge or Schiff base imine immobilization chemistries on plasmachemical deposited functional nanolayers. The commonly observed issue of nonspecific background binding of proteins is overcome by spotting carbohydrates through a protein-resistant overlayer yielding spatially localized interaction with a reactive functional underlayer.


Subject(s)
Carbohydrates/chemistry , Microarray Analysis/methods , Aniline Compounds/chemistry , Concanavalin A/chemistry , Disulfides/chemistry , Fluorescent Dyes/chemistry , Glycols/chemistry , Maltose/chemistry , Microscopy, Fluorescence , Nanotechnology/methods , Peanut Agglutinin/chemistry , Protein Binding , Spectroscopy, Fourier Transform Infrared , Sulfhydryl Compounds/chemistry , Sulfonic Acids/chemistry , Vinyl Compounds/chemistry
17.
ACS Appl Mater Interfaces ; 1(12): 2763-7, 2009 Dec.
Article in English | MEDLINE | ID: mdl-20356154

ABSTRACT

Existing methods for imparting antibacterial performance to solid surfaces tend to either be substrate-specific or rely upon leaching modes of action that cause ecological damage. An alternative approach is outlined comprising plasmachemical functionalization of solid surfaces with poly(4-vinyl pyridine) moieties and their subsequent activation (quaternization) with bromobutane to yield bactericidal activity. These bioactive surfaces can be applied to a host of different substrate materials and are easily regenerated by rinsing in water.


Subject(s)
Anti-Bacterial Agents/pharmacology , Hydrocarbons, Brominated/pharmacology , Klebsiella pneumoniae/drug effects , Staphylococcus aureus/drug effects , Anti-Bacterial Agents/chemistry , Colony Count, Microbial , Hydrocarbons, Brominated/chemistry , Klebsiella pneumoniae/growth & development , Microbial Sensitivity Tests , Photoelectron Spectroscopy , Pyridines/chemistry , Pyridines/pharmacology , Spectroscopy, Fourier Transform Infrared , Staphylococcus aureus/growth & development , Surface Properties/drug effects
18.
Langmuir ; 23(2): 689-93, 2007 Jan 16.
Article in English | MEDLINE | ID: mdl-17209621

ABSTRACT

A simple two-step plasmachemical methodology is outlined for the fabrication of microcondensor surfaces. This comprises the creation of a superhydrophobic background followed by pulsed plasma deposition of a hydrophilic polymer array. Microcondensation efficiency has been explored in terms of the chemical nature of the hydrophilic pixels and their dimensions. These results are compared to the hydrophilic-hydrophobic pattern present on the Stenocara beetle's back, which is used by the insect to collect water in the desert. Potential applications include fog harvesting, microfluidics, and biomolecule immobilization.


Subject(s)
Chemistry, Physical/methods , Animals , Butadienes/chemistry , Coleoptera , Elastomers/chemistry , Fluorine/chemistry , Materials Testing , Models, Chemical , Nanostructures/chemistry , Oxygen/chemistry , Polymers/chemistry , Polytetrafluoroethylene/chemistry , Surface Properties , Time Factors , Water/chemistry
19.
Langmuir ; 22(18): 7552-5, 2006 Aug 29.
Article in English | MEDLINE | ID: mdl-16922532

ABSTRACT

Pulsed plasma-chemical deposition of poly(4-vinylpyridine) is found to be a highly effective way of functionalizing solid surfaces with pyridine ring centers. These surfaces can be metallized via complexation to Pd2+ ions from solution, followed by autocatalytic electroless deposition of either copper or nickel films.

20.
J Phys Chem B ; 110(34): 17161-6, 2006 Aug 31.
Article in English | MEDLINE | ID: mdl-16928012

ABSTRACT

6-Amino-6-deoxy-beta-cyclodextrin can be immobilized onto a range of solid surfaces via reaction with a predeposited pulsed plasma poly(glycidyl methacrylate) layer. X-ray photoelectron spectroscopy, infrared spectroscopy, and quartz crystal microbalance measurements have been employed to monitor guest-host interactions between N,N-dimethylformamide or cholic acid and surface-tethered 6-amino-6-deoxy-beta-cyclodextrin barrels.


Subject(s)
Polymethacrylic Acids/chemistry , beta-Cyclodextrins/chemistry , Biosensing Techniques , Cholic Acid/chemistry , Dimethylformamide , Formamides/chemistry , Hydrophobic and Hydrophilic Interactions , Spectrophotometry, Infrared , Surface Properties
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