Coalescence of bubbles covered by particles

The interaction between two bubbles coated with glass particles in the presence of a cationic surfactant (cetyltrimethylammonium bromide, CTAB) was studied experimentally. The time taken for two bubbles to coalesce was determined as a function of the fractional coverage of the surface by particles. The results suggested that the coalescence time increases with the bubble surface coverage. Interestingly, it was found that although the particles did not have any physical role in film rupture at low surface coverage, they still added resistance to film drainage. For particle-loaded bubbles, the initial resistance was due to the lateral capillary interactions between particles on the interface, which hold the particles firmly together. The coalescence dynamics of bubbles was also observed to be affected by the presence of attached particles.     

Synthesis and antimicrobial activities of some sulphur containing chromene derivatives

A series of 3,3-dimethyl-3Hbenzothieno[3,2-f][1]-benzopyran analogues modified at the pyran 1,2-double bond were synthesized. The corresponding dihydro and (+/-)-cis-diol derivatives were converted into diacetate and cyclic carbonate upon acylation. The title compounds were characterized by spectroscopic analysis and screened for their antimicrobial activity in vitro.     

Spectral Characterization and Antimicrobial Activity of Some Schiff Bases Derived from 4‐Methyl‐2‐aminophenol

A series of N‐(5‐methyl‐2‐hydroxyphenyl)‐(2/3/4/5‐substituted)‐benzaldimines ( I – XIII ) were synthesized using appropriate synthetic route. Their structures were characterized by FT‐IR, UV‐Visible, ESI‐MS, ¹H‐ and ¹³C‐NMR spectroscopic techniques and analytical methods. The crystal structure of N‐(5‐methyl‐2‐hydroxyphenyl)‐3,4‐dimethoxybenzaldimine ( XIII ) was determined by X‐ray diffraction at room temperature. Relationship between the melting points and the structures of the compounds were examined. Antibacterial activities of the compounds were evaluated against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa and Proteus mirabilis. Antifungal activities were reported for Candida albicans. Some of the Schiff bases showed considerable antimicrobial activity against S. aureus and C. albicans.     

Spectral and Luminescent Properties and Electroluminescence of Polyvinylcarbazole with 1,8-Naphthalimide in the Side Chain

A novel copolymer with moieties capable of charge transport and light emission on the basis of polyvinylcarbazole and 1,8-naphthalimide is synthesized. A bright and stable electroluminescence from single layered structure is observed. White light emission can be easily realized by tuning the content of naphthalimide moieties or a number of naphthalimide derivatives. Such approach can be considered as a common way to create single layered light-emitting devices with a stable white emission.