Precise Definition of a "Monolayer Point" in Polymer Brush Films for Fabricating Highly Coherent TiO2 Thin Films by Vapor-Phase Infiltration.

In this work, we show that in order to fabricate coherent titania (TiO2) films with precise thickness control, it is critical to generate a complete polymer brush monolayer. To date, demonstrations of such dense polymer monolayer formation that can be utilized for inorganic infiltration have been elusive. We describe a versatile bottom-up approach to covalently and rapidly (60 s processing) graft hydroxyl-terminated poly(2-vinyl pyridine) (P2VP-OH) polymers on silicon substrates. P2VP-OH monolayer films of varying thicknesses can subsequently be used to fabricate high-quality TiO2 films. Our innovative strategy is based upon room-temperature titanium vapor-phase infiltration of the grafted P2VP-OH polymer brushes that can produce TiO2 nanofilms of 2-4 nm thicknesses. Crucial parameters are explored, including molecular weight and solution concentration for grafting dense P2VP-OH monolayers from the liquid phase with high coverage and uniformity across wafer-scale areas (>2 cm2). Additionally, we compare the P2VP-OH polymer systems with another reactive polymer, poly(methyl methacrylate)-OH, and a relatively nonreactive polymer, poly(styrene)-OH. Furthermore, we prove the latter to be effective for surface blocking and deactivation. We show a simple process to graft monolayers for polymers that are weakly interacting with one another but more challenging for reactive systems. Our methodology provides new insight into the rapid grafting of polymer brushes and their ability to form TiO2 films. We believe that the results described herein are important for further expanding the use of reactive and unreactive polymers for fields including area-selective deposition, solar cell absorber layers, and antimicrobial surface coatings.

Assertive community treatment of the mentally ill: service model and effectiveness.

OBJECTIVE: To provide a description of the service delivery model of an assertive community treatment (ACT) team in the management of a group of severely mentally ill patients and examine the effectiveness of this team in reducing readmissions to a psychiatric inpatient service. METHOD: A clinical case audit was performed on a single day in September 2001. Admission episodes and duration were collected for patients registered with the team in the 12 month period prior to ACT and for a period of 12 months ending on the day of the audit. Forty-three patients were registered with the team at the time of data collection. The majority (79%) were diagnosed with schizophrenia and there were high rates of comorbidity (76%) and disability (mean Global Assessment of Functioning score 45.9). The main outcome measures were the number of readmissions and readmission days before and after the institution of ACT. RESULTS: The mean number of readmission days reduced from 70.9 to 10.2 (p<0.05) following the institution of ACT. CONCLUSION: Assertive community treatment conducted in a naturalistic clinical environment is effective in significantly reducing the number of readmission days in a group of patients suffering from long-term and persistent severe mental illness.